Popcorn cassia (Senna didymobotrya) is a showy tropical accent plant.
Ginger E Long, © 2023 HGIC, Clemson Extension
Last October, while driving along Main Street in uptown Greenwood, SC, I spotted a large plant with tall golden flower spikes. It was so fantastic that I made a U-turn to check it out. The plant was popcorn cassia (Senna didymobotrya). It is native to Africa and is often used as a cover crop.
Popcorn cassia is an annual plant in the Legume family that is sometimes called the candelabra tree or peanut butter senna. The common names describe the flower spikes and the scent of the plant. The leaves, when crushed, smell like popcorn, and the flowers have a slight scent of peanut butter.
Flower spikes appear in the summer and last through fall. The spikes have dark brown buds that open to golden-yellow blooms. Flowers open at the bottom of the spike first, then gradually open to the top. The flowers attract butterflies, bees, and other pollinators.
The flower spikes of popcorn cassia can reach 12 inches tall.
Ginger E Long, © 2023 HGIC, Clemson Extension
The plants grow 6 to 8 feet tall and wide. The large leaves are pinnately compound, meaning they have leaflets on either side of the central leaf petiole. Each leaflet is 2 to 3 inches long, and the whole leaf can reach 18 inches in length. When grown in a container, the overall size of the plant will be much smaller.
Popcorn cassia grows quickly in the heat of summer. Plant it in a sunny location with at least 8 hours of sun. The soil should be high in organic matter and well drained. Fertilize the plants regularly for more flowers. It requires regular watering. Cut it back after it flowers to keep the plant bushy. These plants are rarely browsed by deer.
You can find popcorn cassia as small plants in garden centers in the spring and summer. It can also be grown from seed. Check with your local garden centers for availability. When not available locally, plants and seeds can be purchased online.
For more information on annuals, see HGIC 1152, Growing Annuals.
