Fifty Plants & Flowers
You May Not Want to Eat

Edible flowers have entered into a new age of popularity. Pansies, daylilies and squash blossoms now appear nightly at popular restaurants around the country. Basil florets, chive blossoms and coriander umbels adorn herbal luncheon plates. Colorful assorted petals now garnish salads of trendy mixed greens. The general population is being conditioned to accept the idea that flowers are edible. In general, this trend is a healthy one for specialty producers of herbs and flowers, but this emerging awareness holds a hint of danger. While many flowers and plants are tasty, nutritious and even therapeutic, there are, among the flora of the world, plants that are not good to be eaten and others which may actually be deadly. It then becomes crucial that responsible herbalists and restauranteurs stress the importance of proper identification of edible flowers and strict avoidance of the unknown, no matter how succulent, beautiful or beguiling.

Common names can sometimes contribute to the confusion, since the same name may apply to a tasty edible and a deadly poisonous plant. Botanical nomenclature is one tool to help avoid mistakes within the industry, but many citizens in the general population are resistant, if not openly hostile, toward Latin binomials. The next best procedure is to stress the need to know exactly which plants are safe and edible and to avoid anything with unknown properties. There is both a need and a responsibility within the herb industry to provide enough education to the public so that they can recognize and bypass dangerous plants.

A second note of caution involves taking care not to eat or recommend routine consumption of commercial flowers, due to possible pesticide and fertilizer issues. Bedding plants may be routinely sprayed to keep pests at bay in the greenhouse during their production. Many are also fertilized with overhead watering that may leave fertilizer residue on the leaves, buds, and flowers. Most cut flowers today are grown in countries around the world that may be subject to less stringent pesticide regulations than the U.S., Canada, the Netherlands and other developed nations. Even locally grown flowers may have residues on them that it might be best to avoid. Using only flowers grown specifically for edible usage, by those you trust or those which have been growing under your care for an extended period is the best policy.

Following is a list of some flowering plants that should be avoided when sampling edible flowers. Some of these are well known for their dangerous nature, while others may come as comparative surprises. It is by no means a complete list, as there are thousands of plant species whose consumption may have negative consequences. Just a caution is the rule when eating wild mushrooms, remember to consume only those flowers and plant where there is a high level of certainty as to their safety. Never ever sample a small amount of a flower or plant "just to see."

Like so many other activities, eating flowers can be a wonderful experience if done intelligently and responsibly using adequate information.

1. Colchicum autumnale Autumn Crocus, Meadow Saffron (not Crocus savtivus, true Saffron)

Toxicity: The alkaloid colchicine is concentrated in the flowers and bulbs. Can cause death. A popular mystery novel poison.

2. Convallaria majalis Lily-of-the-valley

Toxicity: All parts contain cardiac glycosides covallarin,convallamarin and convallatoxin. Can cause death.

3. Gloriosa superba Glory Lily

Toxicity: All plant parts contain colchicine and superbine; flowers also contain lumicolchicine. Can cause death.

4. Ornithogalum umbellatum Star-of-Bethlehem

Toxicity: The bulbs contain convallatoxin and convalliside; whether or not the flowers are toxic is not known. Can cause gastrointestinal upset with nausea.

5. Amaryllis species Amaryllis

Toxicity: bulbs and seeds contain alkaloids such as haemanthamine, hippeastrine, lycorine, tazzetine, amaryllidine and others. May cause gastroenteritis, vomiting, diarrhea and shivering.

6. Narcissus species Jonquil, Daffodil

Toxicity: Bulbs contain alkaloids such as galanthamine, haemanthamine, lycorine and others as well as calcium oxalate crystals. Flowers - unknown content. May cause death in large quantities; petals and sap may cause contact dermatitis.

7. Humulus lupulus Hops

Toxicity: Contains variety of volatile oils such as humulene, myrcene, caryophyllene and farnesene. May cause allergic contact dermatitis with eruptions after contact with leaves, flowers or pollen.

8. Fagopyrum sagittatum Buckwheat

Toxicity: A napthrodianthrone derivative known as fagopyrin causes photosensitization in animals. May cause hay fever and skin irritation in humans.

9. Mirabilis jalapa Four O'Clock

Toxicity: roots and seeds contain unspecified toxins. May cause nausea, stomach pains, gastroenteritis, vomiting and diarrhea, especially in children; handling roots and seeds may also cause dermatitis.

10. Agrostemma githago Corn Cockle

Toxicity: seeds contain the saponin githagin and the sapogenin githagenin. May cause severe gastroenteritis, nausea, abdominal pain, dizziness, weakness, vomiting, diarrhea and slow, labored breathing.

11. Saponaria officinalis Bouncing Bet, Soapwort

Toxicity: The seeds contain githagenin; also saponins saporubin and saporubinic acid in the roots. May cause gastroenteric irritation, chiefly of the intestinal mucosa; also the destruction of red blood cells.

12. Aconitum species Wolfsbane, Monkshood

Toxicity: All plant parts contain the alkaloid aconitine. Causes a variety of severe symptoms which may culminate in respiratory paralysis, coma and death.

13. Anemone species Windflower

Toxicity: Contains innocuous glycoside ranunculin that breaks down to form the irritant aglycone protoanemonin. May cause irritation of mucous membranes, burning of the throat, vomiting, bloody diarrhea, dizziness, fainting and convulsions. Symptoms also apply to Actae, Caltha, Clematis and Ranunculus.

14. Clematis species Leather Flower, Virgin's Bower

Toxicity: Same as above for Anemone.

15. Delphinium species Larkspur, Delphinium

Toxicity: Contains alkaloids delphinine, delphinboidine, ajacine, delphisine and others. May cause burning in the mouth, tingling skin, nausea, stomach upset, abdominal upset and other symptoms which may lead to death.

16. Helleborus niger Christmas Rose

Toxicity: Roots and leaves contain the cardiac glycoside hellebrin and others. May cause slow, irregular pulse, labored breathing, convulsions, respiratory failure and sometimes death.

17. Ranunculus species Buttercup, Crowfoot

Toxicity: Same as Anemonne, also pollen may cause respiratory irritation.

18. Dicentra species Bleeding Heart, Dutchman's Breeches

Toxicity: Isoquinoline alkaloids such as protopine and others occur in all parts. May cause labored breathing, trembling, incoordination, convulsions; large amounts may be fatal.

19. Hydrangea species Hydrangea

Toxicity: Leaves, branches and buds contain hydrangin, a cyanogenic glycoside and possibly other toxins. May cause gastroenteric distress, labored breathing, coma convulsions and fibrillary twitching.

20. Laburnum anagyroides Golden Chain Tree

Toxicity: The quinolizidine alkaloid cytisine occurs in all parts, especially the seeds and bark. May cause burning of the mouth, thirst, irregular pulse, coma, circulatory collapse, respiratory failure and death.

21. Lathyrus species Sweet Pea, Chick Pea

Toxicity: The seeds, in particular, contain a water soluble aliphatic amino acid glycoside with a nitrile group and other toxins. May cause partial or total paralysis of legs and/or arms when consumed in large amounts. Additional symptoms are transitory, paralysis is permanent.

22. Lupinus species Lupine

Toxicity: Seeds contain quinolizidine alkaloids such as lupinine and anagyrine, as well as others. May cause respiratory depression and slowing of the heart.

23. Wisteria species Wisteria

Toxicity: Seeds, pods and bark contain the glycoside wisterin and a toxic resin. May cause gastroenteric irritation, chiefly of the gastric mucosa, nausea, repeated vomiting, diarrhea, dehydration. Recovery is usually within 24 hours.

24. Linum ustatissimum Flax

Toxicity: All parts of the young plant contain cyanoganic glycoside linamarin and its homolog lotaustralin. May cause difficult breathing, paralysis, convulsions and death.

25. Ruta graveolens Rue

Toxicity: All plant parts contain furocoumarins and rutin. The leaves may cause skin dermatitis, subsequent photodermatitis; internally, large amounts of rue oil cause stomach pain, vomiting, exhaustion, confusion, convulsions and death.

26. Euphorbia species Spurge

Toxicity: The irritant sap contains various principles, which irritate the eyes, mouth and gastrointestinal tract; dermatitis in sensitive individuals. E. marginata (Snow-on-the-Mountain) has caused fatality. E. pulcherrima (poinsettia) normally does nothing but cause minor skin irritation on contact. Other Euphorbias vary in severity of sap toxicity.

27. Ricinus communis Castor bean

Toxicity: All parts, particularly the seeds, contain ricin, a phytotoxin, ricinine, an alkaloid, hydrogen cyanide and other unknown toxins. Produces a variety of terrible symptoms leading to tachycardia, convulsions, liver and kidney damage and death. Volatile emanations when in bloom may cause allergic respiratory irritation, as can handling the leaves.

28. Aesculus species Buckeye, Horse Chestnut

Toxicity: Aesculin, a hydroxy derivative of coumarin, has been found in the leaves, bark, young twigs and seeds of several species. May cause mucous membrane inflammation, nausea, headache, salivation, thirst, stupor, incoordination, convulsions, circulatory and respiratory failure and death.

29. Eucalyptus species Eucalyptus

Toxicity: The leaves of all species contain oil of eucalyptus and cyanogenic glycosides that release hydrogen cyanide (HCN). May cause gastroenteritis, labored breathing, stupor, paralysis, convulsions and death.

30. Cicuta maculata Water Hemlock, Spotted Cowbane

Toxicity: The most violently toxic plant of the north temperate zone. Cicutoxin is an unsaturated alcohol that acts on the central nervous system in about 1/2 hour. Long list of symptoms from nausea and salivation to fever, delirium, convulsions, complete paralysis, respiratory and/or circulatory failure and death.

31. Conium maculatum Poison Hemlock

Toxicity: Contains piperidine alkaloids coniine and coniceine and other toxins. Causes nervousness, gastroenteric distress, confusion, pupil dilation, weak pulse, convulsions, coma, coldness of extremities, respiratory failure and death. The hemlock tree, Tsuga species, is an unrelated plant which is not poisonous at all.

32. Daucus carota Wild Carrot, Queen Anne's Lace

Toxicity: The leaves contain furocoumarins that may cause allergic contact dermatitis from the leaves, especially when wet. Later exposure to the sun may cause mild photodermatitis. Carrot seed is also an early abortifacient, historically, sometimes used as a natural "morning after" tea.

33. Pastinaca sativa Wild Parsnip

Toxicity: All parts contain furocoumarins that may cause severe photodermatitis with swelling and blisters in about 48 hours. Purple pigmentation of affected skin may persist for some time.

34. Kalmia latifolia Mountain Laurel

Toxicity: Contains andromedotoxin in all plant parts. Mouth, nose and eyes water soon after ingestion. Gastrointestinal distress, seating, low blood pressure, slow pulse, drowsiness, convulsions and increasing limb paralysis until death follow. Delaware Indians used this plant for suicide.

35. Rhododendron species Rhododendron, Azalea

Toxicity: Grayanotoxin I and III, especially in the leaves; also andromedotoxin. Symptoms very similar to Kalmia poisoning.

36. Catharanthus roseus (Vinca rosea) Madagascar Periwinkle

Toxicity: The indole alkaloids vinblastine, vincristine and others. Smoking the dried leaves may cause incoordination, prickling of the skin and hallucinations; excessive or extended use may result in kidney and nervous system problems.

37. Nerium oleander Oleander

Toxicity: All parts, especially the twigs, green or dry, leaves and flowers contain the cardiac glycosides neriin and oleandrin. After a few hours, dizziness, sleepiness, slow, irregular heartbeat, pupil dilation occur; followed by unconsciousness, convulsions, respiratory paralysis and death. Drinking water from a vase that contained the flowers has caused poisoning.

38. Asclepias species Milkweed

Toxicity: Contains several cardiac glycosides, which may cause vomiting, stupor and weakness; the sap may also cause dermatitis. The root of A. tuberosa, Butterfly Weed, is used medicinally, but overdoses are toxic.

39. Ipomoea tricolor Morning Glory

Toxicity: Lysergic acid amide, isoergine, elymoclavine and other principles. The seeds cause hallucinations if taken in large quantities. Side effects may include nausea, vomiting, diarrhea, drowsiness, numbness of extremities and muscle tightness.

40. Lantana camara Lantana

Toxicity: The fruit contains lantanine, a hepatogenic photosensitizer in animals. It is most toxic when green. In humans, withing 2-5 hours, lethargy, gastrointestinal upset with vomiting and diarrhea, dilated pupils, labored respiration, circulatory collapse and death may follow. Leaves may cause dermatitis.

41. Atropa balladonna Deadly Nightshade

Toxicity: Berries, leaves and roots contain tropane alkaloids and other toxins including apoatropine, balladonnine and cuscohygrine. May cause fever, hot, dry, flushed skin, thirst, difficulty in swallowing, burning of the throat, pupil dilation, hallucinations, confusion, convulsions, coma with subnormal temperature, respiratory failure and death.

42. Datura sramonium Jimsonweed

Toxicity: All parts, including pollen, contain the tropane alkaloid hyocyamine, atropine and scopolamine in high concentrations. Symptoms similar to A. belladonna, but slightly less deadly.

43. Solanum species Nightshade

Toxicity: The solanidan alkaloids solanine and demissine, with solanine especially concentrated in the immature fruits. May cause nausea, vomiting, abdominal pain and constipation or diarrhea. If hydrolysed by being bruised or eaten, it can cause apathy, drowsiness, salivation, paralysis, circulatory and respiratory depression, unconsciousness and death. S. pseudocapsicum, Jerusalem Cherry, sold as a potted plant for its lush foliage and bright red berries, can cause human poisoning. (Some assume these plants to be peppers, Capsicum species, but such is not the case. Potatoes, S. tuberosum, that have spoiled or turned green after exposure to the sun and the sprouts on tubers can cause severe poisoning, even death, if consumed in fairly large quantities.

44. Digitalis purpurea Foxglove

Toxicity: Leaves, seeds and flowers contain a wide variety of cardiac glycosides. Drying does not diminish the potency of the toxins. Symptoms may include various gastrointestinal problems, drowsiness, irregular heartbeat and pulse, tremors, convulsions and death. Trace amounts are used as heart medication, larger amounts are often fatal.

45. Lonicera japonica Japanese Honeysuckle

Toxicity: Known chemical components include saponin, tannin, HCN; flowers contain inositol. Soon after ingestion, severe nemesis, colic, diarrhea, pupil dilation, cold sweat, accelerated heartbeat, twitching of the limbs may be followed by convulsions, respiratory failure, coma and death.

46. Lobelia species Cardinal Flower, Indian Tobacco

Toxicity: All parts contain the alkaloids lobelanine and lobeline. May cause vomiting, weakness, tremors, sweating, rapid and weak pulse, depressed temperature, stupor, collapse, convulsions, coma, paralysis and death.

47. Ageratina altisssima (Eupatorium rugosum) White Snakeroot

Toxicity: All parts contain trematol, a complex, unstable alcohol in combination with a resin and glycosides. After a day or so of weakness, tremors, nausea, delirium, constipation, acetone odor on the breath, collapse, coma and death. In colonial times, this plant caused an illness known as "milk sickness," brought on from drinking milk from cows who had eaten this plant. This was reported as the cause of the death of Abraham Lincoln's mother.

48. Daphne mezreum Daphne

Toxicity: All parts contain mezerein, a daphnane ester. Symptoms include internal irritation with swelling of the lips and tongue, thirst, salivation, difficulty in swallowing, gastrointestinal distress, bloody diarrhea and weakness. Severe cases may show delirium, collapse, convulsions, coma and death.

49. Anthurium andraenum Anthurium

Toxicity: The leaves and stems contain insoluble calcium oxalate needles, as well as various protein toxins. Ingestion may cause a burning sensation of the mouth, throat, lips and tongue. Various types of skin rashes may also develop.

50. Helotropium arborescens Heliotrope

Toxicity: The plant contains varying amounts of pyrrolozidine alkaloids in all parts. Effects are not immediately evident. The primary toxic effects are produced on the liver. Since the alkaloids are generally excreted in 24 hours, diagnosing this plant as the cause of the illness is difficult. Other possible symptoms include damage to blood vessels and the lungs as well as headache, abdominal swelling and kidney damage.

Source: Charles E. Voigt, Vegetable Crops, University of Illinois

July 1999
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