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