They are masters of illusion because they belie their true character with lavish blooms and bright fruits. Poisonous plants are widespread in the garden because they often present a particularly beautiful appearance. In Central Europe alone, this group includes 50 species with hundreds of varieties. Banning them completely from the planting plan would hardly be in the interest of preserving natural biodiversity. You should at least be familiar with the most dangerous poisonous plants in order not to experience any nasty surprises.
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A flexible term
The term ‘poisonous plant’ cannot be clearly defined. This is particularly due to the fact that even the smallest dose of an active substance has dangerous effects on one person, while another person can consume any amount of it without being harmed. In addition, the content of the active ingredient varies considerably from one plant to the next within the same species. Cultivation conditions, such as weather, location or the age of the plant also influence toxicity, as do its various segments, such as leaves, roots or fruits.
Regardless of this, a number of plants have emerged that can be classified as highly poisonous. Herbaceous plants, shrubs, trees and even useful plants romp about here.
The top 20 most dangerous poisonous plants
Broom (Cytisus scoparius)
The name is a bit misleading, because botanically, broom is not related to broom. In terms of habit, however, it is very similar to its famous namesake. This circumstance repeatedly leads to unintentional poisoning, because broom contains alkaloids, some of which can cause dramatic health problems. When buying a broom or using offshoots, hobby gardeners should take a close look at what they are dealing with.
The various herbs of this plant genus have long been used as medicinal herbs. For this purpose, however, they belong in competent hands. Even less than 1 gram of the fresh leaves poisons the body, makes the heart race and breath stops.
Mountain ash (rowan tree)
In the case of mountain ash, the toxicity relates to the fresh fruit – exactly the opposite compared to yew trees. Anyone who consumes them in large quantities will be punished with nausea and vomiting. In order not to expose children to this temptation in the first place, cultivation should be avoided in the family garden.
The evergreen yew species are widespread in ornamental gardens and parks. Due to various components, the bark, seeds and needles of these plants are poisonous. The small, red berries, on the other hand, do not pose a threat. Therefore, the highest safety precautions must be observed for all care and pruning measures.
Monkshood (Aconitum napellus)
The herbaceous ornamental plant with the bright blue flowers is the undisputed leader among poisonous plants. Their toxic components can be absorbed through the skin and by ingestion. In the worst case, the poisoning leads to fatal respiratory and cardiac paralysis.
Angel’s trumpet (Brugmansia)
No observer can escape the magic of its fantastically beautiful funnel-shaped flowers. Unfortunately, all parts of the plant are highly toxic. Anyone who cultivates them in the garden should never do without protective clothing including respiratory protection.
A double-edged sword, this popular garden flower. In the hands of professional chemists, the ingredients turn into a helpful heart drug. If, on the other hand, the toxins get into the hobby gardener’s body through careless maintenance work, they cause serious cardiac arrhythmias and other complaints.
Laburnum (Laburnum anagyroides)
The ornamental shrub with the yellow panicles of flowers was rightly voted poisonous plant of the year in 2012. Laburnum contains the deadly toxin cytisine in all parts, especially the seeds. Even in small amounts, this substance is deadly.
Autumn crocus (Colchicum autumnale)
The autumn crocus is a treacherous poisonous plant with a beautiful flower dress. In 2010 it made it onto the podium as poisonous plant of the year. Their resemblance to harmless wild garlic is devilish, especially when it comes to the leaves. Even in small doses, the autumn crocus causes kidney damage and respiratory paralysis.
Arborvitae (Thuja occidentalis)
The evergreen cypress family can be found everywhere in ornamental gardens and parks. Mostly used as a compact privacy hedge, Thuja not only impress with their needle-studded leaves, but also with their magnificent cones in autumn and winter. However, it is precisely these cones that are poisonous to humans and animals. In addition, the twig tips contain concentrated essential oils that make pruning without protective clothing a real pain.
Laurel cherry (Prunus laurocerasus)
The popular hedge plant is well on the way to displacing the ailing boxwood more and more. However, it should not be overlooked that the evergreen plant is poisonous in all parts. This applies in particular to the red, later black berries. It is not so much the flesh of the fruit that causes the symptoms of poisoning, but rather the seeds it contains. Whether chewed or swallowed whole, they cause abdominal pain, tachycardia and shortness of breath.
Lily of the valley (Convallaria majalis)
The striking lily of the valley with the bright white spring blossoms turns out to be a nasty poisonous plant if handled inappropriately. Leaves, flowers and fruits are equally toxic. They irritate the eyes and skin. If they get into the mouth, nausea, circulatory collapse and death occur.
Oleander (Nerium oleander)
The precious ornamental tree with the dreamy middle name rose laurel unfortunately has a virulent downside. The toxic ingredients in all parts of the plant should not be underestimated. This circumstance primarily applies to possible consumption by children or pets. The result is colicky abdominal pain and vomiting. Secondarily, skin contact should be avoided during care work, because the glycoside contained also works in this way.
Spindle tree (Euonymus europaeus)
The opulent ornamental shrub with the unmistakable bright red flowers unfortunately has a negative side: all parts of the plant are poisonous, primarily the berries. After consumption, up to 24 hours can elapse before the symptoms of poisoning suddenly manifest themselves in the form of nausea, vomiting and circulatory collapse. An important aspect for hobby gardeners is the fact that the dust thrown up during pruning can already lead to dizziness if inhaled.
The mighty, deciduous trees provide a noble wood that even surpasses the quality of oak. At the same time, they are often cultivated in large parks as a structure-forming element. In the run-up to planting, the poison content must be considered, because bark, leaves and seeds are equally dangerous. Cultivation should only be considered if it is ensured that no children or pets have access to the false acacia.
Daphne mezereum (Daphne mezereum)
This beautiful ornamental shrub with wonderful flowers in early spring has long since conquered the hearts of hobby gardeners. It should not be overlooked that it contains toxins that are extremely irritating to the skin and eyes. In addition, eating its berries in small amounts can be fatal. Daphne has no place in gardens where there are children or pets.
Belonging to the nightshade family of plants makes experienced hobby gardeners prick their ears. Closely related to the angel’s trumpet, the datura offers an equally enchanting bloom. Unfortunately, leaves, flowers, shoots, and seeds also contain the menacing scopolamine, a toxin that causes hallucinations and fever.
Smelly Hellebore (Helleborus foetidus)
This broad, bushy subshrub is often used as a picturesque underplanting for oaks, beeches and other trees. In addition, the hardy plant inhabits inhospitable, dry, gravelly-sandy locations where hardly any other plant can thrive. As long as a hobby gardener takes into account the poison content of a Hellebore, there is nothing wrong with cultivating it. Without respiratory protection, on the other hand, an agonizing urge to sneeze sets in, which can hardly be tamed.
Deadly Nightshade (Atropa belladonna)
It is one of the classics among the most dangerous poisonous plants because it takes the ignorant in two ways. On the one hand it attracts with a pretty flower, on the other hand its small berries tempt you to snack. Convulsions, delusions and death can result.
Miracle tree (Ricinus communis)
The rapidly growing spurge plant has made a name for itself as a decorative space filler with a long flowering period from August to October. Unfortunately, the seeds are extremely toxic due to the ricin content. A mere 0.25 milligrams is enough to fatally poison a person. What is particularly infamous is that the poisoning usually only becomes apparent after 2 days, when rescue is no longer possible.
Due to the latest findings, the actually harmless hydrangea joins the poisonous plants in the garden. As it turns out, the ornamental shrub emits a lethal smoke when burned. If you are disposing of clippings or the entire plant by burning, be sure to wear respiratory protection or preferably choose another form of disposal. Otherwise there is a risk of unconsciousness, impairment of the nervous system and even fatal cardiovascular arrest.
When useful plants turn into poisonous plants
Eating home-grown fruit and vegetables is one of the highlights of any hobby gardener’s work. However, no one should bite into the fruit of the bed without any worries. Under certain circumstances, even plants such as potatoes or beans are highly toxic. The details:
Apricot (Prunus armeniaca)
The apricot is a regular guest in many kitchen gardens. That’s a good thing, because the fruit contains valuable vitamins and minerals. The seeds, on the other hand, can have life-threatening effects if consumed in large quantities. In the stomach, an ingredient in the apricot kernels turns into hydrocyanic acid. As long as no more than 2 apricot kernels are eaten per day, the poison content is considered harmless.
Common bean (Phaseolus vulgaris)
The vegetable of the year 2004 should only be eaten when cooked. Raw, the pods and beans contain a toxic substance that can cause seizures, fever, and fatal shock. The poison does not dissolve by drying alone, but only in boiling water for several minutes.
Potato (Solanum tuberosum)
It is one of the most important staple foods for humans. Millions of tons of potatoes are grown worldwide every year. It is easy to overlook the fact that they belong to the nightshade family and therefore produce toxic solanine. This not only applies to all green parts of the plant, but also to tubers that turn green under light or are still unripe anyway. A single green potato is classified as harmless. Consumed in large quantities, heart problems, respiratory paralysis and nausea set in within a short time.
Black nightshade (Solanum nigrum)
If you like to grow herbs in your free time to use their healing powers, you should make a lot of ground for the black nightshade. While highly skilled homeopaths can elicit certain medicinal effects from this herb, the toxic content is considered life-threatening if used improperly. Precautions must already be taken during horticultural care work so that the skin does not come into contact with the leaves.
Tobacco (Nicotiana tabacum)
Anyone who likes to smoke a cigarette or cigar from time to time does not realize how poisonous some parts of this plant are. Hobby gardeners who grow tobacco for their own use should definitely take this into account and always work in protective clothing. In case of negligence, the punishment follows immediately in the form of dizziness, headaches, nausea and even cardiac arrest.
Tomato (Solanum lycopersicum)
Also a nightshade plant, similar concerns apply to the consumption of tomatoes as to potatoes. Green fruits are totally unsuitable for any use in cooking or eating fresh. Inappropriate use of the leaves as a tea has reportedly resulted in repeated deaths.
A large number of garden plants are naturally equipped with a more or less high poison content. In the vast majority of all ornamental and crop plants, the toxins serve as a defense against predators with benign effects on the gardener. The most dangerous poisonous plants should be considered at least in the central aspects.