The candlestick plant, or senna alata, is a perennial shrub or tree of the fabaceae family. Originating from the tropical regions of Central and South America, these evergreen plants are a favorite among gardeners who appreciate the lush foliage and bright yellow flowers. Other common names include candlebush, candlestick senna and emperor's candlestick.
Candlestick plants have deep green foliage consisting of large pinnate leaves with oblong leaflets opposite to the vein. They can grow to 30 feet or more in height in ideal conditions. The plants are most easily identified by their tall, yellow flowers with candle-like racemes for which they are named. Candlestick plants add wonderful color to the fall garden, usually blooming from July through to the end of October.
Senna alata will grow naturally in hardiness zones 9a through 12b. They do not tolerate cold weather and will start to die off quickly as temperatures approach freezing. The plants are very adaptable and thrive in most well-drained garden soils. Candlestick plants prefer full sunlight but can tolerate partial shade. Once established, the plants are resistant to dry spells. In temperate climates, senna alata easily grows as an annual from seed.
Candlestick plants require little if any fertilizer as they are adept at extracting nutrients form most soil types. Avoid applying and nitrogen fertilizer near these plants as it will only encourage even greater foliage growth at the expense of the flowers. Senna alata grows well in slightly acidic soils so adding a few inches of mulch around the plant should keep it well fed. Water the plants periodically in the dry summer months.
Prune candlestick plants heavily in the fall after the flowers have died to prevent them from becoming messy. Tree-sized plants need to be kept in check often as they can reach 25 to 30 feet across. Shrubs can be hard pruned back to about a foot off the ground. Both trees and shrubs drop a large amount of seed and suckers will appear frequently. Remove them as they arise to keep the candlestick plant from encroaching on adjacent plants.
Pests and Diseases
Candlestick plants have very few problems with insects. They do attract plenty of cloudless sulfur butterflies, which produce voracious green caterpillars. Despite the damage caused by the caterpillars, they are best left alone as the plants quickly recover their foliage. Pesticides are not recommended as birds will soon reduce the caterpillar population. Senna alata is generally very disease resistant, and there are no specific disorders associated with this species.