Poisonous Ornamental Plants 1/2

In short: Jimsonweed, oleander, Japanese yew and eastern arborvitae are common garden ornamentals that are toxic in almost all of their parts. Two ingested oleander leaves can kill an adult and one may be enough for a child, while yew poison acts within tens of minutes. Seek medical help immediately after any ingestion.

Ornamental plants have become an integral part of our gardens, but some of them are poisonous and can pose a potential danger, especially if small children are around. Very commonly grown and at the same time highly poisonous plants include jimsonweed, oleander, Japanese yew, and western thuja. These plants are poisonous in their entirety or almost entirely, and ingesting even a small piece can cause death if medical help is sought too late. Be especially careful when growing these plants so that they only beautify your garden and do not cause a catastrophe.

Jimsonweed

Jimsonweed (lat. Datura stramonium) belongs to the nightshade family (lat. Solanaceae). Jimsonweed is a highly poisonous plant that can cause death in higher doses. The toxicity of jimsonweed is caused by the content of alkaloids such as atropine, scopolamine, and hyoscyamine. All parts of jimsonweed are highly poisonous. Intoxication manifests itself through increased mobility, anxiety, feelings of terror, temperature rise, dry mouth, dilated pupils, rapid heartbeat, dizziness, staggering gait, confusion, disorientation, and hallucinations. After the intoxication peaks, a very rapid depression follows, manifesting in hard sleep, exhaustion, and irritability. After ingesting any part of jimsonweed, it is essential to call for medical help immediately. With timely intervention, the survival prognosis is quite high (approximately 90%), but extreme caution is still necessary, especially if children can get near the jimsonweed.

Jimsonweed and Its Cultivation

Jimsonweed is an annual plant that can grow to a height of about 0.5 – 1 meter. The flowers are trumpet-shaped, white or light purple in color, and fully open in the evening. The fruit is a spiny capsule containing a large number of black seeds. Jimsonweed thrives best in nitrogen-rich humus soils in sunny or semi-shaded locations. It prefers moderate watering.

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Interesting Fact

The well-known "angel's trumpets" are often referred to as durmans (lat. brugmansia) and jimsonweed (lat. datura) as daturas. However, these two plants differ fundamentally. The difference is that daturas are annuals and "angel's trumpets" are perennial plants.

Oleander

Oleander (lat. Nerium oleander) is another highly poisonous plant that is often found in our gardens. The entire plant is poisonous – leaves, stems, and flowers. Oleander is even considered one of the most poisonous plants because just two ingested leaves can kill an adult, and a child may need only one. Even honey produced by bees from oleander is poisonous. Oleander contains glycosides oleandrin and nerin, which directly affect cardiac function. Intoxication manifests with vomiting, fever, tremors, dizziness, convulsions, and cardiac arrhythmia. As with ingestion of any other poisonous plant, it is necessary to seek medical help as quickly as possible so that an antidote can be administered.

Oleander and Its Cultivation

Oleander is an evergreen shrub that grows up to 2 m in height. The stem branches abundantly. Oleander leaves are leathery and elongated in shape. Flowers can be white, red, pink, or yellow. Some cultivars have double flowers. Oleander is a perennial plant that is not frost-resistant, so it must be moved to winter quarters before the onset of frost. For oleander to thrive well, it needs outdoor summering and overwintering in a cooler environment. In summer, abundant watering with settled water is important (note: oleander is sensitive to water hardness), while in winter, watering should be reduced according to room temperature. In cool conditions, water only enough to prevent the root ball from drying out completely. If you cannot provide cool overwintering for your oleander, at least spray it regularly. Summer oleander in a warm, sunny location and provide regular fertilization.

Interesting Fact

The rarest type of oleander is the one with yellow flowers; it was bred most recently and is still not very widespread among growers.

Japanese Yew

Japanese yew (lat. Taxus cuspidata) belongs to the yew family (lat. Taxaceae). The entire plant except for the red fleshy aril surrounding the seed is highly poisonous. The danger lies in the content of alkaloids – such as taxine A, taxine B, lycopene, and ephedrine. Do not eat yew berries at all and make sure children do not taste them – the seed inside the aril is highly poisonous. The poison begins to act very quickly, so it is essential to seek medical help as soon as possible and undergo gastric lavage. Otherwise, death can occur within tens of minutes after ingesting the poisonous part of the plant. Intoxication causes slowing of cardiac activity to the point where it can cause cardiac arrest.

Yew and Its Cultivation

Japanese yew is a densely branched tree that can grow up to approximately 10 m in height. It thrives best in sunny locations, but tolerates partial shade and shade as well. It does not prosper in waterlogged soil or excessively windy locations. Yews are undemanding in terms of nutrients. If you plant it in calcareous soil, you'll be doing the right thing. Yew is the only coniferous tree that can be pruned without damage; more radical pruning is best done at the end of June. Another advantage is that yews tolerate polluted urban air well, which is why they are often planted in parks. Next time you go for a walk there, teach children that they should avoid yews and that the red "berries" are not sweets.

Eastern Arborvitae

Eastern arborvitae, better known as eastern white cedar (Latin: Thuja occidentalis), is another poisonous tree that is very commonly found in gardens. Unlike yew, the toxicity of arborvitae is not as well known and this information comes as a surprise to many. Toxins are contained throughout the entire plant, with the highest concentration in young shoots and needles. Arborvitae contains essential oils of toxic thujone, pinene, tanacetone and other substances. Toxicity is mainly caused by thujone, which irritates the skin and after ingesting any part of the arborvitae causes vomiting, bloody diarrhea, damages the kidneys, and in pregnant women can lead to miscarriage as a result of pelvic congestion. Poisoning manifests as convulsions, general weakness to unconsciousness, and in case of severe overdose and failure to seek medical help, it can even result in death.

Arborvitae and Its Cultivation

Eastern arborvitae is an evergreen tree that can grow up to 20 m in height. Thanks to its conical growth habit, it is often used as a living hedge. The main potential danger comes from the small cones growing at the ends of twigs, which attract small children to taste them. Arborvitae are very hardy woody plants that tolerate sun, partial shade, and shade well. They thrive best in moist, clay-sandy soils. They also tolerate calcareous soils well. You can support the growth of arborvitae with regular fertilization during the summer period; do not fertilize arborvitae from autumn onwards so they can rest and prepare well for winter. If you want to shape arborvitae into a living hedge, trim them once a year from May to the end of August. In the first and second year after rooting, only the tips are trimmed; from the third year onwards, arborvitae can also be shaped from the sides.