Here and there around Tampa Bay, amongst the still-green trees and shrubs, you can see occasional flashes of brilliant yellow. The Christmas Cassia is in bloom, and providing a spectacular show as always!
You may know Christmas Cassia by another name; it has many, including Cassia bicapsularis, Christmas Senna, Golden Cassia, Climbing Cassia, 
Butterfly Cassia…and so on. Its current scientific name is Senna pendula – several years ago, it was shifted from the genus Cassia to the genus Senna. A little confusing, perhaps, but it didn’t change the gorgeous foliage of the plant itself!
You’ll find Christmas Cassia for sale in many local nurseries this time of year; the flowers are a great selling point. Buyer beware, though: Christmas Cassia is often sold as a small plant in pots, but it is a fast and prodigious grower. It can grow up to 12 feet by 12 feet, and it will attain that height and spread in only a couple of years. It can easily get leggy and top-heavy, so prune it to keep it bushy and strong.
This is a wonderful shrub for butterfly gardens. It serves as a caterpillar host plant for sulphur butterflies throughout the year, and the brilliant yellow flowers create “chameleon” caterpillars in the fall and winter months! Most of 
the year, the caterpillars feeding on this plant are green like the leaves. When the flowers bloom, though, the caterpillars eating them turn a brilliant yellow to match. Now that’s camouflage!
One word of caution: Christmas Cassia is native to the New World tropics and was introduced to Florida. It’s listed as a Category I invasive species by the Florida Exotic Pest Plant Council. By their definition, it is an “invasive exotic that is altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives”. However, the website Floridata notes that it generally invade areas that are already disturbed by human interference, and that its cultivation is not prohibited. If you’re a Florida native purist, avoid this cassia species in favor of a native type such as Sicklepod.
Overall, Christmas Cassia makes a great spot of color in an autumn garden. Florida’s fall foliage may be a little different than that up north, but we still get a pretty spectacular show if you know where to look!
