Another plant you really want to avoid touching is the wild parsnip. These look related to the aforementioned giant hogweed, ...

The flowers of yellow jessamine are powerfully sweet in fragrance, but deadly poisonous to many animals, including humans, and not a favorite of invertebrates.

The plant may have yellow or green flowers or yellow-green berries, depending on the time of year. Like poison ivy and poison sumac, poison oak releases an oil called urushiol when it sustains damage.

In the fall, the leaves may be red or yellow. In the winter, the plant loses its leaves. However, touching the vine can still cause a rash because all parts of the poison ivy plant — from the ...