Seeds from this Mimosa Pink Tree, Persian Silk Tree, Albizzia julibrissin. Mimosa is a deciduous, small to medium-sized tree that can grow 10 to 20 feet tall. Hardy in zones 6 to 10. The bark is light brown and smooth while young stems are lime green in color, turning light brown and covered with lenticels. Leaves are alternately arranged and bipinnately compound 6 to 20 inches long, having 20 to 60 leaflets per branch. The leaf arrangement gives mimosa a fern like or feathery appearance. Mimosa flowering occurs from May through July.