Blooming a brilliant yellow this autumn is Florida native Senna ligustrina (SEN-nuh lig-UST-ree-nuh) – Privet Wild Sensitive Plant. Senna is a Greek word derived from the Arabic word sana, meaning tender shrub or tree. The latin word ligustrinus means privet-like. This fast-growing shrub grows in disturbed areas, forest edges and hammocks from Gilchrist County south to the Monroe County Keys and Brevard County south to the keys. Height is variable 4-6 feet and around 3-6 feet wide remaining taller than broad. Our other Florida native Senna mexicana var. chapmanii grows 2-4 feet tall and 3-6 feet wide with a broader habit. Senna ligustrina is drought tolerant and will thrive in sandy, nutrient-poor soils, but does better with some organic content.Senna ligustrina is an excellent specimen shrub for the residential landscape and can be grown in full sun or light shade. I have planted this shrub in home landscapes where it thrives with only an hour or two of direct sunlight. This plant also makes a fine choice for a large pot if you are short on space. Growth habit can vary from three to eight feet in height and remains taller than broad. Senna ligustrina can be pruned almost any time of the year, but because of frost sensitivity, winter pruning should be avoided. Senna ligustrina is considered a short-day plant. For this reason, you can expect the best flush of blooms in fall through spring when the nights are longer.
Senna ligustrina is a must-have for the wildlife garden, especially to attract butterflies. The Sleepy Orange, Cloudless Sulphur and the introduced Orange-barred Sulphur butterfly all use this plant as their larval host. Ants are also synonymous with Senna ligustrina and other Senna species. The ants are attracted to the glands at the base of the leaves called extrafloral nectaries. These glands exude a sugar-rich food source for the ants. The ants protect the plant from herbivores and will attack butterfly larvae, safeguarding the plant from defoliation. It might seem like a shame that the ants kill the caterpillars, but they are both equally important to a balanced ecosystem. Other pollinators such as bumblebees are also attracted to the blossoms. Native flowering plants are vital to helping promote pollinators and Senna ligustrina is no exception.
*There are 11 Senna species that occur in Florida and only 4 of them are native to the state, Senna ligustrina (Privet Wild Sensitive Plant), Senna marilandica (Maryland Wild Sensitive Plant), Senna mexicana var. chapmanii (Chapman’s Wild Sensitive Plant; Bahama Senna) and Senna obtusifolia (Coffeeweed; Sicklepod). The two you can find available for sale at a Florida native plants nursery are S. ligustrina and S. mexicana var. chapmanii. See my previous article on Senna mexicana var. chapmanii HERE. Be sure and avoid non-native Senna pendula var. glabrata (synonym Senna bicapsularis), a category I invasive in Florida. Common names for this invasive are Christmas Senna, Christmas Cassia and Climbing Cassia. When in doubt, always stick to our native species and Purchase your plants at a Florida native plants nursery affiliated with Florida Association of Native Nurseries. Find a native nursery in your neck of the woods by visiting Florida Association of Native Nurseries HERE.