Vitex rotundifolia

Vitex rotundifolia, the roundleaf chastetree or beach vitex is a species of Vitex that is native to seashores throughout the Pacific. Its range includes continents and islands stretching from India east to Hawaii and from Korea south to Australia. This woody perennial plant typically grows approximately 1 m in height. It has a sprawling growth habit and produces runners that root regularly at nodes. This rooting pattern allows the plant to spread rapidly. 

A mature Vitex rotundifolia produces fragrant, blue-purple flowers that are borne in clusters and ultimately yield small purblish-black fruits. Its leaves are rounded at the tips with green upper surfaces and silver lower surfaces. While the plant is a seashore obligate, it grows over a wide latitude range. It has been used for medicinal purposes throughout its native range. More recently, it was imported to the eastern United States where it has become a seashore invasive. Control efforts are presently underway to protect the fragile beach dune ecosystem.

Vegetative Growth

Beach vitex can reach 1 to 2 foot high and typically 12 feet in diameter, but runners can grow to infinite lengths with reports of up to 60 feet long. Stems root along their length forming a mat on the sand. Leaf arrangement is opposite. Leaves are simple, rounded, and gray-green in color with dense, grayish-white hairs on the lower surface. Leaves are 2” long by 1.5” wide. 

Problems Caused

Beach vitex (Vitex rotundifolia L.f.) is a deciduous woody vine that was introduced to the Southeastern U.S. from Korea in the mid-1980’s. Prior to its intoduction to the South Atlantic coast of the U.S., beach vitex had no history of invasiveness. However, by the mid-1990’s, dune restoration specialists with the U.S. Army Corps of Engineers, began to notice beach vitex spreading from original plantings on South Carolina beaches, crowding out native dune plants, and spreading by seeds and vegetative fragments. 
Over the past two years, the South Carolina Beach Vitex Task Force has documented beach vitex at 115+ populations along the South Carolina coast. It also occurs along the North Carolina coast, and was recently observed on a beach in Alabama. Efforts are now underway to map and monitor its spread.