First bloom: Cyrtanthus falcatus

Cyrtanthus falcatus is a large amaryllid from South Africa. Its species name comes from its sickle-shaped leaves which recall the falcata sword favored by ancient Iberian tribes (think of a Gurkha kukri for a modern equivalent). Its flowers and its bulbs, which grow exposed at the surface, are roughly the same size and shape as those of C. obliquus which I have previously discussed, but I have found it much more difficult to flower than the latter species. After first flowering in 2017, my C. obliquus has continued to bloom every year, but this is the first inflorescence on a mature C. falcatus that I have been growing since 2014. The difference is probably due to C. obliquus being better suited to spending the winter in my heated greenhouse. C. obliquus is a lowland species, found from sea level to 1300 m in the eastern Cape northwards to KwaZulu-Natal. C. falcatus, while it also grows in KwaZulu-Natal, is a highland species found from 1100-1900 m on the Drakensberg escarpment [1]. Consequently, C. falcatus probably requires colder winter temperatures to initiate spring flowering.

I grow both plants outside in full sun during the summer and move them to the greenhouse in autumn. I bring the C. obliquus into the greenhouse before nights drop much below 50 F (10 C), but I leave the C. falcatus outside until the first frost is forecast. Although C. obliquus spends the winter on a greenhouse bench among tropical plants, I put the pot of C. falcatus on the floor where it is cooler. Usually, the plant has already dropped all its leaves and is dormant before it goes into the greenhouse. The pot remains dry all winter, and I start to water again only when I see new leaves sprouting, usually in March. The pot goes back outside in April, as soon as possible after the last frost. This winter, I put the pot right beside the greenhouse door to give it the coolest (but still above freezing) temperatures possible. That may be what finally induced flowering.

The large tubular flowers and sturdy inflorescence of C. falcatus probably indicate that it, like C. obliquus, is pollinated by sunbirds. Since birds generally prefer flowers in shades of orange and red, I was surprised by the green flowers of my plant. Most photos online do show orange flowers, but the species is apparently quite variable and green flowers are within the range of color reported for the species [1]. Since I already have C. obliquus and several smaller Cyrtanthus species that are orange, I am quite pleased with the unusual color of my C. falcatus.

Reference

1. Duncan, G., Jeppe, B., and Voight, L. (2016)  The Amaryllidaceae of Southern Africa, Umdaus Press, Pretoria, South Africa.