Senna bicapsularis

The butterfly bush is a semi-evergreen upright shrub or small specimen tree in the Fabaceae family native to South America, from Panama south to Venezuela and Colombia, and the West Indies. While other trees are dormant in the fall and winter, butterfly bush is showing off with bright yellow flowers that appear at a time of year when little else is in bloom. This plant is a stunning addition to any sunny landscape.

The butterfly bush generally recovers if hit by a hard frost.  When this occurs, the stems should be cut off at ground level before spring. In the spring, vigorous sprouts will emerge from the roots.  If the roots freeze, it will likely kill the plant.  Mulching around the roots helps keep the frost from killing the plants.  Frequent pinching of the young shoot tips or pruning during the growing season up to the beginning of September encourages branching and increases the number of flowers. The bush grows best in sunny locations and tolerates clay, sand, loam well-drained soils which are acidic or slightly alkaline. Needs little care once established but occasionally requires watering during periods of drought.  It has a scrambling growth habit.  If you want to keep it in check, trim it after the plant has finished blooming, to prevent it from sprawling.  Propagation is by seed or stem cutting.

The butterfly bush is a host plant for the Clousless sulpher (Phoebis sennae) Butterfly.  Before the butterflies emerge, foliage and flower buds are often eaten by the caterpillars in the fall, but these can be easily picked off by hand. They are a little elusive as the caterpillars turn green when eating leaves, yellow when eating flowers.  

Trees often fall over and will require staking to hold them upright. For this reason, it is easiest to place it in a shrub border among other shrubs that will provide support, or up against a wall or fence.  It is well worth the effort to stake a specimen tree since the tree is simply stunning in flower.  It can also be placed in a highway median since it needs little care. 

Insects, Diseases and Other Plant Problems: Foliage and flower buds are often eaten by the caterpillars of the Cloudless Sulpher Butterfly.  Otherwise, they have no serious insect problems.