The popcorn plant is native to central and eastern Africa. It's a tall shrub, and in its native habitat it can grow up to twenty-five feet in height. When grown as a small shrub in colder climates as an annual, it usually doesn't get taller than three feet.
The plant's common name comes, in part, from its distinctive scent, said to be uncannily like buttered popcorn. Some people find the smell to be less pleasant, and more similar to a wet dog's fur.
The smell, oddly, comes, not from the bright yellow flowers,(which also look a bit like popped popcorn), but from the small oval leaves that run up and down its long stems. The leaves grow to about three inches long and run in pairs up and down the stem. To bring out the scent you have to run your fingers lightly across the leaves.
The plant is popular with children for its recognizable scent that must be coaxed by touching. However, since the plant is poisonous if ingested, it's best not to have it in reach of small children or curious pets.
After flowering for a long season, the plant puts out brown seed pods that are a tasty snack for songbirds.
The popcorn plant's vibrant color makes it a dramatic sight in the summertime garden landscape. It is a heat-tolerant species, well suited to hot and humid regions.
|Botanical Name||Senna didymobotrya|
|Common Name||Popcorn plant, cassia|
|Mature size||10-25 feet perennial, 2-3 feet annual|
|Sun Exposure||Full sun|
|Soil Type||Rich, fertile|
|Soil pH||Slightly acidic to neutral|
|Bloom Time||Late summer|
|Hardiness Zones||USDA 9|
|Native Areas||Central and Eastern Africa|
|Toxicity||Poisonous if ingested|
Popcorn Plant Care
Popcorn plants are somewhat invasive in their native Africa. One variety of the Senna genus can be quite weedy in some hot humid regions such as south Florida. Check the label and be sure to get Senna didymobotrya and not Senna pendula var. glabrata.
However, grown as an annual in most places, they are an attractive and interesting plant. They're fairly easy to grow in containers, but can also be planted in the garden.
With proper care, plenty of water and fertilizer, they will bloom all summer long and into the autumn, but will be at their most floriferous in the hot humid days of summer. When other plants wilt in the heat, the popcorn plant flourishes.
The popcorn plant likes heat and light, so its best to place your containers in direct sun. If the plant is getting too hot and dry, its leaves may close up during the day. They also tend to close up at night to conserve moisture.
This plant likes very fertile, rich and well-drained soils. Potting mix with some sandy loam is a good combination. Potting mix alone may drain too quickly and leave this moisture-loving plant to dry out too quickly.
Water your tropical popcorn plant regularly. Daily is probably the best bet if it's in a container. If the leaves close up during the day, that means it may be wanting some water. Keep the soil moist but not wet.
Misting the leaves with water in a sprayer is also advisable if the weather is hot and dry. You can also keep a shallow dish of water nearby to help keep it hydrated.
Temperature and Humidity
After daily temperatures fall below 80 degrees, the flowering and growth of your popcorn plants will slow down somewhat.
Popcorn plants respond well to fertilizer throughout the growing season. Fertilize in late spring and again once or twice in middle and/or late summer.
Deadheading spent blooms and trimming any dead or leafless branches will help to keep your popcorn plant looking healthy and full.
Propagating Popcorn Plants
This plant can also be propagated from seeds or cuttings, but is usually fairly inexpensive at a garden shop when purchased as an annual.
Popcorn plants can be overwintered if kept indoors. A greenhouse is preferable, but a garage is fine if the temperature stays above 40 degrees. They will only need watering occasionally.
If kept in a dark place the plant will go dormant. Bring it back outside once all danger of frost has passed and the night time temps stay above 40F on a regular basis.