Ornamental Invasive Plants in Florida with Research-founded Alternatives

Abstract

The ornamental horticulture industry has long been significant in its vast economic contributions to the US agricultural sector, with Florida ranking second in nursery and greenhouse plant sales. A small proportion of introduced plants eventually escape cultivation and become invasive, leaving fragile ecosystems at risk. In response, a series of propagation and production research studies have been conducted over the years to 1) evaluate the female sterility and landscape performance of cultivars and/or hybrids of ornamental invasives, and 2) develop reliable propagation systems of novel or underused natives having ornamental and ecological value. Attractive, fruitless selections of popular species such as butterfly bush (Buddleja sp.), heavenly bamboo (Nandina domestica), Mexican petunia (Ruellia simplex), lantana (Lantana strigocamara), trailing lantana (Lantana montevidensis), privet (Ligustrum sp.), maiden silvergrass (Miscanthus sp.), and fountain grass (Pennisetum sp.) have been identified as suitable non-native alternatives to the invasive or potentially invasive resident species (wild type). Simultaneously, researchers have taken a closer look at native plant alternatives that may offer similar aesthetic traits as invasive plants, while bringing added biodiversity and function for more ecologically friendly landscapes and gardens. As such, successful multisite trialing and/or propagation systems have been developed for a number of species native to Florida, such as squareflower (Paronychia erecta), coastalplain honeycombhead (Balduina angustifolia), wireweeds (Polygonella sp.), blue porterweed (Stachytarpheta jamaicensis), wild coffees (Psychotria sp.), sweet acacia (Vachellia farnesiana), and wild lime (Zanthoxylum fagara). With pronounced marketing and consumer education, it is hopeful that together sterile cultivars and native species will ultimately replace wild-type forms of commercially available ornamental invasives. This paper summarizes the current status of ornamental invasives in Florida and the role of native species and sterile non-native cultivars.