Rhus glabra. Smooth sumac is a small native deciduous tree, or in less favorable conditions a shrub, with a small size of 10-15' tall and wide. It is very similar to the non-native staghorn sumac which is commonly used as an ornamental. Upright, widely branched, open in form, a small shrubby tree, suckering and forming colonies if allowed. Fruits are flashier than flowers, forming a bright crimson red, narrow fuzzy conical heads--highly ornamental but also used by various species of birds.