Your butterfly cassia probably isn't a cassia at all

My neighbors’ butterfly cassias are all blooming now, but mine isn’t, which is very disappointing. Last year, it was a real showstopper. What could be wrong, and how can I fix it?

When you say “butterfly cassia” I know exactly what you’re talking about because I grew up calling your plant by that name, too. However, it’s not a Cassia at all, but rather a different group of plants called Senna. Study of their form, structure, flowers and molecular data indicates the two (along with another group of plants called Chamaecrista) are distinct different genera (plural for genus). You and I have to retrain ourselves and call them Senna plants.

Turns out that the difference between the two genera is important. The genus Cassia consists of about 30 tropical tree species, while Senna is the genus name of about 300 plant species, of which one is an invasive threat in Florida.

In the early 1900s, the USDA Office of Foreign Seed and Plant Introduction imported the plant we now call Christmas cassia, Christmas senna, climbing cassia or even butterfly cassia. At first all these imports, all classified Cassia, were benign additions to our gardens and our laboratories. For millennia, senna leaves have been used as a tea to help constipation. Centuries later, one species of this group, Senna pendula, has invaded our natural environment and is displacing native plant species.

The Florida Exotic Pest Plant Council (FLEPPC) regularly produces a list of plants deemed an ecological threat to the state. Senna pendula is on that list as a Category I invasive in Central and South Florida and, based on the UF/IFAS assessment lists, is not recommended in any part of Florida. Unfortunately, this is probably your beautiful plant.

Senna pendula is very common and widely used plant. After all, who can resist its clusters of showy, bright yellow blossoms on graceful arching branches? The flowers begin their show around this time of year in time for the fall holiday and are a real showstopper.

FLEPPC also publishes a list of steps homeowners should take to protect our delicate ecosystems. One step the organization recommends is to “remove invasives as soon as they are found to minimize the chance they will drop their seeds.” (https://www.fleppc.org/landowners.htm)

Before you look for your shovel (and/or flamethrower), find out for sure if yours is the offensive Senna pendula. This information from the University of Florida can help: “True S. bicapsularis (sic. the benign species) has compound leaves typically consisting of 3 pairs of leaflets and the flowers are borne on very short pedicels (stalks) — less than half a centimeter in length. In contrast, S. pendula has compound leaves with 4 to 7 pairs of leaflets, and the flowers are borne on longer (1 to 3 cm) pedicels.” (http://gardeningsolutions.ifas.ufl.edu/mastergardener/newsletter/2018/more/cassia-confusion.html)

There are two species of native plants that are better choices for a Florida-Friendly landscape than S. pendula. They are S. marilandica, alias wild senna, and S. ligustrina, also called privet senna and privet wild sensitive plant. Both grow in zone 9.

We’re considering adding a palm tree to the garden. We’re looking at smaller varieties like the dwarf pygmy date palm or Chinese fan palm. Is planting a palm the same as plant a hardwood tree? When should we plant it? How do palms do in containers?

If you’ve never grown a palm before, there are a few things you need to know.

First, palms aren't really trees. They're more like grasses. They have more in common genetically with grasses or corn than with trees. From seed, to trunk and to roots, they couldn’t be more different.

Second, all palms are not same. Some will want shade; others, full sun. Some will tolerate cold; others won’t. When you shop for your palm, know the environment of the site you’ve selected. Then pick the right plant for the that place.

Cold tolerance is also an important consideration. There are many palms that will thrive in north Florida in spite of our few and brief periods of below-freezing weather. However, there’s no guarantee that your plant is cold-hardy. Best to start by limiting your search to the palms that have proven they perform. You’ll find a list of them in the UF publication, “Palms of North Florida” (http://edis.ifas.ufl.edu/ep359) along with details about care and maintenance of these plants.

When selecting the right place, consider the soil. Palms have a shallow root system that easily penetrates our sandy Florida soil. Most palms, however, will adapt to a wide range of soils so long as the soil drains well.

The right light is also important, especially since palms differ in their light requirements. Some thrive in full, direct sun, but others need a shady garden spot. Again, the earlier mentioned publication will provide guidance.

Container-grown palms can be planted any time of the year. If yours is field-grown, wait until early summer when the soil is warm and we have frequent rainfall. Palms need to be well watered during the summer, the active growing period. Like most of our plants, palms don’t like wet feet and "well watered" doesn’t mean waterlogged.

It’s been said that 75% of palm problems are nutrient deficiencies that arise from either insufficient or improper fertilization, and not disease. Plan to fertilize your palm four times per year, using a formulation especially designed for palms. Follow the label directions carefully. It is recommended that if you can’t use the correct fertilizer, use no fertilizer at all.

Palms adapt to containers easily, though you’ll have to be attentive about proper watering, especially during warm weather when the plants are growing. Like all potted plants, potted palms will dry out quicker than those in the ground. Choose a fast-draining, yet moisture-retentive potting mix designed for containers.

Once you’ve selected your palm and brought it home, review the UF publication, “Transplanting Palms in the Landscape” (https://edis.ifas.ufl.edu/ep001). Though it’s focus is on landscape palms, the information about planting and care will be very valuable.

Paula Weatherby is a Master Gardener Volunteer with the Duval County Extension Service and the University of Florida/IFAS. For gardening questions, call the Duval County Extension Office at (904) 255-7450 from 9 a.m. to noon and 12:30 to 3:30 p.m. and ask for a Master Gardener Volunteer.