Trailing lantana (Lantana montevidensis) is a popular low-growing ornamental plant valued for its heat and drought tolerance and continuous purple or white flowering throughout much of the year. Recently, trailing lantana was predicted to be invasive by the University of Florida/Institute of Food and Agricultural Sciences (UF-IFAS) Assessment of Non-Native Plants in Florida, and therefore not recommended for use. All cultivars fall under this designation unless proven otherwise. Eight trailing lantana varieties were obtained from wholesale growers and naturalized populations found in Texas and Australia. Plants were propagated vegetatively, finished in 4-inch pots, and planted under field conditions to determine morphological and cytological differences among varieties. Australian trailing lantana differed morphologically from the other varieties in its smaller habit, leaves (which had serrate-crenate leaf margins, and fewer appressed hairs), heavy fruiting, and cold sensitivity (observational reduced growth and flowering during winter months). Nuclear DNA content analysis suggests that Australian trailing lantana is likely a tetraploid and all other varieties evaluated were likely triploids with high levels of sterility. Pollen stainability of Australian trailing lantana was moderately high (58.83%), whereas pollen production was rarely observed in all other varieties. Results support that there are two forms of trailing lantana, the U.S. varieties distinguished by their leaf and flower morphology, ploidy level, and the absence of fruit and viable pollen.

Trailing lantana [Lantana montevidensis (Spreng.) Briq.] is a low-growing, woody ornamental valued for its heat and drought tolerance and repeat blooming of purple or white flowers throughout much of the year. In 2011, trailing lantana was predicted to have high invasion risk by the UF-IFAS’s assessment of non-native plants in Florida, and therefore it was no longer recommended for use. All cultivars fall under this designation unless proven otherwise. Eight trailing lantana varieties were obtained from wholesale growers or naturalized populations found in Texas and Australia. Plants were propagated vegetatively, finished in 4-inch pots, and planted in field trials located in central (Balm) and northern (Citra) Florida. Throughout the 24-week study from June to November, mean plant quality was between 4.4 and 4.7 (on a 1 to 5 scale) for U.S. varieties and 3.9 for the Australian form. Mean flowering was between 4.1 and 4.5 (on a 1 to 5 scale) for U.S. trailing lantana varieties and 3.5 for Australian trailing lantana. Australian trailing lantana differed from other U.S. varieties tested, being smaller in size, more sensitive to cold, and having a high female fertility index (producing abundant fruit with viable seed per peduncle). Our findings indicate that some U.S. varieties of trailing lantana are unlikely to present an ecological threat and merit consideration for production and use.

No abstract

Coastalplain honeycombhead (Balduina angustifolia) is underutilised in ecosystem restoration and pollinator conservation projects. Seeds collected from different populations throughout Florida, USA during 2007 and 2016-2018 were used in experiments that evaluated the effects of a 0 or 12-hour photoperiod, seasonal and standard temperatures, 0-5,000 ppm gibberellic acid (GA) or source population (northwest, central and south Florida) on seed germination. For central Florida seeds, germination was high (62-74%) in all seasonal temperatures except for summer (4%) and was not affected by photoperiod. Germination differed for two northwest populations and was higher in warm (35/25 and 30/20°C) temperatures compared with cool (25/15 and 20/10°C) temperatures (63-72% vs. 9-36%). In a one-year move-along experiment, germination was similar at all seasonal and constant temperatures for seeds from central, south-central and south Florida, while northwest Florida seeds had reduced germination under winter temperatures. Germination of northwest Florida seeds after exposure to GA increased for two of four and three of four populations for one year and five-day old seeds, respectively. There were different temperature requirements on a regional scale and different dormancy levels at a local scale for coastalplain honeycombhead.