Risk Assessment and Research Response of Florida-Invasive Ornamentals and Their Cultivars

Numerous assessment tools have been developed with varying intent, scope and criteria in response to the significant negative economic and environmental impacts of invasive plants on natural areas and agriculture.  Florida’s favorable climate and abundant tourism, agriculture and population foster introduction and escape of non-native plants. The University of Florida/IFAS developed a process to evaluate and rank non-native plants for invasiveness in Florida's natural areas. Called the IFAS Assessment of Non-Native Plants in Florida’s Natural Areas ("IFAS Assessment"), the purpose is to provide a well-defined, science-based mechanism by which all Florida Extension publications can consistently describe and categorize non-native plants, particularly those that are invading natural areas in Florida. The IFAS Assessment results in conclusions by species, region within Florida (north, central and south), category and category-by-region. Conclusions are used to develop Extension recommendations intended to prevent further invasion of natural areas by non-native plants. All Florida Extension publications dealing with non-native plants must include references stating the IFAS Assessment recommendations. This common basis for decisions about invasive, non-native plants will increase consistency and improve understanding of recommendations made by University of Florida personnel. The IFAS Assessment is not used for regulatory purposes.

 The IFAS Assessment consists of three parts:  status assessment, predictive tool and infraspecific taxon protocol. All plants first go through the status assessment and may be subsequently directed to the other two components. The predictive tool is adapted from the Australian Weed Risk Assessment and is used for plants recently introduced (less than 10 years for herbaceous plants and 20 years for woody plants) or not yet in Florida.

 The infraspecific taxon protocol is used for varieties, cultivars and subspecies that are expected to behave differently than the species.  This component of the IFAS Assessment was developed in response to University of Florida research demonstrating apparent sterility or reduced invasiveness of some ornamental cultivars of otherwise invasive non-native plants. Species with cultivars showing reduced invasive tendencies were butterflybush (Buddleja spp.), lantana (Lantana camara), privet (Ligustrum spp.), chinese silvergrass (Miscanthus sinensis), heavenly bamboo (Nandina domestica), fountaingrass (Pennisetum spp.), mexican petunia (Ruellia tweediana) and porterweed (Stachytarpheta spp.).

 Application of the IFAS Assessment will be demonstrated with Nandina domestica and N. domestica 'Firepower'.