Over the past couple seasons I have found myself collecting a group of plants that have fascinated me for years: cycad plants. Here is a taste of a few I’ve managed to acquire. Most are immature plants, not much more than large seedlings, but as you will see, they are indeed lovely things.
First off is the native cycad of Japan’s southern islands, Cycas revoluta v. aurea. This form is fascinating in that the leaf tips are naturally weak, hence within a month of flushing they turn from green to light yellow. This yellowing spreads down each pinnae throughout the summer and fall. Some find this lovely, while others might not. It is a very popular form in Japan and has even found its way into the international market. All forms of this species are cold hardy to at least USDA zone 8b.
Next up are all Central American species. Let’s start with the genus Ceratozamia, in this case Ceratozamia robusta. This lovely plant flushes bronze-red, but as the fronds age they turn completely green. Like all members of this genus, C. robusta grows a relatively short trunk, but can sport leaves up to 3 meters long. It is found from extreme southern Mexico and Guatemala to Belize in lowland tropical forest. All members of the genus Ceratozamia are listed under CITES Schedule I, and therefore even sending their seed across international borders is highly restricted. This species cannot endure cold and therefore is limited to USDA cold hardiness zone 9b or higher.
Another well known Central American genus is Dioon, and Dioon spinulosum is one of the more common species in cultivation. It also is the largest of the genus with trunks up to 10 meters tall. The particular plant in the photo is a form that flushes very bright yellow-green, an unusual form indeed. Being a native of southern Mexico, one cannot expect this species to survive outside of subtropical gardens. USDA cold hardiness zone 9b would be the coldest it could withstand long term.
Perhaps no genus is more characteristic of the Americas than Zamia. By far it contains the most species of any New World cycad genus and is also the most widespread, extending from Florida and the West Indies, throughout Central America, and even venturing into South America as far south as Bolivia. Most of the 50 some odd species are highly endemic, living in very restricted ranges.
This one is no exception, Zamia dressleri, an narrow endemic of Panama’s lowland forests. It falls within the “skinneri group” – named after the star of the genus, Zamia skinneri. Like Z. skinneri, Z. dressleri has large fronds with very broad, almost plastic looking pinnae. Each one can extend a meter or more with pinnae up to 50 cm long each. It is unlike Z. skinneri in that the trunk is completely subterranean and relatively small. Another difference can be seen in this photo – the new fronds flush an amazing bronze-red. Rare and sought after, this one is a true tropical plant, USDA zone 10 or higher.
Another unusual member of the genus is Zamia variegata, sometimes called Zamia picta. What makes it unusual is that the fronds typically are streaked with yellow, the only normally variegated leaf cycad species. It is a relatively small cycad with an underground stem and fronds up to 2 meters, and occasionally longer. It is relatively common in cultivation, but confined to extreme southern Mexico and adjoining areas of Guatemala. Another lowland tropical plant, preferring shade, and moist, humid conditions.
The last cycad on this photo tour is Zamia elegantissima, often confounded with Zamia fairchildiana. This plant is found in Panama and adjoining areas of Costa Rica. To make matters more confusing the plants I have are another “alba” form, that is, the new fronds flush a very pale lime green that eventually turn bright green. There is speculation that this may be yet another undescribed species. The normal form of this plant can have fronds up to 2.5 meters long and also a slender trunk to 1 meter high. My plants are seedlings yet, but they flush very pale, as can be seen in the photo.
The last photo is part of my burgeoning cycad collection. Like most rarities, cycad plants can be quite addictive once you get hooked. The tree fern at the center is the relatively rare Cyathea tomentossisima, a dwarf tree fern from New Guinea’s high mountains.