Culture
Winter hardy to USDA Zones 7-10 where it is best grown in loose, medium moisture, well-drained soils in full sun. Prefers sandy soils in coastal areas in full sun. Tolerates low fertility soils (it is native to sandy/rocky nutrient poor coastal areas). Excellent tolerance for salt, wind and drought. In the U. S., this plant is now considered to be an invasive spreader in coastal environments where it is no longer recommended for planting. It is much less of an invasive threat in inland locations where it generally grows well in dry, sunny settings.
Noteworthy Characteristics
Vitex rotundifolia, commonly called beach vitex or round-leaf vitex, is a prostrate-sprawling woody shrub that grows to 1-2' tall with an indefinite spread to 10-15' or more. Beach vitex is native to sandy coastal areas (e.g., beaches, rocky shorelines and sand dunes) in Japan, eastern Asia, Southeast Asia and India plus along the shorelines in a large number of Pacific islands. It can spread aggressively by (1) runners that root at the nodes, (2) broken stems and ripe seeds that float off to reappear at different locations along the shore, and (3) bird consumption of plant seeds that are eliminated elsewhere. Beach vitex was introduced along the North Carolina coast in the mid-1980s as a beach stabilization plant with ornamental qualities, but that introduction was soon regretted when the invasive tendencies of the plant became apparent. At this time, beach vitex is no longer recommended for planting in coastal areas in the Carolinas, with continued observation of additional introductions in Georgia, Florida, and Alabama still taking place. Broad-oblong to suborbicular leaves (to 2 1/2" long) are blue green above and light greenish-white to silver-gray below with down present on both sides. Leaves have a spicy aroma, especially when crushed. In cooler climates, leaves may fall off the plant in December leaving a tangled mass of woody stems with attached purple-black fruits. Blue-purple flowers in short inflorescences (to 3" long) bloom in May along the Carolina coast, but may flower throughout the year in areas such as Hawaii. Flowers are followed by round fruits (1/4" diameter) which mature to purplish-black. Fissured bark on older stems is attractive.
Genus name comes from the Latin name for V. agnus-castus or chaste tree.
Specific epithet means round-leaved.
Problems
No serious insect or disease problems. Plants are not winter hardy to St. Louis.
Uses
Seashore invasive that grows tamer inland where is can be used as a ground cover, soil binder or background plant.