Plants can be aesthetically pleasing, functional, aromatic and highly desirable, but the same plants can also be deadly. Over thousands of years people have been learning how to understand and respect plants, mainly through a process of trial and error.
Although you may not know it, you may be growing plants with deadly characteristics right in your backyard. These plants may be the most beautiful plants you have ever seen, but they may also be those with the most lethal power. Knowing what is growing in your landscape is a good idea, especially if you have curious animals or small children around.
Here are five common plants that you will want to be very cautious of:
1. Iris (Iris pseudacorus, I. germanica, and related species)
Irises are perennial herbs that grow from rhizomes (or bulbs). They have very ornate flowers that have three outer spreading petals and three erect inner petals. Although a very common garden favorite, the entire plant, especially the rhizomes, is poisonous. In rare occasions, it can cause death.
There are over 200 species of Iris, most native to the North Temperate Zone. You will find several species growing wild in parts of North America, and many grown as garden ornamentals.
All parts of both wild and cultivated plants are poisonous. They contain toxic compounds thought to be an irritant resin and a glycoside. Iris plants can cause digestive pain, nausea, vomiting, diarrhea and fever. Although there are few reports of humans ever dying, there have been a number of cases where livestock have died from ingesting the plant. Parents should keep an eye on curious small children and gardeners should know that sap can irritate the skin and even cause blistering in some people.
2. Rhubarb (Rheum rhabarbarum)
Native to Siberia, rhubarb, a member of the buckwheat family, is grown all over North America for its fleshy and edible stalk. Some species are also grown for garden ornamentals. This perennial plant has large leaves, and stalks can reach up to two feet in height. Small greenish-white flowers are produced in clusters. However, if using for food, the stalks are harvested before the plant flowers.
All parts of the plant, especially the green leaf blades, contain oxalates of calcium or potassium, and oxalic acid — which are both irritant poisons. In addition, it is thought that the leaves contain anthraquinone glycosides which are highly poisonous.
Although the fleshy, sour tasting leaf stalks are commonly eaten, the leaves can cause death. There have been many cases of human poisoning reported, especially during World War I in Britain when food was scarce. It is important to note that toxins are still present even after cooking the leaves.
Symptoms of poisoning vary from person to person and usually begin about an hour after eating leaves with severe stomach pains, vomiting, weakness, fatigue, difficulty breathing, burning in the mouth and throat, and muscle twitching. In severe cases, convulsions and death may occur.
3. Calla Lily (Zantedeschia aethiopica and related species)
This showy herb has smooth, arrowhead-shaped leaves and large white-sheathed flowers. Native to South Africa, this plant is grown both indoors and also in the southern United States as an outdoor garden plant.
Calla lily is a member of the arum family and contains irritant crystals of calcium oxalate. If these are ingested, they can cause burning and swelling of the mouth and throat. In addition, the plant also contains an unidentified toxic protein. Skin and eye irritation on contact have also been reported.
4. Tulip (Tulipa spp.)
These highly popular and beautiful bulb-bearing plants have simple stems and showy, upright cup-shaped flowers in a variety of colors and forms. Native to the Middle East and Asia, there are about 60 species, with Tulipa gesneriana being the most commonly grown in North America.
The onion-like bulbs of these spring-flowering herbaceous perennials are poisonous, but not considered fatal. These highly desirable plants contain poisonous substances known as tulipalin A and B along with acylglucoside tuliposide A, which is known to be highly toxic.
Humans who have eaten the bulbs, mistaking them for onions or as a famine food, have been poisoned. Symptoms usually hit quickly after eating and include nausea, vomiting, sweating, increased salvation, compromised breathing and palpitations. Some people are sensitive to the bulbs, which can cause skin irritation.
5. Oleander (Nerium oleander)
Native to a broad section of the world — the Mediterranean region to Japan — oleander is grown as a greenhouse plant, summer patio plant or outdoors in warm regions in the southern United States. The tall evergreen shrubs have narrow, pointed leaves that have a leathery texture. Large clusters of white or pink-colored flowers make this plant a favorite ornamental in southern landscapes.
All parts of the plant, including flower nectar, are highly toxic and can cause death. In fact, oleander is the most commonly grown toxic plant found in the world and is often found planted in school yards and other places where children frequent.
Smoke from burning it and water that cut flowers are placed in are toxic as well. One leaf is lethal to humans, and eating as little as 0.005 percent of an animal’s weight can be fatal. Humans have even been poisoned from using oleander sticks for roasting food. Children are particularly susceptible to poisoning from chewing leaves or sucking the flower nectar. Honey made from the nectar is also poisonous.
Known toxins are cardioactive glycosides, which cause nausea, severe vomiting, stomach discomfort, pain, decreased pulse, irregular heartbeat, bloody diarrhea, drowsiness, coma, paralysis of breathing and even death.
A good rule of thumb is to make it a point to know the plants in your landscape and do some research before planting anything. While you can still enjoy the beauty of a variety of plants, knowing what they are capable of and the precautions to put in place is of paramount importance.
Do you know of other toxic plants? Share your thoughts in the section below: