Chasmanthe Flowers: How To Grow Chasmanthe Corms

By Nikki Phipps

Image by Seán A. O’Hara

You may not have heard of them, but growing Chasmanthe flowers in the garden can make interesting specimens. Keep reading to find out how to grow Chasmanthe corms.

About Chasmanthe Flowers

Chasmanthes are winter-growing, South African natives produced from corms. They bear double ranks of arching, tubular yellow and orange flowers on tall stems and blooming takes place in summer. This genus of three species is part of the Cape Flora, a group of plants that live around the cape and nowhere else on earth.

  • C. bicolor is an early bloomer, with dark vermillion and yellow tubular flowers reaching up to 3 feet, and found along the Southwest Cape.
  • C. floribunda grows to twice the height of C. bicolor, or even more (5-6-foot plants are not unusual). From Cape Province, its flower spikes bear yellow and scarlet tubes.
  • The third species, C. aethiopica, is one of the earliest of the Cape bulbs to flower, its spikes of orange, tubular flowers providing welcome interest to the garden.

How to Grow Chasmanthe Corms

Since they’re winter growers, they need to be grown in warmer climates or in a greenhouse. In the wild, Chasmanthes grow in wet spots on rocky outcrops, where they form small colonies.

They prefer sun but will adapt easily to partial shade. Plant these in a location where the soil drains well.

Plant the corms in the spring after the last frost approximately 3 inches deep in sandy soil with the small points facing upward.

After planting, water the corms well, thoroughly soaking the area. Roots will form in the autumn. Leaves and flowers will develop in the late spring to early summer. Chasmanthes are best planted in containers in colder regions. In frost-free areas, they will multiply freely.

Chasmanthe Care

Don’t remove the foliage once blooming has ceased; the leaves provide nourishment. Water regularly, keeping in mind that these plants prefer more moisture. By late summer the leaves may yellow and die back. The foliage may be removed at this point.

Chasmanthe plants like to remain undisturbed in the same spot for years and will form large clumps. The clumps can be divided every 3-4 years, making this an easy plant to propagate. Chasmanthe grows readily from offsets. Newly planted corms may take a year to establish before blooming.

Chasmanthe can be an excellent landscape addition, requiring little attention and is pest free. The flowers are especially attractive to hummingbirds. Chasmanthes are close relatives of the watsonia and make great naturalizing plants. These tall plants have deep green leaves (about 3 feet long) and are well suited in back of mixed beds and borders where they add substance and fullness. The plants also make great flowers for cutting.