This shrub has large elliptical leaves arranged opposite from each other on the stem. Poison ivy has three-leaf clusters growing alternately on the hairy, thornless vine. It has yellow-orange or red berries and can cause diarrhea when eaten. This plant is a member of the buttercup family. Leaves can be confused with leaves of other shrubs with edible berries. Black twinberry honeysuckle, Lonicera involucrata. red- to white-colored berries held upright. It is commonly used for fall wreaths. Another dangerous berry is the American bittersweet. Ripe berries of the poison ivy turn whitish to pale green in color 1. MANY. The berries are poisonous to humans. Okay, this is a two parter because there are just SO.