The Whitethorn Acacia is a slow growing, long lived shrub or small tree that matures to a height of 10 to 20 feet tall and wide. Stems are reddish purple. Young plants have inch long white thorns, although older branches are often thornless. It has yellow fragrant puffball flowers that appear in late spring and in late summer with sufficient water. This tree attracts birds and other wildlife and adds nitrogen to the soil.