Plant Highlight: Cycas debaoensis
By Walker Young
About the Plant
The cycads are cone-bearing gymnosperms belonging to the order Cycadales, an ancient lineage whose ancestry extends back 300 million years, to a time when flowering plants had not yet evolved. All cycads have separate male and female plants, with the cones of the two sexes differing in appearance. The living species occur in many places around the world, and they are placed in two families: Cycadaceae and Zamiaceae. The family Cycadaceae contains only one genus, Cycas, with over a hundred described species. These occur in eastern and southern Asia, Pacific islands, Australia, Madagascar and East Africa.
Cycas debaoensis is one of the Chinese species, taking its name from Debao County in Guangxi Province, not far north of Vietnam. The region’s almost surreally mountainous geography made it historically isolated, which explains why this distinctive cycad was discovered relatively recently. It is only known from a single restricted area clinging to limestone cliff walls and boulder strewn mountain ledges at elevations around 3000 feet. Humidity is high in the warm season, with the plants often bathed in fog and mist.
About the Cone and the Leaves
Though we are highlighting the plant because it has recently produced a male cone for the first time, what is truly remarkable about it is its foliage. Unlike most cycads, which have single leaflets, Cycas debaoensis sports dissected, “split” leaflets that give it a delightfully fluffy appearance. With recurving leaves sometimes over 8’ long, mature plants resemble fountains of Dr. Seussian fern/bamboo hybrid foliage. New flushes of dainty leaves unfurl in charming, fern-like fashion, and though they never hold a ton of leaves at once, healthy crowns of Cycas debaoensis provide unique architectural focal points in the landscape.
Care and Maintenance
In cultivation there has been some confusion with the closely related species Cycas multipinnata, and we are not 100% certain our plant at the garden is the true C. debaoensis, but will continue to label it as such since that’s how we received it as a donation.
We find that it tolerates full sun and our relatively scant watering, but looks lusher and more robust with a bit of afternoon shade and a more liberal irrigation schedule. Like almost all cycads, it requires very sharp drainage in our climate, and responds well to healthy doses of nitrogen to speed up growth. Anecdotal reports out of Florida suggest that its rate of growth can be maximized in a mist house, which makes sense given where it comes from. Ultimate frost tolerance is unknown in our climate, but our plant has been unfazed by short duration dips into the mid-twenties.
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