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Poisonous Plants: Hellebore, Oleander, and Vinca (Periwinkle)

Diana was a member of the Royal Horticultural Society. She & her family all love gardening. She enjoys photographing & painting plants too.

Kingston Cardinal (Hellebore)

Kingston Cardinal (Hellebore)

If you didn't know that hellebores, oleander, and periwinkle (Vinca major and Vinca minor) are poisonous, this is a warning to you!

Do not be lulled into a false sense of security by thinking only a few plants are poisonous, such as foxglove, hemlock, mistletoe, and the deadly nightshade (all of which are well-known). There are actually quite a large number of poisonous plants.

1. Hellebore

Hellebores contain glycosides, variously named helleborin(e), helleborein(e) and helleborigenin(e). In common with many of the buttercup family, hellebores also contain protoanemonin in varying amounts according to the species.

The roots of all Helleborus are strongly emetic and potentially fatal. In the past, it was sometimes used to cause vomiting after poisoning, but this is now known to be harmful. Some varieties were used in the past to treat worms in children, the idea being to expel the worms by vomiting. Some varieties of worm remain in the stomach, so this treatment may sometimes have been successful. Where the worms had moved to the gut, however, it would seem that the dose would be repeated and increased, often resulting in the death of the child.

Hellebores are said to produce diarrhoea and have caused cardiac (heart) problems.

Common Names of Hellebore (Species-Specific)

  • Stinking hellebore (Helleborus foetidus)
  • Christmas rose (H. niger)
  • Fragrant hellebore and sweet hellebore (H. odorus)
  • Lenten rose (H. orientalis)
  • Purple hellebore (H. purpurascens)
  • Green hellebore (H. viridis)


Sap and Seeds From Hellebores Are Poisonous to Touch

Be very careful when harvesting hellebore seeds. It is best to wait until the seed pods dry out and then just shake them into a container or collect them from the ground.

This summer, I was myself poisoned by hellebore sap—my fingers turned black, as though badly burned. Here's how it happened:

I picked the seed pods whilst the seeds were still green and spent about twenty minutes squeezing the seeds out of the pods, so my fingers were in constant contact with the sap. I began to feel a tingling pins-and-needles feeling in my fingers and thumbs and it got so bad that I felt dizzy and had to sit down and my hands felt partly paralyzed and burning. After a few more minutes I realized what had caused the problem and ran my hands under cold water to wash away the juice. My fingers turned very red, almost purple, and were throbbing.

After 24 hours they were, if anything, worse, and I went to the doctor, who said I had done the right thing washing off the poison. She prescribed an emollient cream to rub on, and I certainly needed it. Over the next few days, the skin on my fingers and thumbs turned almost black and became so hard and chitinous that I could actually hear them scratching like a beetle when I tapped them on the table. They were burning and very painful.

Helleborus argutifolius

Helleborus argutifolius

Numerous Garden Hellebores, All Poisonous

Hellebores flower shortly after Christmas; they flower for about three months, sometimes more. The Christmas rose, Helleborus niger, is fairly low growing, with palmate leaves. Some of them are taller, up to 2 or 3 feet high. Hellebores are mostly creamy white tinged with green, sometimes with mauve or pink colours.

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They are self-seeding and propagate very easily from the seeds which form in large seedpods when the flowers have finished. Hellebores are useful plants in the garden, because they grow well in shade or half-sun, and have ornate large green palmate leaves which fill up empty spaces in winter when other plants have died back. The buds start forming in December, ready to burst forth in late winter or early spring.

Purple Hellebore (Helleborus x Hybridus)

Purple Hellebore (Helleborus x Hybridus)

This hellebore is more unusual. I must confess, I sneaked into my neighbours' front garden when they were away to take this photo—I mean, fancy going away when you have something like this coming into bloom—isn't it beautiful?

Oleander: poisonous plant

Oleander: poisonous plant

2. Oleander (Nerium Oleander)

Oleander (Nerium oleander) is one of the most dangerous poisonous plants. The whole plant is poisonous, and even water that the cut plants have stood in is poisonous. It grows wild in Mediterranean countries.

Medical Uses: Oleander contains the principal cardiac glycosides oleandrin, which can be used instead of digitalis, and neriine, as well as folinerin and digitoxigenin. The cardiovascular system may be affected by the glycosides oleandrin, oleandroside, and nerioside. The two most potent poisons are oleandrin and neriine, known for their powerful effect on the heart.

Symptoms: Oleander causes intense abdominal pain, vomiting, diarrhoea, drowsiness, dizziness, visual disturbances, rapid pulse, an irregular heartbeat and heart malfunction, often causing death. The sap in contact with the skin can cause dermatitis, blistering, irritation and soreness.

Treatment consists of inducing the patient to vomit, stomach pumping, or feeding activated charcoal in order to absorb as much of the poison as possible. The odds of surviving increase dramatically If the victim survives the initial 24 hours after ingestion.

More About Oleander Poison

Oleander poison is so strong that it can poison a person who simply eats the honey made by bees that have digested oleander nectar.

If taken internally it is deadly to humans and most animals. Cattle, sheep and goats can be killed by drinking water into which leaves of oleander have fallen.

The poisons are said to survive burning, so cooking over a fire of oleander wood is said to cause the poison to transfer via the smoke to meat being cooked. During the Peninsular Wars some of Wellington's soldiers are said to have died after eating meat cooked on skewers made from the wood.

Soldiers sleeping on oleander branches were reported to have died according to the Gardener's Chronicle in 1880.

In 1989, the Western Journal of Medicine reported the case of an 83-year old woman who attempted suicide by drinking a tea made of an infusion of oleander leaves. She suffered severe bradycardia with a pulse rate of 40 and was treated with atropine to counteract this. There are other reports in the literature of failed suicide attempts.

There are reports of a wide range of animals being poisoned by oleander, including sheep, cattle, horses, canaries, budgerigars, donkeys, a sloth and a bear. In general, farm animals sense that they should avoid contact with oleander. and, because of this, in Mediterranean countries oleander is sometimes used as a field boundary in preference to a fence.

Vinca minor (periwinkle), a poisonous plant

Vinca minor (periwinkle), a poisonous plant

3. Periwinkle

Periwinkle (Vinca major and Vinca minor) is a mildly poisonous plant. Periwinkle or vinca has small shiny leaves, and small violet star-shaped flowers in spring and then intermittently during summer and autumn.

Vinca is evergreen and low-lying and gradually spreads, so needs to be kept under control. It is a useful plant because it is good ground cover, even growing rampantly under trees. It is happy in sun or shade, but needs watering if the weather is hot and dry.

Vinca major is a close relative of oleander but is far less harmful. Eating vinca plants can cause systemic toxicity varying from mild abdominal cramping to serious cardiac (heart) complications

Medicinal use: Vinca contains a group of alka