Cassia is worth the search
Mississippi Gardens Newspaper and Web Column - November 10, 2003
A touch of the tropics in a landscape setting is always a pleasure, especially when it comes at an unexpected time. That's what you get with fall blooming Senna bicapsularis, which is in full bloom right now along the Mississippi Gulf Coast. Its sunny yellow tropical flowers have a lot of people wondering what it is. Senna bicapsularis has many common names including Butterfly Cassia, Winter Cassia, Butterfly Bush and Christmas Senna. Whatever it may be called, when in bloom, this plant becomes a point of special interest and the talk of the neighborhood.
Winter Cassia is one of those plants that originated in the tropics, probably South America or Africa where it freely distributes itself by seed. Somehow it made its way to the U.S. and is frequently used along the Gulf Coast and in Florida landscapes. Its official cold hardiness varies, depending on whom you ask, but I feel safe saying it is a hardy perennial in zone 8. That is, it will die back to the ground each winter in south Mississippi but will resprout each spring and grow 8 to 10 feet tall and about as wide then bloom like crazy in the fall. In tropical regions it becomes a large shrub or small tree.
Winter Cassia is probably best located among other shrubs, especially evergreen shrubs like azaleas, hollies, etc., or in the back of the perennial bed. It looks really good when used with its "feet" surrounded by small evergreen shrubs or herbaceous annuals and perennials. The reason for this is that Winter Cassia is not real showy until it blooms. And that is the entire reason for planting it.
The foliage is interesting, but not glamorous. For best floral show and plant performance situate the plant in a sunny location in well drained soil. It prefers moist, but certainly not waterlogged soil. It is also not very drought tolerant.
The fall display of flowers can be described as incredible. The golden yellow flowers are truly fantastic to look at and they attract butterflies, especially the Sulphurs of all types. These butterflies lay their eggs on the plant in order for their larvae to feed and grow. So, don't be surprised if a few butterfly larvae are found munching leaves. Blooms are also attractive to bees.
Slender brown pods that may be 6 inches long follow the blooms of Winter Cassia. Seeds can be collected and used for propagation. One source says to pour boiling water over them before attempting to get them to sprout. Cuttings are also a source of new plants.
Senna bicapsularis may not be very easy to find in the market place, but it is worth searching for. Some are available from Internet sources. If your neighbor has a Winter Cassia ask about getting some seed to start your own. Happy Gardening!
These archived columns were written by Kerry Johnson<, a hobby gardener, former weekly newspaper columnist and retired Extension Horticulture Agent for 11 coastal counties in Mississippi.