Index of Poisonous Plants described on this page

Alsike Clover

Found in every area of Canada, this plant is adapted to a cool climate and heavy, poorly drained soil. It has been reported to cause liver damage in horses and cattle. Some symptoms with horses are blindness, depression, depression, staggering gait, cirrhosis of the liver and severe kidney problems. Additional symptoms in cattle may be laboured breathing and cyanosis. A recent necropsy on a llama in northern Washington revealed alsike clover poisoning. This is the first time that we have heard of llamas being affected by this plant, and the scary part is that the poisoning was as a result of contaminated hay.

Arrow Grass

Common in salt marshes and alkaline sloughs throughout Western Canada, it grows with rushes, sedges and slough grasses. As little as five pounds of plants could be fatal.

Azalea

This slender shrub, which contains andromedotoxin, may be nine feet tall. Vomiting, slow pulse, incoordination and paralysis are the symptoms of azalea poisoning.

Baneberry

Also known as Doll’s-eyes.
The outstanding characteristic of both White Baneberry and Red Baneberry is a stalk of berries at the top. The roots and berries contain a poisonous clycoside that causes rapid heart beat, nausea, vomiting, stomach cramps, headache, dizziness and delirium. Fatalities have been reported.

Bittersweet

The common bittersweet is a vine found in the damp soil of woods and thickets. This plant has been reported in Europe to cause vomiting, diarrhea, coma, and convulsions. Although poisoning has not been reported in North America, it should be considered hazardous.

Bleeding Heart

The western Bleeding Heart is a native to the moist, shady woods along the Pacific coast. It has clusters of pale to deep-rose flowers on leafless, reddish stems. The alkaloids present in all species make all parts of the plant toxic, but especially the soft, green or blue-green leaves, and the thick clump of roots.

Boxwood

This ornamental evergreen is widely used as a hedge, individual shrub, or as small trees. Half to three quarters of an inch long, the opposite leaves are simple, ovalish, leathery, dark glossy-green on the upper surface and lighter green or whitish beneath. The leaves and twigs have caused serious illness when eaten in large amounts. Clippings have caused stock mortality.

Bracken fern

Bracken fern is common to abundant in upland pastures, abandoned fields, and forested and burned-over areas in high-rainfall regions. Cattle that eat bracken fern often develop internal hemorrhages and other complications; death is usually caused by severe hemorrhage or secondary infection in lesions caused by consumption of the plant. Llamas love the taste of bracken fern.

Burning Bush

This deciduous shrub, which grows eight to twenty feet high, is native to the eastern United States, but is cultivated in gardens everywhere. The two- to five-inch long, opposite leaves are simple, ovalish finely-toothed, and hairy beneath. The leaves, the four-lobed scarlet fruit, and the bark have been found to be poisonous.

Buttercup

There are several species of buttercups and they are among the most common weeds. Consuming any part of the plant except the seeds produces blisters or inflammation around the mouth, irritated skin, stomach pains, vomiting, diarrhea, and jerking spasms. Irritant juices may severely injure the digestive system. Other symptoms may be temporary blindness and convulsions.

Castor Bean

The castor bean is sometimes planted to provide a quick screen or “tropical” note in the garden. It is an annual grown from seed. The whole plant is poisonous, but not the oil prepared from the seeds. The seeds are extremely toxic due to the presence of the phytotoxin ricin, which is amongst the most toxic substances known. A single castor bean seed can be fatal.

Cherry

Most parts of the Black Cherry or Wild Cherry are poisonous including the seeds, leaves, and bark. The fruit may be eaten once the seeds are discarded. Poisoning can cause such symptoms as twitching, spasms, difficult breathing, paralysis of the voice, coma of short duration, and death. Cyanide poisoning can happen suddenly and without warning. Related species of Prunus such as plum, almond, laurel cherry, cherry laurel, cherry, and peach — both cultivated and native types — may also be poisonous. Even the common apple or crab apple seeds are poisonous.

Choke Cherry

This shrub is common in Western Canada in moist draws and creek banks. It is somewhat unpalatable to stock and is taken only when other forage is unavailable and the animals are hungry. Uneasiness, staggering, convulsions, and difficulty in breathing are the first symptoms. Death follows bloating, usually within an hour of eating the leaves.

Christmas Cherry

Also known as Jerusalem Cherry.
This popular Christmas plant is related to the tomato and the fruits look like small tomatoes. The unripe (green) fruits are considered to be the most toxic part of this plant.

Christmas Rose

This garden perennial contains hellebin in the roots and leaves, which causes skin irritation. Poisonous glycosides similar to Digitalis have been reported. Symptoms of ingestion are nausea, vomiting and diarrhea with numbness and tingling of the mouth. Poisoning is usually not severe.

Crown-of-Thorns

As with many members of the spurge family (Euphorbiaceae), the milky latex sap of the crown-of-thorns may cause skin irritation. If leaves are swallowed, damage may occur to the mouth, throat, and stomach.

Daphne

Growing wild in the northeastern United States, Daphne is a cultivated plant elsewhere, and may be from one to four feet tall. It has small flowers and a quarter inch fruit that may be red or yellow. The entire plant is poisonous, but the berries are the usual offenders. It only requires a few of them to kill a child.

Deadly Nightshade

Also known as Belladonna.
Deadly nightshade is related to the potato. The poisonous chemicals in deadly nightshade are similar to those found in the green parts of potatoes. Fruits of deadly nightshade are brightly coloured and resemble tiny tomatoes, so they may be attractive to children. Children have been killed by eating only three of the berries and the whole plant should be considered dangerous due to its alkaloids which affect the parasympathetic nervous system. This is a common garden weed which prefers woods or thickets on calcareous soil or hedges near old buildings.

Death Camas

Death camas is common in Saskatchewan and Alberta, and is usually found in upland draws and depressions. The plants reach a grazable height before most grasses so are most dangerous in the spring. All parts of the plant are poisonous, especially the bulbs, which may be confused with the wild onion. A lethal dose is considered to be 2 to 2.5 pounds of the green weight of the plant per 100 pounds of body weight. Symptoms appear from one and a half hours to eight hours after eating parts of the plant. They consist of abdominal pains, nausea, vomiting, trembling, muscular weakness, struggling for breath, lowered body temperature, coma and death.

Delphinium

Also known as Larkspur.
The annual larkspurs and the perennial delphiniums comprise a genus of over 250 species of herbs from two to six feet tall. The prevailing colour of the flower is blue, while cultivated forms have other colours, as well as double blooms. Ingesting young leaves before the flowers appear is a frequent cause of poisoning. Toxicity decreases as the plants age. Later in the season poisoning comes from eating the small seeds which hold the toxic alkaloids in concentrated amounts. These plants, if eaten in quantity cause upset stomach, abdominal cramps, bloating, twitching muscles, nervous symptoms, paralysis, and death.

Devil’s Ivy

Also known as Pothos.
Toxicity of Pothos is similar to that of philodendron. Further, the clear sap of this plant may cause skin irritation.

Dumb-Cane

Dumb-canes are very popular houseplants. Eating the leaves or stems can damage the mouth and throat, making the victim unable to speak. Pets are also affected. The symptoms are burning sensations and irritation of the mouth, lips and tongue. Pronounced swelling restricts tongue movement, swallowing and breathing for up to several days. This effect is said to be due to fine crystals of calcium oxalate, but probably involves some other toxic substance as well.

Elderberry

This species may grow up to twelve feet tall with white flowers and masses of small purple or red berries. The berries are not poisonous when ripe, in fact they are sometimes used for making wine, but the roots, stems and leaves contain a cyanide-producing glycoside. Significant poisoning is unlikely.

Elephant Ears

Caladiums are grown from tubers for their lovely leaves. As with many other members of the Arum family, Caladiums contain calcium oxalate which can damage the mouth, throat, and stomach.

English Ivy

This is an extremely popular house and garden plant. The leaves and, when present, the clusters of small blue-black berries are poisonous, producing difficult breathing and coma. The saponin content of the plant may produce severe stomach pains, diarrhea, laboured breathing, and eventually coma if eaten in quantity. Serious cases have proven fatal.

False Hellebore

Also known as Hellebore, Indian Poke, White Hellebore.
This plant which may be six feet tall, has large wide leaves and greenish white flowers. It is native to moist pastures and open woods. The poisonous principle effectively lowers blood pressure and veratrum preparations are used as medicines. Symptoms of poisoning are headaches, hallucinations and burning of the mouth and throat. Salivation, shortness of breath and a slow pulse have also been reported. Very large doses cause death by respiratory depression.

Foxglove

Foxgloves are included in herbaceous borders for their spikes of white to red tubular flowers. They have become naturalized in the wild in some areas of the west. The leaves are a source of the drug Digitalis, used medicinally as a heart stimulant. Eating large amounts of the leaves can be fatal. The management of foxglove intoxication is fluid replacement for that lost by vomiting and diarrhea. Activated charcoal can be administered to diminish absorption of digitalis from the gastoenteric tract.

Golden Chain Tree

Laburnums are popular ornamental trees in the south coastal region of B.C. They are grown for their bright yellow pea-like flowers. Poisoning cases have been reported when children eat the seeds contained in pods. The seeds and flowers contain cytisine, an alkaloid similar in its actions to nicotine. Ingestion results almost immediately in vomiting, diarrhea, drowsiness, weakness, incoordination, sweating, pallor, headache, dilated pupils, and a rapid heart beat. Golden Chain poisonings are rarely serious because only small quantities of cytisine are usually ingested. Activated charcoal is an effective absorbent of this alkaloid.

Greasewood

Greasewood is found only in the southern part of Alberta and Saskatchewan on strongly alkaline flats. The buds and young leaves of greasewood contain salts of oxalic acid. The lethal dose is unknown but it appears to be quite small.

Groundsell

Also known as Ragwort.
There are about fifty poisonous species of this member of the Sunflower family, growing as a weed in pastures and meadows everywhere. Sometimes ragwort is used as a tall border plant in gardens. Stalked basal leaves are up to eight inches long, cut into lyre-shaped lobes. Stem leaves are broadly lance-shaped, up to six inches long, and cut into two or three lobes. The poisonous parts are the stems and leaves, which may cause liver damage when eaten in quantity.

Heaths

Labrador Tea, Rhododendron, Rusty Leaf, Swamp-Laurel
A number of shrubs of the heath family are poisonous to livestock. they are grouped together because they have similar growth habits distributions, toxic principles, and symptoms of poisoning. Sheep are most commonly affected, since the plants are seldom grazed by cattle unless other feed is short and since most of the localities where these plants are found are used as sheep range. Because the leaves of most of these species are leathery or bitter their palatability is rather low. Symptoms are salivation, an increased flow of secretions from the nose, convulsions and paralysis of limbs, emesis (possibly bile-stained), and dehydration.

Holly

This family is composed of many different cultivated and wild species. The black and red berries can cause symptoms such as diarrhea, vomiting, and stupor when eaten in large amounts.

Horse Chestnut

Horse Chestnuts are commonly planted as ornamental shade trees and the nuts are sometimes responsible for poisoning cases. Confusion arises because of the common name horse chestnut. This plant is not the same as the true or sweet chestnut (Castanea).

Horsetail

These plants are common in moist fields and meadows throughout Western Canada. Horses, mainly, are affected, especially by eating hay that contains much horsetail. It seldom seems to cause trouble in pastures.

Hydrangea

Hydrangea has the potential to produce cyanide, but it must be small because the symptoms of the few poisonings reported are not those of cyanide poisoning, but rather a mild gastroenteritis with nausea is the common manifestation.

Jack-in-the-Pulpit

Native to the east, the Jack-in-the-Pulpit is sometimes planted in woodland gardens in B.C. All parts of the plant are poisonous. The plant contains fine crystals of calcium oxalate and when parts are bitten, these are said to enter the mucous membrane of the mouth. The symptoms are intense burning and irritation which normally stops further ingestion so that fatalities do not occur.

Jerusalem Cherry

This ornamental, potted plant is famous for its red berries. It has a dangerous reputation and does contain possible poisonous alkaloids. It is doubtful that it causes significant poisoning.

Jimson Weed

Also known as Thorn Apple, Loco Weed, Devil’s Weed.
Jimson Weed is an annual with a stout green or purple hollow stem, which grows to a height of about three or four feet. The single leaves are coarsely toothed and are about three to eight inches long. Erect, trumpet-shaped white or pale purple flowers emerge at the forks of the stems. The seed pods are spiny capsules, about two inches in diameter, filled with numerous small, kidney-shaped, hard brownish-black seeds. Both fresh and dried leaves and seeds are sometimes deliberately ingested for their deliriant action. All parts of the plant result in poisoning if eaten and large amounts are fatal if not quickly treated. Symptoms are abnormal thirst, distorted sight, weakness, dizziness, staggering, irrational behaviour, delerium, incoherence, dilated eye pupils, and coma. Convulsions and circulatory collapse may precede death.

Labrador Tea

Glandular Labrador Tea is a low shrub with fairly thick leaves that are resin-dotted underneath, which make the herbage fragrant when bruised. The flowers are small, yellowish white, and borne in terminal clusters.
It is found mostly in wet meadows and bogs.

Laburnum

Also known as Golden Rain.
The pods and seeds on this small tree or shrub are attractive to children and have proved fatal. Vomiting is common, with nervous symptoms such as excitement and incoordination. Convulsions, coma and death due to asphyxia may occur. Usually considered highly dangerous due to its very common occurrence in gardens and parks.

Lantana

Lantanas are popular flowering greenhouse plants, or grown on the patio as a tub plant in the summer. The blue-black berries are the most poisonous part of the plant, although the entire plant is toxic. All species of Lantana are suspected of having great toxic potential.

Larkspur

Tall larkspur, a member of the buttercup family, is a tall stately perennial with stems two to six feet tall. It is common in the foothills of the Rocky Mountains and the central interior of B.C. If an animal eats as little as 0.7 percent of its weight of young plants, it will die.
Low larkspur (Delphinium bicolor) is also a member of the buttercup family and has stems up to 18 inches high. All parts of the plant are poisonous. It is readily grazed by both cattle and sheep, but sheep are seldom poisoned by it.

Lily-of-the-Valley

All parts of this popular garden plant are poisonous, but children are especially attracted to the red berries. A few cases of poisoning have been reported when children drank the water from flower vases containing lily-of-the-valley. The digitalis-like glycosides are responsible for the toxic effects on the heart.

Lily-of-the-Valley Bush

A very good friend recently lost a favourite llama to this plant and had two others that were very sick from eating a few leaves. It is also known as Japanese andromeda, the proper name is Pieris Japonica and you definitely don’t want it around your animals. It is an evergreen with shiny oval leaves but apparently it does shed its leaves. They can blow around in the fall and that could spell disaster. The leaves and nectar are poisonous, causing transient mouth burning, followed hours later by vomiting, coma, and convulsions.

Lobelia

A weed growing in cultivated and waste areas of eastern United States and Canada, Lobelia was originally dried and smoked by American Indians. All species should be considered dangerous, including those in common cultivation in gardens. The alkaloids present in all parts of the plant will produce vomiting, pain, feeble but racing pulse, paralysis, transient convulsions, weakness and coma with some deaths.

Locoweed

This species is a member of the pea family. Early yellow locoweed is low growing. The seed pods are about three quarters of an inch long and are covered with short hairs, mostly white, but a few black. Animals will become listless and passive, and exhibit irregularities in gait and eating. In the latter stages they eventually stop eating and die.

Lupine

The silky lupine occurs in fescue prairie in southwestern Alberta, and in the fescue grasslands and yellow pine zones in the interior of British Columbia. The seed and pods of lupines are the most poisonous parts, but the leaves may cause trouble if large quantities are eaten at one time. Half a pound of seeds can cause death.

Marsh Marigold

Also known as Cowslip.
The Marsh Marigold or Cowslip is usually found in the northeast and north central areas of the U.S. All of the plant is poisonous, containing an irritant oil which causes gastrointestinal irritation and diarrhea. Convulsions, hypotension and respiratory depression have been reported, but ingestion of large quantities would be necessary to produce these severe symptoms.

Mayapple

Also known as Barberry, Mandrake.
Found in woods, open fields, and pastures in southern Canada and the United States, Mayapple usually grows in groups, with plants being very close together. The unripe fruit, stems, flowers, leaves, and rootstock contain podophyllin, a resinoid which can cause symptoms of poisoning such as vomiting and diarrhea. There is little danger of poisoning unless the unripe fruit is eaten in great quantities. It is assumed that toxic effects on cell changes could result in fetal deformities if eaten when pregnant.

Mistletoe

Mistletoe is a parasitic plant whose green leaves and small white berries are popular decorations at Christmas. The entire plant is poisonous, especially the berries, which as with many other white-berried plants, are extremely toxic. Eating the berries will cause acute stomach and intestinal pains, diarrhea, weak pulse, mental disturbances, and the collapse of blood vessels. Death has occurred within ten hours after ingestion.

Moonseed

Moonseed is a woody vine with cluster of several small fruits, or drupes, which resemble grapes. It is native to eastern North America where it is found in woods and hedges, but fortunately not commonly. The key to recognizing moonseed drupes is that they have only one large crescent-shaped seed, while grapes have many seeds. Birds eat the drupes with no apparent harm, which only shows that it isn’t always safe to eat what birds eat. These drupes are poisonous, producing severe abdominal pain and indigestion. Paralysis and fatalities have also been reported.

Monkshood

Also known as Aconite, Friar’s Cap, Helmet Flower, Soldier’s Cap, Wolfsbane.
Several species of monkshood are commonly planted in herbaceous borders. There are approximately 100 species of monkshood native to the north temperate zone of the United States, Alaska and Canada. The flowers of most species are blue, but may be white, pink, or flesh toned. All parts of these plants are considered poisonous. Medical care is required for monkshood poisoning. Parasthesia and numbness are prominent symptoms, followed by weakness, convulsion, respiratory paralysis and death, sometimes within two hours.

Morning-Glory

Wild morning-glory is commonly found growing in fields and waste places throughout North America. It has poisonous seeds. Eating fifty or more seeds induces an effect similar to that of marijuana. Eating quantities of the seeds causes nausea, digestive upset, hallucinations, blurred vision, mental confusion, lack of coordination, stupor, and coma.

Mountain Laurel

This evergreen, round-topped shrub is used in gardens as an ornamental plant. The large terminal clusters of flowers are borne on sticky, hairy stems and range in colour from rose to white. Children have been poisoned by chewing on the leaves, sucking the juice from the blossoms, or by making a tea. The foliage is especially toxic. Honey, when made by bees in the area where mountain laurel is grown, has been found to be poisonous. This dangerously poisonous plant generally produces symptoms in about six hours. They consist of nausea, intense abdominal pains, vomiting, repeated swallowing, and watering of the eyes, nose, and mouth. In more severe cases breathing becomes difficult; the heartbeat is slower. There is depression, prostration, convulsions, paralysis of the arms and legs, coma, and possible death within twelve to fourteen hours.

Nightshade (Bittersweet Nightshade)

Solanum is a very large genus of plants with approximately 1,700 species. These include the Bittersweet, the Jerusalem Cherry, and the common white potato. Human poisoning from most species of Solanum is generally attributed to the immature fruit which contains the solanine glycoalkoids. Solanine has a low toxicity for adults, but there have been fatal intoxications in children.

Oak

Oak poisoning is a problem with cattle that graze on oak buds, immature leaves and acorns. It has been assumed from this that acorns are also poisonous to humans, and reports of acorn poisoning occasionally find their way into medical literature. Many people eat acorns with no apparent ill results. It is unlikely that acorns cause significant poisoning unless large quantities are consumed. Oak poisoning appears after several days or weeks. Symptoms are abdominal pains, constipation, extreme thirst and frequent urination. In severe cases there may be bloody diarrhea, rapid but weak pulse, liver damage, and death. Livestock often die within twenty-four hours after eating quantities of the young foliage and buds.

Oleander

Like lantana, oleander is grown as a greenhouse flowering plant or on the patio in tubs during the summer. All parts of oleander are extremely poisonous including vase water in which the flowers have been placed. Smoke from burning oleander leaves is also toxic. One leaf can be fatal. Apparently reports of poisoning from using oleander shoots as skewers to roast marshmallows are an urban legend.

Peach

All parts of the peach tree contain cyanide-producing compounds that are released when the peach stone kernels, the bark, and the bitter-tasting leaves are eaten. The reaction to the poisoning is rapid, showing little outward signs and causing death in less than an hour if a lethal amount is taken internally. The common symptoms that appear within minutes are gasping, overstimulation, and prostration. Changes in normal breathing and behaviour patterns are warnings.

Philodendron

Many species of philodendrons are grown as house plants. Leaves and stems may contain calcium oxalate which can damage the mouth, throat and stomach. Cats sometimes eat the foliage and may suffer irreparable kidney damage. There are many forms of philodendrons, each with different shaped leaves. One example is the "cut leaf" philodendron or Monstera. Other species such as Alocsia, Anthurium, Colacasia (Elephant Ears) and Caladium grow in warm climates of Mexico and Hawaii. Beware of the serious danger of poisoning if ingested in large amounts.

Poinsettia

There is considerable controversy concerning the toxicity of poinsettias. To be on the safe side, keep them out of the reach of children and pets. The milky latex is known to cause skin rashes on some people.

Thanks to Joyce Mizock, Executive Assistant at Paul Ecke Ranch who sent us the following note:

I happened to see your homepage and note that you include poinsettias on a list of plants that are poisonous to animals. They, in fact, are not. Check out the POISINDEX Information Service. Poinsettias are a member of the euphorbia family — some of which are poisonous, but not poinsettias. If you google “poinsettias + poisonous” you will get about 100 websites that refer you to scientific proof that poisonous poinsettias are a myth.

We are the world’s largest producer of poinsettias here at our Ranch, and in years past when we had cattle and grew in the fields instead of greenhouses, they would sometimes get into the area where we had poinsettias growing. Even though poinsettias taste horrible, they would eat the stalks with no ill effect. Occasionally rabbits get into our greenhouses now and nibble at the stock plants. Again, no dead rabbits.

A number of universities have done studies (Ohio State University for one) where they fed mice large quantities of poinsettia leaves. They only got more mice from the experiment (and none of them were dead).

Poison Hemlock

This plant resembles wild carrot or Queen Anne’s Lace. It is a naturalized weed throughout North America. The foliage is sometimes mistaken for parsley. When crushed, the leaves produce an offensive odor, which has been described as similar to mouse or cat urine. The whole plant, but particularly the root, is poisonous. It prefers to grow in wet ground, such as roadside ditches or marshy land. Poison hemlock is thought to be the hemlock used to kill Socrates.

Potato

Solanine, the poisonous principle in this plant, is found in the vines and sprouts of the common potato plant. Green potatoes, spoiled potatoes and potato sprouts have been shown to contain solanine. Gastrointestinal irritation with pain, constipation or diarrhea and nervous effects such as drowsiness, loss of sensation, weakness, breathing difficulties and paralysis with death may occur.

Privet

This is a common hedge plant in North America with blue-black, waxy berries and two-tone leaves, dark green on top and a lighter green below. Both the leaves and berries are poisonous. Symptoms are those of a severe gastroenteritis.

Rosary Pea

This is a perennial climbing plant twining around trees up to twenty feet. Originally a tropical plant, now introduced into the southern United States, it is occasionally cultivated as an ornamental plant or for its seeds. The seeds are very toxic and one seed contains more than enough abrin to kill an adult. The symptoms are at first gastrointestinal, with purging and temperature fluctuations followed by incoordination and paralysis.

Rhododendron

All parts of Rhododendrons, Azaleas and Laurels are extremely poisonous and will cause nausea, vomiting, difficult breathing, prostration, and coma. Eating a couple of leaves can be fatal for a human adult or a llama.

Rhubarb

The leaves of garden rhubarb contain oxalic acid and other toxins which can cause poisoning. The chemical composition of the leaves is considerably different from that of the edible leaf stems. The leaf blades contain dangerous quantities of oxalic acid and soluble oxalates and have caused deaths when eaten as a vegetable, even when small quantities were consumed. Vomiting, fluctuating abdominal pains and weakness precede death. As a common garden plant, the dangers cannot be over emphasized.

Rusty-Leaf

Rusty-Leaf is a medium-sized (3- to 15-feet) branching shrub with thin, alternate leaves, which have scattered rusty hairs on the upper surface. The flowers are greenish purple, rather small, and borne in terminal clusters. Grows on uplands, in moist woods.

Scotch Broom

This tall, brushy, stiffly-branched shrub of the Pea family grows to nine feet high and has bright yellow flowers. The seeds in the flat, pea-like pod, are the poisonous part of the plant.

Skunk Cabbage

This broad-leafed plant has calcium oxalate crystals in the leaves and roots, which can produce irritation and burning of the mouth and mucous membranes. Symptoms are usually not severe.

Sneezeweed

Sneezeweeds are rather coarse annual or perennial herbs found commonly in low wet meadows, along stream banks, or on mountain slopes below 10,000 feet elevation throughout North America. A few species are cultivated in gardens and grow up to six feet tall. The alternate, nearly smooth leaves are usually lance-shaped but some are as thin as grass. Daisy-like ray flowers in shades of yellow, orange, red or copper, surround the centre cone-shaped or flat-topped disk flowers of brownish tones. The poisonous substance, dugaldin, is similar in action to aconitine of monkshood, and is present in all species of sneezeweed, and extends to all parts of the plant. Sneezeweeds are among the most dangerous plants in this country to range stock and are unsafe for human consumption. The poisoning causes vomiting, weakness, trembling, rapid and irregular heart and pulse beat, laboured breathing, spasms, convulsions, and fatality.

Sour Dock

Also known as Sorrel.
This is a stout perennial herb to three feet tall, and has long been used as a potherb in Europe. The tender sour-tasting young leaves used in mixed salads, or cooked as greens, contain large amounts of potassium oxalate. Eating quantities of raw leaves has resulted in human poisoning and loss of livestock. Leaves, if cooked after one change of water, are considered safe. Oxalate poisoning may appear within two to six hours after ingesting large amounts of the leaves. Symptoms are loss of appetite, listlessness, laboured breathing, loss of muscle control, depression, coma, and occasionally death within ten hours.

Spurge Laurel

This is a deciduous shrub with a height of four to five feet which is usually grown as an ornamental plant. The leaves are single, elliptical, about three and a half inches long and three quarters of an inch wide. The flowers are usually lilac purple and appear in clusters before the leaves emerge. The fruit is scarlet and contains a pit. The whole plant is toxic. The juice of the plant is a primary irritant and produces burning and inflammation of the mouth and throat. Severe gastoenteritis occurs with vomiting and bloody diarrhea. Spurge Laurel intoxications are serious and potentially lethal.

Swamp-Laurel

Swamp-Laurel is a somewhat small (one- to two-feet) branching, evergreen shrub, with oblong, leathery, opposite leaves that are dark glossy green above and whitish underneath. The leaf margins are folded under. The flowers are small, lilac-coloured, and borne in terminal clusters.
It is found mostly in wet meadows and bogs.

Sweet Pea

This common very fragrant annual vine of the Pea family is cultivated in many varieties everywhere. Regular consumption of the seeds can cause bone deformities and paralysis of legs and arms. Wild sweet pea seeds have also proven to be poisonous.

Spindletree

The showy orange-coloured seeds have been reported as poisonous. This and other species of Euonymus are common in the garden although not all plants have berries.

Tansy

A strong-scented herb of the Sunflower family, the rather weedy plant, two to three feet high, is often used in herb gardening, but has become naturalized throughout North America. Tansy’s alternate leaves are much dissected and a dark green, while the flowers are a golden yellow. The foliage is poisonous when eaten in quantities.

Tansy Ragwort

Tansy ragwort is a poisonous plant causing unthriftiness and death to livestock by affecting the liver. Cattle can be poisoned by consuming only two percent of their body weight. Cattle and horses are most seriously affected, followed by goats. Some animals may not die, but will remain in poor shape. The condition is not reversible. Sheep are not as easily impacted by this weed and, in fact, are used in some countries as a form of biological control. Recently a friend in Washington State had some llamas with very serious liver problems believed to be caused by tansy ragwort in the hay that she had purchased. The BC Government has a noxious plant web site and there are photos of tansy ragwort along with more information. There is also a Tansy Ragwort information page on the Whatcom County Noxious Weed Control site. It turned out that the llamas mentioned above were poisoned by hay contanimated with Alsike Clover which produces similar symptoms and does liver and kidney damage.

Timber Milk-Vetch

Timber milk-vetch is a member of the Pea family and has the characteristic pea flower and pod. Four or five pounds of the plant will produce signs of poisoning. With cattle, death does not usually follow poisoning and most animals recover slowly.

Tomato

The annual garden tomato belongs to a group of from ten to twelve species, all of which are closely related to the deadly nightshade. For centuries the fruit was thought to be poisonous and it was planted in gardens as an ornamental. Although we now know that fresh tomatoes are harmless, the foliage and vines contain alkaloid poisons. Children have been severely poisoned from making a tea from the leaves, and livestock have died from eating the foliage and vines. Digestive upsets consist of nausea, vomiting, abdominal pains, constipation or bloody diarrhea. Nervous effects are sluggishness, abnormal flow of saliva, laboured breathing, trembling, weakness, loss of feeling, and paralysis.

Water Hemlock

Water hemlock is native to the east, but is occasionally planted in bog gardens. All parts of the plant are poisonous, but the roots resemble wild parsnips, so are the usual cause of poisoning. One mouthful of the rootstock is sufficient to kill a grown man. These plants grow only in wet or swampy areas. The cicutoxin acts directly on the nervous system, usually within thirty minutes to produce salivation followed by violent convulsions which distort the body and cause grinding or clamping of the teeth. There is dilation of the pupils and delerium. Abdominal pain and vomiting commonly occur. Death occurs due to paralysis and respiratory failure. It should be considered very dangerous.

White Baneberry

This is an herbaceous perennial occasionally planted in woodland gardens. The white fruits of baneberry are extremely poisonous. The red fruits of Actea rubra are also poisonous.

White-flowered Rhododendron

White-flowered Rhododendron is a medium-sized shrub with thin, clustered leaves. The flowers, one to three in a cluster, are showy, pale yellow, bell-shaped, and about one inch across.
It is usually found on uplands, in moist woods.

Wisteria

Wisterias are vines planted for their beautiful pea-like flowers. The seeds, borne in pods, are known to be poisonous to children. Seeds ripen in late summer. As with Laburnums, pods found within easy reach of children should be removed. The flowers are toxic and serious intoxications have resulted from chewing the bark. Two seeds are enough to cause serious danger to the health of a child.

Yew

The yews are evergreen trees and shrubs with alternate branches. The bark is reddish-brown, thin and scaled. The flat, needle-like leaves, about one inch long, grow in opposite pairs along the twigs. The hard green to black seeds are exposed in a fleshy red cup (aril). The needles and seed of yews are poisonous. Children may be attracted to the red, sweet-tasting berries. While the berry flesh is not toxic, the seeds within are extremely poisonous. Not all plants bear fruit. The management of yew poisoning includes evacuation of the stomach followed by the oral administration of activated charcoal with water.

Brian and Jane Pinkerton
29343 Galahad Crescent
Mount Lehman
British Columbia
Canada V4X 2E4

Phone: 604-856-3196
E-mail address: brianp@smartt.com