The vitex, or chaste tree is a small tree or a very large shrub, depending on water and climate, and is cold hardy to the Texas Panhandle. Low water-use once established, it can grow well in higher water zones. It is called the summer lilac because of the similarities of its flowers to the lilac shrub. Vitex varieties can be found in blue, lavender, and pink fragrant flowers. The leaves are similar to those of the marijuana plant. Vitex will sucker, especially when given ample water. It is native to southern Europe and Western Asia.