Five Common Poisonous Weeds In Your Garden

By Ray Novitske, Fairfax Master Gardener
With all the news about giant hogweed, we might think it is what we should be on the lookout for in our gardens. But, to date all the giant hogweed plants found in Virginia have been planted and cultivated by gardeners. There are other common weeds we are more likely to encounter that are dangerous.

Poison Ivy
poison ivyThis vine (Toxicodendron radicans) from the sumac family, Anacardiaceae, is very common in our area and can be very dangerous. It grows in a wide variety of places but prefers damp, partial to full shady areas. The sap or oil from any part of the plant at any time of year (even winter) causes a severe allergic reaction in most people when it comes into contact with skin or other parts of the body. It is extremely dangerous if it gets into your eyes or lungs and respiratory tract.

Poison ivy, a perennial plant, has three leaves, with edges sometimes ragged and sometimes smooth. The lead leaf contains its own petiole or leaf stem, with the other two opposite leaves directly attached to the leaf stem. The plant usually grows along the ground but can be found climbing up the side of trees and fences. In the fall, the leaves usually turn brilliant red, orange or gold and drop.

The plant spreads after birds eat the berries and spread the seeds.

Poison hemlockPoison Hemlock
Conium maculatum is an invasive non-native, biennial, flowering plant in the carrot family (same as giant hogweed.) It grows 6 to 10 feet in height with its green stems often spotted with red or purple. Leaves are lacy, fern-like and grow in small upright clusters. Flowers are clustered and white in color and develop into green deeply ridged fruit. The plant has a strange unpleasant odor.

All parts of the plant are extremely poisonous. The juice can cause skin irritation, but most poisoning occurs when people confuse the plant for wild parsnips or the leaves as parsley. The poison when ingested causes nausea, vomiting, coughing, tearing, s