Senna articulatus, better known as candle plant, is a unique plant that combines the site needs of desert succulents with those of plants in the Brassica family (think broccoli and mustard). It has the looks of a wildflower but grows as a garden perennial in warm climates from zones 9 through 11, though it’s often cultivated as a flowering houseplant. It’s a clump-forming plant with blue-green tubular stems and small flowers arranged in characteristic fashion.
Although it’s commonly considered an annual in the Dallas area, candle plant is a durable and easy-to-grow flowering plant that blooms throughout summer to fall. It thrives in full sun landscapes and is drought tolerant. It also attracts pollinators and butterflies. The leaves of the plant are large and pinnately compound, which adds texture to the landscape.
One thing sustainability-minded gardeners will love about candle plant is that it’s a host plant for the caterpillars of the yellow sulfur butterfly. Legumes in the genus Senna usually have nectary glands in their flowers to attract pollinators, but candle plant has obligingly incorporated them into its leaves. The ant army attracted by the nectary glands near the base of the leaflets obligingly sweeps the leaves clean of the butterfly eggs and caterpillars as soon as they’re laid.
The University of Florida IFAS Extension recommends fertilizing candle plant once per month with a balanced formula during the growing season to encourage branching and yield more flowers. It’s also important to prune the plant hard in the spring in order to increase next year’s yield of flowers.