Debuting golden yellow flowers when many other plants have ceased blooming, popcorn cassia is a welcome addition to the late summer and fall landscape. Popcorn cassia is easy to grow as an annual or perennial. In tropical regions, it will form a multi-stem shrub. Native to Africa, this plant gets its common name from the scent of its foliage that gives off the scent of buttered popcorn when rubbed. It is a colorful and welcome addition to both tropical and temperate landscapes. Its flowers attract butterflies, insects, and birds feeding on the nectar.
The plant is toxic to humans and pets.
Popcorn Cassia Overview
Where to Plant Popcorn Cassia
If you live in hardiness zones 9-11, you can grow popcorn cassia as a perennial or multi-stem shrub. Plant it in full sun and well-draining soil with a neutral pH. Whether you plant it in a landscape beds or alongside other shrubs, give it room to expand. It is a great plant for adding interest to a lackluster corner of the landscape or anchoring an island planting in fall. In warm climates, popcorn cassia is particularly striking when planted alongside banana or other plants with dark green leaves.
In cool climates, enjoy popcorn cassia as an easy-to-grow annual in containers.
How and When to Plant Popcorn Cassia
Plant popcorn cassia after all danger of frost is past. For a potted nursery plant, dig a hole that is about 1.5 times as wide as the pot and has the same depth. Place the plant in the hole and backfill with the original soil. Tamp it down and water it immediately. Keep watering the plant until it is established.
You can also plant popcorn cassia from seed, either directly outdoors or indoors (see How to Propagate Popcorn Cassia below).
Space plants 2 feet apart. If you live in zones 9-11 where popcorn cassia is grown as a perennial, staking is helpful.
Popcorn Cassia Care Tips
Light
Popcorn cassia needs full sun to thrive.
Soil and Water
The soil should be rich, moist, and well-drained, with a pH in the neutral range (6.6 to 7.5).
In the absence of rain, water the plant regularly.
Temperature and Humidity
In hot and humid weather, the plants grow quickly and unfurl many new leaves and flower stems. But when temperatures fall below 80 degrees F, the growth slows down significantly. Popcorn does tolerate a light frost.
In cold regions, overwinter it indoors in a greenhouse or a bright window. Bring the plant inside when nighttime temperatures are in the high 30s.
Fertilizer
The plant does best in rich, fertile soil so if the soil is poor, amend it with organic matter and fertilize with a complete, balanced fertilizer a couple of times during the growing season.
Pruning
Pruning, if at all, is done after plant has finished blooming. You can prune it lightly for a more compact growth; however, this might delay a repeat blooming.
Potting and Repotting Popcorn Cassia
Popcorn cassia does well in a container. Choose a container that has large drainage holes and is about 4 inches larges in diameter than the root system to allow for future growth. Because the plant gets quite tall, placing some pebbles or rocks at the bottom of the container adds to the stability of the pot so it does not topple over easily. Fill the container with well-draining potting mix. Container-grown plants require more frequent watering, on hot summer days at least daily, and also more fertilization.
Pests and Problems
The plant does not have any significant pests or disease issues. Poorly drained soil can lead to root rot. Deer usually leave it alone, too.
How to Propagate Popcorn Cassia
You can start popcorn cassia from seed or propagate it with a rooted cutting. Seeds will germinate more readily when soaked in water for 24 hours. Sow seeds shallowly indoors in February or March and wait until all danger of frost has passed before planting the seedlings outdoors.
Popcorn Cassia Companion Plants
Elephant's Ear
In a warm climate huge blue-green leaves and bold vein patterns of elephant ears form an appealing contrast to the bright yellow flowers of popcorn cassia. It grows up to 8 feet tall. Zone 10-11
Dahlia
Amplify the bold yellow flowers of popcorn cassia by pairing it with orange and magenta dahlias, Dahlias are hardy in warmer regions, but can be saved year after year in colder areas by digging up the tubers in the fall and replanting them in the spring. Zone 8-10
Verbena
Just like popcorn cassia, purpletop vervain (Verbena bonariensis) can be grown as an annual or a perennial, depending on the climate. It is a tall, purple-blooming prairie-type verbena that happily reseeds in the garden. Zone 7-9
Frequently Asked Questions
- Is popcorn cassia invasive?Popcorn cassia is not considered invasive but there is a look alike, another member of the Senna genus (Senna pendula var. glabrata) that is an invasive plant in central and south Florida. It has the potential to spread to wild areas, displacing native species. When purchasing popcorn cassia, make your purchase from a reputable nursery and carefully check the plant tag before buying to ensure it is Senna didymobotrya.
Popcorn cassia is not considered invasive but there is a look alike, another member of the Senna genus (Senna pendula var. glabrata) that is an invasive plant in central and south Florida. It has the potential to spread to wild areas, displacing native species. When purchasing popcorn cassia, make your purchase from a reputable nursery and carefully check the plant tag before buying to ensure it is Senna didymobotrya.
- Is popcorn cassia edible?No, it is not edible; in fact, the plant it toxic to humans and pets.
No, it is not edible; in fact, the plant it toxic to humans and pets.