Northern Prickly Ash is a native deciduous shrub or small tree with attractive compound leaves, gray-brown bark, and paired sharp thorns along its branches. Small greenish flowers appear in spring before or with the leaves, followed by small reddish-brown fruits. The foliage can turn yellow in fall. It can form dense colonies, which can be useful for naturalized areas and wildlife plantings, but it may be too aggressive for a small formal garden. The branches have sharp paired thorns, so plant it well away from paths, play areas and places where people or pets regularly pass. It is very useful as a natural barrier and tolerates dry soil once established. Despite the name “prickly-ash,” it is not a true ash (Fraxinus). It belongs to the citrus family (Rutaceae).