Popcorn plants? No kidding!
Senna didymobotrya, a shrub from tropical Africa, has scented foliage that when rubbed or brushed smells like buttered popcorn, thus its common name “the popcorn plant.”
Because of this unique fragrance, it has become a novelty for many gardeners. Certainly this year it has been the novelty at my garden not only for its fragrance but also for the long blooming flower racemes.
Each flower raceme produces 20-30 glossy, dark brown flower buds. These buds open into buttery yellow, five-petal flowers with curved stamens. Since the flowers continue to develop from the bottom toward the top, the entire raceme inflorescence can reach a foot tall or more; a branch with four of these racemes looks like a fancy candelabra, which gives it another common name: the candelabra plant.
Although hardy to zones 9-11, it is commonly used in cold climates as a horticultural or seasonal annual because of its rapid growth and early flowering.
This legume prefers to grow in full sun, in moist and well-drained soil. To sustain the popcorn plant’s rapid growth, plenty of water and fertilizer must be added regularly.
In its natural habitat it may reach 25 feet tall, but when grown as a seasonal annual, it will grow to 2 to 4 feet tall.
The large feathery foliage of this plant adds a different texture and tropical look to the garden.
Its compound leaves can reach up to 18 inches long and the leaflets tend to close at dusk — almost looking as if it is going to “sleep.”
Particularly, I like the green and leathery leaflets on the light green rachis (the stem where the leaflets are), because they provide a rich texture and contrast against other plants in the garden.
This plant blends wonderfully with other large, tropical foliage like elephant ears, bananas, and cannas, although it could blend easily with some pink cosmos or even dahlias.
I got my popcorn plant at a local garden nursery early in the spring, and it already had flowers that right away added a bright spot as an accent plant.
Some of the flowers have developed into typical green legume fruit pods that turn brown. Each pod can produce up to 16 seeds.
Since this is the first year that I grew this plant, I still have not tried to germinate the seeds; in some garden books it is suggested to store them and germinate by soaking for 24 hours in water or to scarify or boil in water.
Once seedlings are established, it is important to remember that these plants can only go outdoors once all danger of frost has passed — about the same tie you put tomatoes out.
The popcorn plant could be overwintered indoor in a greenhouse or by a sunny window, and it should be brought indoors before the first hard frost.
I do not plan to overwinter it — I want to see how it changes in the fall and if it adds any other interest to the garden.
As I write this article, my popcorn plant is 36 inches tall, it has 6 "candles" and is developing two new branches. I am wondering if toward the end of the season, with these eight to 10 new buttery yellow racemes, it will look like an intricate Victorian candelabrum.