Reestablishment Potential of Beach Vitex (Vitex rotundifolia) after Removal and Control Efforts

Abstract

AbstractBeach vitex is an invasive plant of coastal areas of the southeastern United States from Maryland to Georgia. Many resources have been dedicated to the control of established beach vitex stands. Successful eradication will require knowledge of this plant's ability to reestablish from seed after control efforts. To understand seed-based regenerative potential, studies were conducted to characterize the fruits and seeds, document the existence and size of seed banks, determine stratification requirements for germination, and ascertain seed dormancy mechanisms. Studies of fruit lots from three consecutive years (2003 to 2005) found that the average fruit contained 1.39 seeds, and more than 76% of fruits contained at least one viable seed. A positive correlation existed between seed number and both fruit mass and fruit diameter. A substantial soil seed bank was discovered that contained viable seeds 4 yr after vegetation removal. Stratification was required for seed germination. All stratification treatments induced germination, with highest rates realized when stratification was performed at 10 C for 8 or 12 wk. Germination rates were modestly increased (from 0 to 17%) through mild scarification in the absence of stratification. Results indicate that beach vitex has physical (fruit coat) and physiological (seed) dormancy mechanisms that are capable of delaying germination for multiple seasons, allowing development of a soil seed bank. Beach vitex can reestablish from seed after vegetation removal.