Edible Flowers Project, Parts 1-9

Note: This is my thesis from 2013 on edible flowers. It covers the history and use of edible flowers, and then goes into detail on five flowers I selected. The artwork for this project is visible under the Botanical Illustrations and Diagrams sections of my portfolio. This post includes all parts of my thesis paper. Numbers refer to references at the bottom of the post.


Edible Flowers

Edible Flowers in History

There are many stories that could be told about how edible flowers got to where they are today. Edible flowers have been involved with cultural symbolism, with medicine, botany, horticulture, and money. Plants have been essential to people since before there were people. Besides the obvious use of food, plants yield medicine, dyes, fiber and other assorted substances as well as visual and ecological benefits. Not all plants are useful; they can be poisonous, invasive, ugly, or prickly, so people have always made note of what plants were good and what they were good for. (27) Flowers have been used in cooking for a very long time all over the world. In 16th and 17th century Europe, flowers were very common in cooking. (3)

Because plants are so useful, the study of plants in of themselves, i.e., botany, was not considered separate from the study of their practical uses until relatively late in human history—roughly around the 1500s. While “herbals,” books about plants, have been around since the ancient Greeks and Romans (and before that in China, India, and other centers of civilization), they were medical books, and the plants in them were grouped by use or whatever system the author felt like. These books tended to be illustrated sparingly and with little effective detail; images were often crudely copied, reused for different plants, small, inaccurate, and basically useless. At the time, it was considered that the text was the authoritative guide to plants, and the images were nothing more than decoration for the page. (27)

Considering that “modern medicine” was only developed in Europe in the 1700’s (and has only resembled the medicine of today for a century or so), it should not be surprising that medicine for much of human history was plants (and assorted religious ritual). (4) It is reasonable to suppose that there was no point in writing down how to grow wheat when it was commonly known, but how to cure a fever would be a rarer skill and more important. Therefore, herbals were the dominant form of discourse about the uses and identification of plants. (27)

In Europe, herbalism was basically conservative; old herbals (written by Greeks or Romans) were considered authoritative and much effort went into trying to fit the plants of northern Europe into the descriptions written down thousands of years ago. This resulted, predictably, in a degree of mismatch between the herbals and the plants used in many parts of Europe, though many Mediterranean plants adapted somewhat to northern climates. Old woodcut images were considered best to use. There were occasional new images commissioned, which varied in their accuracy and whimsy, since many artists would heavily stylize or edit a plant to match ideals of symmetry and composition. (27) Marco Polo’s voyage to China reopened trade of herbs between Europe and China, and this trade resulted in an influx of new herbs. (4)

Herbals continued to be made and copied in Europe and other countries through the 1700s, incorporating new plants from the increase in trade to India, China, Africa, and the Americas. As more and more new plants were discovered, the old herbals were no longer adequate to cover the profusion of new plants, and European herbalism scrambled to incorporate new medicines while European scientists scrambled to decide just how all these plants were related. (4,27) Botanists began devising classification systems, and botanical illustration changed from decorative to essential, since many foreign plants could not be transported alive. Botanical illustrators would work from dried specimens, sketches, and images produced by native artists. So many new plants were brought to Europe that botanists became obsessed with classification, and for the first time turned their attention on plants that were not explicitly medicinal. This attention began the split between the study of plants and the study of medicine and was the beginning of botany as a discipline important in its own right. (27) The plant trade and shift in illustration brought horticulture to the fore, and a subset of botanical illustration devoted itself to producing images of garden flowers for sale and the idealized flowers florists (breeders) grew for shows. (27)

As plants split from medicine, medicine split from plants; though herbalism was a time-honored tradition, by the late 1700s doctors in the trade which would evolve into modern conventional medicine developed the idea that healing could come from minerals, and that healing from mineral concoctions like calomel was the superior and correct method of healing. “Mineral cures” including mercury and arsenic, along with bloodletting, became so popular and monolithic that other types of healing, including herbalism and a variety of other methods were practically crushed out of existence in Europe and North America. (4) The debate over what kind of healing was best was a vicious and bitter fight, where political maneuvering, slander, and all sorts of nasty goings-on sullied the reputation of all non-conventional medicines. Anything besides the mineral cure was considered “ignorant superstition” and was stamped out deliberately. (34) Herbalism and other medicines survived in rural areas and other countries, where the traditions were too embedded in the culture, or mineral cures too expensive. (4)

Around the same time, the industrial revolution brought canning and preprocessed mass-produced food into existence. The rise in popularity of preprocessed food resulted in a drop in the consumption of spices and herbs in cooking. (30) It seems reasonable that delicate flowers, that can be bruised so easily and whose flavors degenerate quickly (and are quite heat-sensitive), (21) would have been very unsuitable for canning and therefore were not made or promoted among the new foodstuffs. These four trends—the transformation of botany into a separate and scientific discipline, of flowers from food into expensive visual displays, of medicine into a plant-free (and plant rejecting) trade, and the change from home processed to factory processed food—all came together in roughly the same period of history, the 18th and 19th centuries, to destroy, sometimes actively, the knowledge of what flowers were good to eat and the practice of eating them.

While the cultural trends resulted in a great loss of knowledge in America and Europe, not all of it is gone. There were many avenues through which the use of flowers survived. Flowers grown for other uses like flavoring teas or drinks or in toiletries, perfumes, and so on were still grown despite not being eaten directly. Broccoli and artichokes probably survived because they are not grown for visual appeal and stand up fairly well to cooking. Hops survived for its use in beer, and many other flowers survived in similar ways. Flowers survived as well for social, economic, and cultural reasons. Most of the trends described were greatly lessened outside of North America and parts of Europe, so cultures that used edible flowers never underwent the process that scrubbed eating flowers from consciousness. Even in Europe, flowers were preserved in rural areas where they grew freely and other foods were too expensive, and by the wealthy, who could afford to have delicate blossoms on their food. Some old cookbooks survived, from which we can see the old recipes.

The drastic loss of flower knowledge over the previous centuries prompted Eleanour Sinclair Rohde to write, in 1920, a compendium of spices and edible flowers and their uses and recipes, compiled from old cookbooks. (3) This compendium was the first of the books devoted directly to edible flowers and has been succeeded by more recent books.


Edible Flowers in Food

Since the European tradition of edible flowers dates from before modern cookbooks, understanding and following a recipe can be quite difficult. Old cookbooks suffer from three main issues. First, they call for ingredients using their common names, which are very unreliable for plant identification. (6) Second, some recipes call for ingredients that are now known to be poisonous or dangerous, (6) and third, some recipes don’t work. The third reason is the easiest to explain: before Fanny Farmer’s time (the late 1800s), cookbooks rarely used measures or weights, preferring to use handfuls or other subjective measures. Old recipes are frustratingly vague to a modern reader. (35) For a modern cook, there are plenty of modern recipes that give the right proportions, but the first and second reasons are still a problem.

Why are common names so bad? To begin with, take the plant Calendula officinalis. It has the very common common name of “Marigold,” a name that was applied to many yellow flowers and today refers to not just calendula but also to plants of the genera Tagetes and Caltha, not all of which are edible or palatable. (13,28) Other common names such as “heartsease” or “lily” are very unreliable, especially since the newfound plant trade of the 1400s through 1700s resulted in many foreign plants being misidentified as local plants. (4)

This plant trade also introduced new medicinal plants, which while reputed to cure diseases were often of varying levels of toxicity, interactions, and effectiveness. Some recipes were intended to cure ills as well as taste good, and some medicinal plants like foxglove (which contain cardiac glycosides) were used in food at sub-medicinal levels. (6) Herbal medicines, like modern drugs, can be dangerous if used improperly, and some food plants have medicinal or toxic properties if eaten in sufficient quantities or may interact with drugs.1

For both of these reasons, a modern eater must be careful about what flowers he eats, as well as how they are grown, prepared, and cooked. Most books recommend growing flowers organically, along with never eating flowers from a florist or cut flowers, since chemicals used on nonfood plants may not be approved for consumption and in any case chemicals concentrate in the flowers. Of course, one must also know what plant it is they are consuming. Most books consider plant identification down to the species to be necessary, unless an entire genus is known to be edible. They warn against eating flowers used for garnish (you don’t know exactly what it is) as well as avoiding any plants that cause allergies for you. And of course, like any new food, they should be eaten in small quantities at first. (1,6,28)

Once you have decided to eat flowers and chosen a good plant, most flowers should be picked in the morning once the dew has dried, on the day they are ripest, and either used or preserved within a few hours. They can be held in a glass of water or in a sealed bag with damp paper towels, depending on the type of flower and how long they are to be held. Aside from cooking, flowers can be candied or dried to prolong their shelf life. For most flowers, only the petals are eaten, but with some the entire flower can be consumed. Once the flowers are ready to be used, the options are truly generous: flowers can be used as a garnish, in jams, butters, sauces, to flavor meat and onions, in syrup, candy, drinks, liqueur, salads, salsa, soup, muffins, stir-fry, cakes, breads, syrups, oils, vinegars, and practically any other kind of food. Flowers have flavors ranging from sweet to minty to peppery and as substitutes for expensive spices such as saffron and cloves. (1,6,28) Off the table, plants bearing edible flowers can fill other jobs. The flowers of many edible plants are edible, such as elder, apple, basil, sage, arugula, cucumber, chives, thyme, rosemary and lemon verbena. (28) Many ornamentals are edible, including roses, marigolds, calendula, daylilies, nasturtiums, mums, pansies, dandelion, hibiscus, and lilac. (1)


Process and Design

The beginning of this project lay mostly in my interest in the flowers that grow in my lawn and garden. Violets, my favorite flower, grow alongside white clover in my yard. In front of our house are beds of my father’s carefully bred daylilies. I was intrigued to learn that clover and violets are edible, and thesis came up, I eventually settled on the idea of edible flowers, because I thought the idea was unusual and interesting. I began by searching out some lists of edible flowers, from which I made a short list of my own. This was gradually whittled down into a list of five, chosen by several criteria. First, they had to have a variety of shapes, patterns, and colors, to give the art visual variety. Second, they had to be a flower I could get my hands on so that my reference images would be my own photographs. Third, they had to have some sort of significance beyond edibility, and fourth, they had to not be part of a plant we already eat. I settled on red clover, calendula, carnations, sweet violet, and daylilies for these reasons. The last three are also members of important genera, so I could research beyond a single species.

The shape of the exhibition is inspired mainly by museums and my late mentor Tom Steigerwald, whose artwork is almost exclusively large-scale botanical illustrations. I planned to have each flower in a display, composed of a large central image, several ancillary images, and a shelf of products. Each display is a little section in of itself where a visitor could learn about the aspects of the flower and also see that it is possible to find the products. This plan is essentially intact now, though what images, sizes, and compositions I use has changed as I created art, researched, and shopped.

The main image is the eye-catcher, intended to be bright, colorful, detailed, and interesting, so a visitor can see it across the room and still have something to look at up close. These images are mixed-media: watercolor, colored pencil, and acrylic paint. Below the main image are the accessory images. The anatomical drawings are in pen and ink, shaded with stippling. An old-fashioned and respected medium in scientific illustration, this is intended to call to mind old catalogs or textbooks. Horticultural flowers have digitally created palettes and images of shapes and patterns, to demonstrate the variety of appearances they have. Scientific flowers have diagrams illustrating their significance and uses, which are clean and have muted colors intended to enhance but not distract from the information in the image. To offset the abundance of digital images, there are watercolor and ink images of the food uses of the flowers. Most of the images are not of the same size, which creates a pleasant variation in each display.

In front of the art is a small shelf of products. This shelf is intended to remind the visitor that the flowers are not just academic exercises, but actually available as real products, commercial or handmade. Like in a museum display, having actual items rather than just images makes the information more real by attaching it to actual things the visitor can see. The products are carefully sealed in their containers or in glass to prevent odors or allergens from leaking and are situated behind a barrier so that visitors are not tempted to sample the products. The items were accumulated from a variety of sources, which ranged from stores in Manhattan and Berkeley, to the Reading Terminal Market, and online at Etsy and other online marketplaces. Some were very easy to find and others required much effort, representing the varying level of awareness of these plants in our society.

Since the displays are intended to be educational, they are arranged in a line so that each display can be gotten close to. Visitors should be able to lean in and read the text and study the diagrams, which are aimed at high school students and up.

This project came with some difficulties, mostly in procuring the plants. During the course of the project, none of the flowers were in season. I already had my own daylily photographs. I dissected and photographed cut carnations and potted pinks. I got photographs of calendula by growing them in a pot and scouring the Philadelphia flower show. I found several specimens of red clover growing in a parking lot in Bryn Mawr and brought them home to dissect and photograph. As for violets, I own pansies and have many images of blue violets in my yard, but none of the right species. I bought specimens to photograph, from which I got pictures of foliage, but the plants succumbed to pests before producing any flowers. Therefore I have used blue violet as my main reference point, with minor variations to account for the differences between species.

The following sections deal with the science of each flower and the research behind my images. Their histories, ethical, cultural, ecological, and other significances are dealt with therein.


Red Clover

Trifolium pratense

The red clover, Trifolium pratense, is closely related to white clover, commonly seen in lawns. It is a small plant that can grow up to two feet tall, (19) and can be distinguished from its relatives by its very hairy stems and foliage. It has a white crescent on its leaflets. (4) Red clover is commonly grown as a self-seeding biennial or annual1 but is technically considered a short-lived perennial. (19) It is found as “a familiar weed throughout North America” and grows in lawns, fields, meadows, and disturbed areas. (1) Originally native to Europe and temperate parts of Asia, (14) it was brought to and naturalized in North America (1) and Australia (4) because of its value as a forage crop for grazing animals. Red clover is used as a hay crop and an important food source for honeybees and bumblebees. (19) The species was seen by Bartram in North America before the American Revolution. (14)

Red clover, like many members of the pea family, contains isoflavones and is used for tea, food, and medicines. (9) It is used as an expectorant for coughs, (4) particularly persistent and violent coughs, for healing ulcers and burns, for the appetite, and as a folk cancer remedy. (9) While it is considered a useful plant because of phytoestrogen content, red clover must be used carefully. (9) It can cause a skin rash in some people,1 and can interact badly with blood thinners. (9)

Besides medicine, red clover, like other clovers, has been used for food. Both red and white clovers are edible. (1) The entire head is eaten, (1) and is usually ground and cooked, since it is difficult to digest when raw. (1) The flowers are said to taste sweet. Clovers were traditionally eaten by the Native Americans of California and Arizona, and also in Ireland during famine. (14) Flowers were cooked between hot rocks, (14) eaten like salad, (19) or boiled in soup. (14) The flowers can be dried and made into tea (1) or ground into flour and baked. (1) Clover is most commonly eaten today as honey, which has a light floral taste. (2) Clover cordial was a popular drink in the early years of San Francisco. (1)

Red clover’s ecological significance comes from two sources: its affinity for nitrogen-fixing bacteria and its use as bee fodder. Like most legumes, red clover supports symbiotic bacteria that live in root nodules. (25) These bacteria transform plant-inaccessible atmospheric nitrogen into accessible ammonium ions. Plants, like animals, require nutrients to survive, and nitrogen is an essential nutrient, used in amino acids, nucleotides, chlorophyll, and coenzymes. A deficiency in nitrogen causes widespread chlorosis, with leaves eventually turning entirely yellow and falling off. Botanists consider the process of fixing atmospheric nitrogen into organic molecules a process almost as essential to life on earth as photosynthesis and cell respiration. (25)

Nitrogen is plentiful—our atmosphere is 78% nitrogen gas (N2), but for most life forms, atmospheric nitrogen is inaccessible and useless. The plant accessible form, nitrate (NO3-), is an anion and therefore quickly leached from the soil by water. Accessible nitrogen can be lost when plants are harvested, removed, or burned, or by the action of denitrifying bacteria that in the presence of an energy source convert NO3- into N2 and N2O. Nitrogen’s inaccessibility and easy loss makes the natural processes that replenish nitrogen essential to the health of the ecosystem. Nitrogen is often a limiting factor in plant growth. (25)

Nitrogen is replenished in the soil from two chief sources: the recycling of decaying organic material and bacteria that convert nitrogen gas into ammonium ions. Decaying organic material is consumed by tiny organisms in the soil, including bacteria and fungi, which emit ammonium ions (NH4+) as a by-product of metabolism. Some plants have mycorrhizae, or symbiotic fungi that surround their roots. These mycorrhizae greatly expand the effective surface area of the roots and can process decaying matter directly into amino acids, which the fungi pass to the roots of the plant. This adaptation shows up most often in poor soils with low nitrogen content. Some plants bypass poor soils by being carnivorous; they consume animal protein as a nitrogen source. The Venus Flytrap is a well-known example. (25)

Most soil nitrogen is replenished by various strains of nitrogen fixing bacteria. Some grow directly in the soil, but by far the most nitrogen-fixing activity happens in the root nodules of legumes and a few other plants. These plants are closely adapted to particular strains of bacteria. The bacteria, upon encountering compatible root hairs, burrow inside the root via “infection threads.” These threads grow and split, inducing the root to develop membrane envelopes. The bacteria colonize these envelopes and enlarge into bacteroids. The root swells, creating a tumor-like blob, called the nodule. The nodule has a thin cortex with vascular bundles and an interior filled with bacteroids. Both the plant and the bacteria interact closely to regulate the environment inside the nodule, including the critical level of oxygen, which is necessary for respiration but inhibits the enzyme that fixes nitrogen. Inside the nodule, the bacteria convert N2 into ammonium ions and release it into the vascular bundles. Ammonium in the soil is converted by free-living bacteria into nitrite and then into nitrate, which is the most plant-accessible form of nitrogen. Crops like red clover and other legumes add ammonium to the soil while they live, and can be harvested for hay (leaving the nitrogen-rich roots) or simply plowed under. (25)

Clover is well known as beneficial to soil because of nitrogen, and consequently is grown in crop rotation or as a companion. (25) Red clover is grown as a ground cover underneath fruit trees, nut trees, and grapes, sometimes combined with mustard. (26) It fares badly when planted near buttercups or henbane, which release chemicals that harm the nitrogen-fixing bacteria. (26) In particular, red clover is good as a ground cover in poorly aerated or acidic soils, which other legumes do not tolerate. Red clover’s ideal pH is about 6.3. (26) Most plants have a very narrow range of tolerable pH, which is critical because pH changes the solubility and accessibility of essential plant nutrients. (25)

Red clover’s other significance is its ability to supply honey. Most of the honey produced in the world today is some variety of clover honey, because it has a light color and mild, indistinct flavor. Clover honey is considered “standard.” (8) Clovers make excellent bee food and are grown in large fields. (32) Commercial honey is largely made by bees of the species Apis mellifera, out of the estimated 16,000 species of bees. Other bee species produce honey, but A. mellifera is what we commonly think of as a honeybee. Bees begin their lives as small fast-growing larvae in special cells in the hive, called brood cells. They live on a diet of pollen supplied by worker bees and rapidly grow, changing into pupae and then morphing into adult bees. Young adult bees are called “house bees” because they live entirely inside the hive and perform maintenance tasks such as helping the queen, tending to the larvae, making wax, and evaporating nectar into honey. Adult bees of about three weeks of age begin to leave the hive and gather honey and pollen, (2) which they will travel up to five miles away from the hive to get. (8) Bees die at about six weeks of age from exhaustion and wing damage from flight, and will fly away from home to die so as not to litter the hive. Queen bees live several years, constantly laying eggs after their mating flight. One hive can produce 150 pounds of honey a year, from which they need around 50 to eat during a typical cold winter. (2)

Bees present the primary ethical relevance of red clover. Bee larvae grow rapidly, almost explosively, and take only five and a half days to go from egg to pupa. (8) This growth is fueled by large amounts of pollen, which worker bees supply by heading out to flowers. Worker bees will only visit one species of flower per trip, which maximizes their pollination potential. Red clover, like many plants, is self sterile and requires bees to reproduce. (32) Considering that red clover is a forage plant for grazing animals such as cows that supply meat and milk, a lack of bees would impact not just the fruit and vegetable supply but animal products as well. It is estimated that bee pollination, by wild or commercial bees, directly or indirectly accounts for a third of the food in the world. (2)

The larval diet of pure pollen presents two problems for bees. First, people enjoy eating honey made from only one flower species, or want the bees to pay attention to only one crop. The nutritional needs of bee larvae may not be suited to only one species of pollen; they may not be as vigorous with only one source. (8) Second, beehives are vulnerable to pesticides, herbicides, and chemicals. Aside from chemicals in honey, chemicals on pollen are fed directly to larvae, impacting the health of the hive. Since bees are often “farmed out” to pollinate crops, chemicals sprayed on crops invariably make their way into hives. Red clover, like other bee-popular plants, is grown in large fields and sometimes monoculture. This allows a great deal of nectar to be harvested by bees, but tends to restrict the diet. Monoculture-induced poor nutrition, combined with a plethora of pesticides, may have combined with natural bee diseases and parasites to contribute to colony collapse disorder, which is threatening commercial beehives across the world. (2)



Calendula officinalis

Calendula is famous for its medicinal uses, but could probably be just as well known for having the most confusing assortment of names. Commonly called “Pot Marigold,” Calendula officinalis has also gone by the names Mary’s gold, golds, sunnes bride, poet’s marigold, husbandman’s dyall, and just “marigold,” a name it shares with unrelated flowers of the genera Caltha and Tagetes. (29) Calendula officinalis has been used in medicine and cooking for thousands of years. (17) It was used by early Indian and Arabic cultures as a medicine (17) and was first mentioned in Europe in the 1200s. (30) In such an old and well-known flower, name confusion is hardly unexpected; calendula earned the name “Mary’s gold” (like many other yellow flowers) for its association with the Virgin Mary, which turned to “marigold” (30) and then “pot marigold” for its extensive uses “in the pot,” i.e., for cooking. (20) Romans called it Kalandae because they believed it would flower on the first of every month. (17) Though it has a variety of names, “marigold” is its most common and most confusing name. Calendula officinalis is edible and tasty, but not all members of Tagetes and Caltha are, and inattention to names can result in inedible or simply disgusting dishes. (28)

In modern times, calendula is still “widely cultivated for medicinal, culinary, and ornamental purposes.” (17) A hardy, pest resistant annual plant, calendula can be grown easily from seed (4) and is commonly planted as a border flower. (13) It prefers full sun in cool, moist, well drained, neutral and somewhat rich soil and may die from frost or extreme heat. (13) The pretty, daisy-like flowers are orange, yellow, or apricot colored1 and can flower almost year-round in the right habitat. (22) Calendula is also planted as a companion plant; it is said to repel the Mexican Bean Beetle, help tomatoes and apple trees, and suppress nematodes that attack strawberries and roses. (26)

Historically, many cultures believed calendula to have medicinal properties, an idea somewhat supported by more recent scientific studies and analysis of its chemical constituents. (13) Its powers ranged from general warding off of evil, believed to come from its association with the virgin Mary, (30) to helping in court, protecting against evil influences and disease, and “[giving] one prophetic dreams and [making] dreams come true.” (13) In the 1500s, “those who drank a potion made from marigolds were reputed to be able to see fairies.” (22) As with many flowers, it has some myth and meaning associated to it. Calendula’s associations include jealousy, (30) grief, sadness and distress, (15) the sun, the masculine gender and the element fire. (13)

Beside somewhat magical-sounding effects, calendula has an extensive and long-lived history as an essential medicinal plant, believed to have wide-ranging beneficial effects, (13) being both a strong and effective remedy, yet gentle enough to use on both infants and the elderly. (13) Calendula was “described in nearly all of the early herbals” (14) and “in the Middle Ages, [calendula] was used to treat a range of ailments, including intestinal problems, smallpox, and measles. Externally, the plant was applied in the treatment of conjunctivitis, burns, and eczema.” (17) Ancient Romans “used [it] to treat headaches, toothaches, and even tuberculosis” while in the “American civil war [they] found it helped stop wounds from bleeding.” (22) Calendula was once used to lend a yellow color to pale cream, which is probably why butter was once listed as a burn remedy. Butters no longer use calendula for coloring. (13)

While calendula was a respectable staple in medicine, it was a cooking plant as well. It was used as a substitute for saffron in Roman times1 and to thicken and color soups (29) among other uses. Only the petals are used in cooking, either dried or fresh. It is said to have a tangy, peppery, or bitter taste, (6,28) though modern Calendula officinalis has been bred such that while the flowers have gained in size, they have lost in flavor. (7) Calendula is used as a coloring or for flavor in soup, muffins, salad, soufflé, rice, biscuits, omelets, vinegars, butters and cheese or as a garnish. (6) The yellow color comes out best in foods with at least a little oil and when the petals have been bruised or minced. (1,6)

Calendula “has had both culinary and medicinal applications for centuries,” (22) being used in foods, cosmetics, (17) bathing products, and herbal medicines. Calendula’s “most outstanding distinction” is its use against all types of skin problems. Books that claim calendula as a medicine often have long lists of its purported uses; Green writes that it is an analgesic, anthemintic, antispasmodic, astringent, alterative, anti-inflammatory, aperient, bactericide, carminative, cholagogue, depurative, diaphoretic, diuretic, emmenagogue, febrifuge, stimulant, stomachic, styptic, tonic, and vulnerary, collectively meaning it does good things either directly or indirectly for most parts of the body. (13) Mainly, calendula is said to reduce pain and inflammation, be particularly good for skin problems like insect bites, rashes, and eczema, and detoxify the digestive system. Its only contraindications are that it should not be used internally during pregnancy or at all if you are allergic to it or similar plants. (13)

Since calendula has been used for so long, it makes a perfect example of the ethical considerations of medicine, a complicated and multifaceted debate. Calendula, when consumed in the small quantities usually recommended for cooking, has no medicinal properties. (31) It is used as a medicine and cosmetic aid and has been for millennia, but while it carries an impressive list of fancy medicinal words, scientific studies that support its properties are not as profuse as one might like. While its chemical constituents have been analyzed, and some of them are known to be bioactive, (23) not all of calendula’s properties have been scientifically tested. Studies have shown, however, that extracts of calendula have anti-inflammatory, antiviral, and immunostimulant properties, (9) may act against abdominal cancer, (23) and may have uses against HIV. (13)

Much of the ethical issues around calendula are simply the ethical issues of alternative medicine. Historically, alternative medicines have been maligned. The rivalry between conventional medicine and alternative medicines (and among the various kinds of alternative medicines) has existed since long before any medicinal practice contained science, with conventional doctors calling practitioners of alternative medicine quacks and alternative doctors claiming that conventional medicine exists just to sell drugs. It has been extremely vicious, with deep-set prejudices on all sides and doctors losing credibility with their fellows should they even hint that another practice might have some merit. (34) Therefore, it is dangerous to assume that calendula, like other herbs, either does or does not have medicinal properties, simply because one prefers herbal medicine or conventional drugs. Chevallier writes “one reason why the medical profession has generally preferred conventional medicines to herbal ones is the difficulty of guaranteeing quality in herbal remedies,” and like other drugs, herbal medicines may produce side effects. (4) “Like all medicines, herbal remedies must be treated with respect.”(4) There is some perception, which has existed for hundreds of years and recently tied to the environmental movement, that if a remedy is “natural” that is must be good and harmless, but there are many known harmful natural chemicals, with effects ranging from rashes to allergies to cancer. (3)

Still, in the absence of (sufficient) scientific evidence, is it reasonable to trust herbal medicines to behave as they are supposed to? Many plants famous for healing properties (like chamomile for the stomach) have been shown to contain active chemicals responsible for their effects. (4) In some cases, plants may be more effective than drugs prescribed for the same symptoms. As a result of these trials, modern herbalism can be much more precise about dosages and effects of herbs. Conventional research is now turning to stores of native medicinal plants in hopes of testing their efficacy and possibly isolating new drugs. Still, “it is easy when concentrating on the scientific aspect of herbal medicine to forget that much, in some cases all, that we currently know about a particular plant results from its traditional use.” (4) In the end, it may be problematic to judge a practice as a whole, rather than individual techniques and medicines.


Sweet Violet

Viola odorata and viola spp.

The sweet violet, Viola odorata, is well known as a flower of delightful scent. (5) It is a small plant with basal, almost circular dark green leaves, and small purple or white flowers that taste and smell “strong, sweet, very floral,” (6) and perfumed. The leaves are “a delicious salad accompaniment” with a “slightly tart” taste. (1) The sweet violet is just one among many; practically every plant of the genus Viola is edible with a pleasant (if occasionally bland) flavor. (10) While sweet violet is known for its aroma, its cousins the viola and the pansy are known for their flowers in the garden.

The sweet violet is native to North Africa, Europe, and Asia, but is naturalized in North America. (1) It reproduces by stolons and is often considered an invasive lawn weed. Sweet violets are hardy perennials (10) and are one of the few plants that tolerate dry, shady conditions well. (5) Violets have no particular preference for sandy or clay soils, (10) but pansies and violas prefer a rich, slightly clayey soil, preferably dug deep and fertilized with buried manure. (5) Pansies and violets, if planted close together, will merge into one even field of flowers. (10) Since pansies and violas have blossoms of all colors except green, the effect of a field of pansies can be quite beautiful. (5)

All of the flowers of the genus Viola have a similar flower structure, each part varying only in size, shape, and color. There are five petals: the bottom petal, two side petals, and two top petals, and five small greenish sepals behind. A spur with a nectary lies below and behind the stigma and stamens. (10) The entire violet flower is edible, both petals and sepals, and while it should be washed, does not need anything removed. (1) Consequently, the petals or entire flower are perfect for candying. The variety of recipes reflects this: it is used candied or plain as a garnish, in salads, to make sugars, syrup, and vinegars, frozen in ice cubes or floating free in drinks, in tea sandwiches and custard, in jams, jelly, tea, and violet water.6,30 The sweet violet was particularly esteemed by Egyptians as a flavoring for sorbet and has been mentioned or drawn in many European herbals. (14,27) The leaves of sweet violet contain vitamins A and C and iron. (1,30) Pansies and Johnny-jump-ups have bland, somewhat vegetal-tasting petals, but their sepals taste of wintergreen. (1)

Historically, the sweet violet has appeared in many herbals and studies (27) and has gone by many names, some shared with its relatives. It is called variously heartsease, sweet viola, English violet, sweet-scented violet, and blue violet. (1,17,22,28) It was believed to be a symbol of modesty and humility, because of the way the flowers grow low to the ground and face downwards.(5) Consequently, sweet violets occur in poetry, myth, and Victorian flower language.(5,15) One myth has it that Ia, a pretty woman, was turned into a violet “to hide her from Apollo’s lusty intent.” (15) Another claims that cupid shot an arrow through a violet, “and thus endowed the ubiquitous miniature pansy with aphrodisiacal properties.” (22) Others associate the flower with Aphrodite, or Orpheus. (17,20,30) Still another claims that violets sprang from the nymph Io’s tears, after an adulterous Zeus turned her into a cow to hide her from Hera. (30) It was associated with the Virgin Mary by Christians, (20) with the graves of virgin women, (20) and Isis’ tears. (22) More recently, the sweet violet has been associated with Napoleon,(30) and Freud thought a dream of violets meant rape.(20)

Symbolically, the violet has meant courtship, (15) “modesty, innocence, and love”, “mourning, suffering, and death,” (20) was used in love potions, and to cure hangovers. (17) Pansies represented “the virtues of tender attachment, concern, and compassion—the natural qualities of a woman’s heart” (15) or more specifically, “think of me” when used in a bouquet. (15) Violet is the flower of March (20) and of Valentines Day (not the rose). (15)

Aside from their mythical importance, sweet violets were also used medicinally. Greeks and Romans considered it a cure for insomnia, gout, headaches, and anger. (1) Violet syrup or tea, made from flowers or leaves, is considered a mild expectorant and used for sore throats, cough, and congestion. (17) The root of the sweet violet is a much stronger expectorant and an emetic if enough is eaten. Other members of the genus have been used as diuretics, for eczema, and as antiseptics. (4)

Pansies are closely related to violets and are of the same genus, Viola. Unlike violets, however, pansies have been bred for shows and horticulture since the early 1800s. Their history is one of horticulture, rather than much cultural or culinary significance. (10) Their flavor, like other members of Viola, is said to be a mild sort of vegetable flavor, but the sepals are minty. (1) Out of an entire book devoted to the pansy and their growth, botany, and history, there was precisely one sentence devoted to their use in food: “in the belief that the pansy and viola are totally non-toxic, there is no end to the uses to which they might perhaps be put by those who wish to experiment with them in a culinary capacity.” (10) The ancestry of modern pansies and violas is under debate. The contributing species have been variously named as V. cornuta, V. tricolor, V. altaica, V.lutea, and V. grandiflora, but since members of Viola hybridize easily, it’s possible that the first pansies arose naturally when differing species were planted together in a garden. (5)

Violas, violettas, and pansies have been considered horticultural plants since the early 1800s, and around 1840 the “ideal” pansy was quantified. Florists began to breed pansies specifically for shows instead of just for gardens. A show pansy’s ideal was to have a bloom as circular as possible, with the lower three petals matching in color. Other attributes, such as particular colors, blotches, and different color edges, were variously considered as attractive. In particular, petals were meant to be flat and velvety. Violets, on the other hand, were left essentially wild and though they crossbreed fairly freely, were not considered show material. By 1850, most florists demanded more variety in the ideal pansy, and so the “fancy pansy” was bred. This is the kind of pansy we are most familiar with today. (10)

Violets are a familiar smell in perfume. Violet flowers have a very delicate scent and are very expensive to extract. The smell is characteristic, flowery, sweet, and somewhat woody, and produced primarily by alpha and beta ionone, among other chemicals. Alpha ionone is now synthesized in the lab, so violet scent is now a cheap and plentiful smell. Violet leaves are expensive, but not so much, and their smell is more “green,” meaning like grass or cucumber. The extract is expensive and rarely used. The abundance of artificial violet flower fragrance has rendered it a “cheap” smell and therefore it is not used much anymore because of that association. (33)

Chemicals in perfumery and other fragrance work can be extracted from natural sources or synthesized in the lab. Perfumes generally mix natural and synthetic fragrances, depending on the cost and desired effect. (33) There are several ways of extracting chemicals, the most used of which is distillation. About 80% of natural fragrance oils are distilled. Most fragrance chemicals are sensitive to heat and boil at a very high temperature. Even boiling water is too hot. Luckily, Dalton’s Law of Partial Pressure states that two immiscible fluids boiled together boil at a lower temperature than either alone, so the combination of plant material and water boils cool enough for most plants. The most volatile components in the boiling evaporate soonest. The hot steam condenses and drips into a collecting tube, allowing a technician to separate out the essential oil. For more delicate chemicals, the air pressure in the still can be lowered, therefore lowering the boiling point. Some chemicals are too volatile or delicate even for vacuum distillation, and there are two other methods to extract these oils. In solvent extraction, plant matter is soaked in solvent, which is then allowed to evaporate off under vacuum. Enfleurage is a method in which the fragrant plants are put between glass plates coated with purified animal fat, which absorbs the smells. The fat is then treated as in solvent extraction. Enfleurage is rarely done today because it is difficult and inefficient (violet flower essences must be extracted by enfleurage). Last, citrus oils are extracted by expression, which is either cutting or pressing the peels to break open the oil pockets in the skin. Citrus is uniquely suited to this method. (21)

Natural essences can be difficult and expensive to obtain, not to mention ethically dubious. Many fragrances or fixatives are animal products and hunting of the animals can drive them to extinction. (33) Luckily, the fragrance industry has found synthetic alternatives to ambergris and a way to harvest musk from musk deer without killing them. (21) Plant fragrances are no different; if the plant grows only wild and must be killed for its fragrance, then depopulation is a problem. If the plant can be farmed, then land for farming may be cut from nearby forest as in South America. (21) Aside from the problems involved in procuring them, fragrance chemicals can also cause reactions, such as skin rashes and allergic reactions. Some are carcinogenic or persist in the environment. These problems occur with both natural and synthetic chemicals, so neither lab chemistry nor a natural origin is a guarantee of safety, especially among people with flower allergies. (33)



Dianthus caryophyllus and Dianthus spp.

Carnations are the flower of culture: their significance and meanings run the gamut from presidential elections to purest love. Carnations and their close relatives, the pinks, show up in all kinds of stories, foods, medicines, and meanings since their first cultivation in the 1500s. (18) The carnation is the secret ingredient in the liqueur chartreuse, (22) “second only to the rose” in the cut flower business, (19) is the symbol of mother’s day, (20) flavors wine, (17) were strung together as garlands by Ancient Romans, and are valued for their clove-like scent and flavor. (17) Like the sweet violet, the genus of carnations, Dianthus, contains a number of closely related important plants. There is some debate about which members of the genus are edible. Many sources imply that all Dianthus are edible, but species specifically named as edible include D. caryophyllus, D. plumarius, D. deltoides, and D. gratianopolitanus (1,6,17,28). Some books list variety names from hybrids. Complicating the issue is that no one is quite sure of the ancestry of many modern pinks (save for border carnations, said to descend entirely from D. caryophyllus(18)). Modern garden pinks are mostly descended from D. plumarius, but because dianthus species interbreed easily and frequently, and scientific names have been subject to revision, it can be very difficult to know for sure what genes went into a specific plant. (18)

Carnations and pinks have been around for so long (the ancient Greeks grew them in gardens and by 1600 there were so many kinds of pinks that one writer suggested that trying to name all the varieties would be “like numbering the ocean sands”(19)) that their exact origins and some of their history is uncertain. (12) Because of their great age and history in Europe, they are featured in innumerable stories and myths, and different colors of carnation symbolize all kinds of things. Smith writes, “Few other flowers have been so representative to so many people for so many different reasons.” (30) The carnation is associated with the Virgin Mary and divine motherhood, (20) is the “flower of the dead” in Mexico, (20) was worn by French nobles on the way to the guillotine, and is worn on a hat in Austria to declare that the wearer is in love. (30) Carnations are scattered over the graves of children in some parts of Germany and were traditionally used to foretell the future in Korea. (20) The name “dianthus” means “divine flower” or “flower of the gods.” (1,19) The color pink is named after the flower, which itself was probably named after the practice of pinking, or making scalloped cuts in cloth (pink is probably a corruption of the French “pinct”). (30) The name carnation comes from “carnatio,” or flesh-colored. (30) Carnations and pinks were also called gillyflowers, which may be a corruption of the name for clove (for their scent) or of “July flower,” for when they bloom. (18)

The carnation is so symbolic that each individual color has its own host of associations. Scarlet carnations were used by McKinley’s presidential campaign, the (dyed) green carnation represents the Irish, pink is for mother’s day (30) and “I will never forget you,” and red is for “my heart breaks” or “strong love.” White carnations mean “sweet and lovely” and a gift of white carnations would be an “affectionate and tender gesture.” Yellow carnations indicate “disdain”, and a striped carnation means “I cannot be with you.” (15) Carnations could be given as bouquets to transmit a message and were popular as buttonholes. (15) Bouquets could be used as courtship, to rebuff unwanted attention, or to end an affair. Pink carnations were used in a bouquet for a young bride to hold. (15)

Perhaps because of their cultural significance, carnations have been a major horticultural plant. Ancestral carnations appeared just as ancestral pinks: small single pink flowers that bloomed in spring and summer. (19) Pinks are native to the western Mediterranean, southern Europe, and northern Africa (1,17) and prefer to grow in similar climates: hot dry summers and cold winters, with well drained sandy or rocky soil. (18) Most garden pinks are genetically quite similar to ancestral breeds, but the border carnation (the kind for cut flowers) has been bred extensively within a small gene pool. (18) Carnations and pinks have very similar anatomy, with border carnations simply being bigger, thicker, taller plants, with many petals instead of a single whorl of five. The plants are perennial with a single basal stem, opposite sword-shaped leaves, and characteristically grey-green or blue-green foliage, though some species are just green. Extensive breeding has expanded the color repertoire from pink to purple, red, white, yellow, and markings like stripes, dots, eyezones and edgings. (12) All Dianthus species are resistant to drought (12) and if they have the proper soil are quite resistant to pests as well. Still, they may succumb to ants, slugs, carnation flies, thrips, and other pests and diseases. (18)

Like with pansies, carnations have been bred for show. Show standards developed gradually and became increasingly rigid in their requirements and categories. By the 19th century the standards for show blooms were so exacting that people were employed and paid highly to use tweezers to arrange the petals of a carnation and remove any blemishes to optimally prepare each flower to be judged. (18)

Medicinally, carnations and pinks are prescribed to combat fevers (20) and for “coronary and nervous disorders.” (4) The fringed pink, D. superbus, is used as a diuretic in china. (4) Their medicinal uses may be spurious, however. Carnations were originally used in North Africa to sweeten gross medicines, and the Spanish thought this meant the carnations were themselves medicinal. Eventually its use as a medicinal plant faded in favor of its beauty and fragrance. (7) Carnations are used in food as a substitute for cloves (20) and have a sweet and spicy taste (1,17) suitable for sweet dishes and baked goods. (28) The petals of Dianthus species have a bitter white stalk that must be removed before eating. (28) Carnations and pinks are used in salad, soup, jam, syrup, wine, cake, vinegar, ale, sauce, and candied or fresh as a garnish for baked goods and drinks. (6,17,30) Carnations grown in the greenhouse are said to be less flavorful than carnations grown outside, and of course, (30) one should never consume carnations sold as cut flowers, because cut flowers are often sprayed with chemicals not approved for consumption. (28)



Hemerocallis fulva and Hemerocallis spp.

The daylily has a long and illustrious history as a source of food and beauty. The Chinese have consumed the daylily since “long before the written word” (30) and the plant has been a “respected and venerable part of regional cuisine since at least 304 A.D.” (11) The daylily is still eaten today across the world; over 4,000 pounds of it was imported as food to New York in a single year. (30) Native to Asia, (22) the daylily has been used as food by the Japanese, and also for medicine by the Chinese for more than 2,500 years. (24) The flowers are called “gum-jum”, “gum-tsoy” or “golden needles” when sold dried, (30) or sometimes confusingly just “lily flower.” Daylilies are so popular as food, that on one island, the remaining plants have survived only because they grow in a minefield. (11)

Most of the daylily plant can be eaten, but identifying the species can be difficult. Like with pinks, the name “daylily” applies to the entire genus Hemerocallis. Most sources that name daylilies as edible imply that every member of Hemerocallis has an edible flower, though some are tastier than others. (3,6) H. fulva, H. flava (11), and H. minor (14) are all known to be edible. Daylily buds, flowers, young seedpods, tubers, and young shoots can all be eaten, though some recipes for daylilies come with warnings. (11) The daylily flower opens for only one day (hence the name) (11) and is picked the day it opens. (30) The pigments that cause dark colors such as red taste bitter, so lighter-colored and fragrant blossoms are the tastiest. (11) Buds are picked the day before they open. (6) The flowers and buds are dried or pickled and used in stir-fries and soups, (14) or could be used fresh in scrambled eggs or with duck, pork, or fried. (30) Creasy suggests using the flower as a cup for sorbet or cheese. (6) Dried blossoms are easily used like fresh if soaked. (30) Despite the many tasty uses, people who eat daylilies sometimes report throat irritation or an upset stomach, (11) and the plant can be laxative and diuretic if too much is consumed. (3) Young shoots of H. fulva are said to be hallucinogenic. (11,14) It is important never to eat the actual roots of daylilies, rather than the tuber-like swellings. The root contains dangerous chemicals that may cause lasting damage even in small amounts. (11)

Outside of ethnic markets, the lily is known for its beauty and horticultural significance and not at all as food. (24) When the daylily first arrived in Europe, it was ignored, and was first cultivated for horticulture in 1890 by Georde Yeld. (11) Since then, the daylily has become increasingly popular for breeding in America, and moderately popular in Europe. (24) Daylilies hybridize easily and scientists do not know precisely how many species there are, and on top of that, daylilies vary quite widely within a single species in height and other characteristics. (24) Wild-type daylilies are diploid, but since the 1950s, tetraploid daylilies (formed by treating daylilies with colchicines) have become more popular, since they offer greater breeding possibilities. (24) Wild-type daylilies have three petals, three sepals, one fused carpel, and six stamens and are either yellow or orange. (24)

Breeders have a number of aims: to achieve new colors, to create doubles, and to create a larger and more fertile gene pool of tetraploid plants. (24) Doubles are a particularly popular breeding type. There are two kinds of doubles. One, called the “peony double,” comes from causing stamens to grow petal-like wings. These modified stamens are called petaloids. The second type, the “hose-in-hose” double, is caused by an extra whorl of tepals. (24) Because a peony double has modified stamens, they can have at most six extra petaloids, while hose-in-hose doubles can have as many whorls of tepals as the breeder can manage. Polytepal daylilies are another method of gaining additional tepals. Instead of modifying stamens or adding new whorls, polytepal daylilies change the “basic number” of the daylily from three to four or even five, so that there are four sepals, four petals, eight stamens, and so on. Breeders also aim for pretty patterns such as eyes, edges, or stains, along with different shapes of daylily, like ruffles, or shark’s tooth edging, very round petals, or extremely narrow petals. Spider daylilies have long, thin tepals that look like spider legs. Daylilies are bred to have large flowers, or many small flowers, to bloom longer or at different times, for height or shortness, and other attributes. (24)

Luckily for breeders, daylilies are very hardy plants that require relatively little in the way of cultivation, attention, and protection from pests and disease. Daylilies prefer full sun, at which they will aim their opening flowers, which sometimes causes particularly dark blooms to “toast.” Daylilies prefer slightly acidic, loose, moist, and well drained soil, but are not particularly picky about where they grow. Daylilies grow from tropical to temperate regions, and some are evergreen while others go dormant in winter. Dormant daylilies tend to require cold exposure to germinate. Most horticultural daylilies are hybrids and have ancestors of both types. Daylilies when grown with other plants are rarely attacked by pests, but if grown en masse can be bothered by rusts, aphids, spider mites, slugs, snails, earwigs, and gall midge. These pests rarely cause much damage, and wild H. fulva is almost never bothered by pests and disease. (24)

Hybrid (horticultural) daylilies are rarely eaten, because they are expensive and showy, and much less vigorous than wild-type daylilies. Hybrid daylilies will not tolerate the loss of shoots or tubers, while wild-type daylilies are hard to kill. Any daylily will produce many buds, so buds can be eaten without fear from any daylily plant. (11) Wild daylilies exhibit much greater vigor than hybrid daylilies, and are difficult to eradicate fully. Pulling one plant will leave tubers in the soil that can produce new plants, and their habit of reproducing by stolons makes wild daylilies truly invasive. (24) This presents a possible ethical dilemma. Eating the flowers and plants of invasive species will somewhat curb their growth. However, growing the species just to eat may let them escape into the wild and exacerbate the problem. There is some debate as to which species are invasive; red clover and sweet violet are variously considered naturalized, weeds, or invasive in North America, depending on the person asked and the location of the plant. (1)



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