Despite being known for their wisdom, the ancient Greeks were fooled by cycads: They thought these seed plants were actually palm trees.
This misunderstanding began with Theophrastus, who followed Aristotle as head of the Lyceum, or philosphers’ academy in Athens, and who was also credited as the founder of the science of botany for his voluminous writings on plants and their classification. Theophrastus looked at a cycad more than 2000 years ago and thought it was a palm. Yet, hinting at its defiance of simple categorization, the word Theophrastus chose for its name was cycas, a word meaning ‘palm tree’ but in a non-Greek language.
The question arises of how Theophrastus came upon a cycad (SIGH-cad) in the first place, since cycads are not indigenous to Europe or the Mediterranean but inhabit more tropical lands, from East Asia to Africa to the Caribbean. The answer perhaps is that the Greeks had navigated the Nile River to reach tropical Africa and during the conquests of Alexander the Great had reached India, destinations whose natural landscapes include cycads.
The most popular cycad is the sago palm (Cycas revoluta), native to southern Japan, which, as we said, is not a palm at all. Actually, it’s a gymnosperm — a relative of ginkgo trees and, more distantly, of pines. There are separate male and female plants. The male sports a large strobilus that resembles a pine cone while the female cone appears as one large, fuzzy cabbage-shaped mass.
Sago is a Malay word meaning starch and refers to the spongy edible substance extracted from the pith found in the trunks of most cycad species. All parts of cycads are poisonous and thus their sago must be carefully prepared before it can be eaten. In Southeast Asia, ground cycad seeds have many uses, including cosmetics manufacture, and every now and then someone can take ill if a toxic quantity has been inadvertently applied.
There are over 300 cycad species, and many are endangered. They are found on every continent but Europe and Antarctica. There is even a cycad native to Georgia and Florida (Zamia floridana). There are types available for every nuance of Southern California climate and exposure, from balmy ocean breezes to Santa Ana winds, from full sun to deep shade. Looking for an exotic selection for planting under your oak tree? In Mexico, Ceratozamia cycads grow lush under oak trees as long as fallen oak leaves in place. These cycads appreciate acidic soil and that’s what you find under oak trees due to the acidifying action of steadily decomposing oak leaf mulch.
Most cycads grow best locally when protected from hot afternoon sun with the exception of those with silvery-blue foliage and the sago palm itself. But hot and dry weather is not a burden for many species, some of which will grow in the desert. Some are also cold hardy, tolerating freezing Antelope Valley winters just fine.
The cycad trunk grows no more than one or two inches per year. This slow rate of growth is what makes cycads so valuable. If you want to open a retirement account, I’d argue that nothing is more secure than a grove or a greenhouse full of cycads. Plant a number of cycad seeds now and when your plants are 20 years old they will be worth several hundred dollars each. If you had a thousand of them . . . well, you do the math.
As for taking care of cycads, they are extremely drought-tolerant, so treat them as you would any cactus plant. They should never need to be watered more than once a week and established specimens may go through an entire summer with no more than an occasional soak from a hose, if even that.
Cycads are heavy feeders and benefit from a balanced fertilizer such as 10-10-10, a formula indicating that 10 percent of nitrogen, phosphorus, and potassium are actively available in the product. Pearled, slow-release products are the most user-friendly since their disappearance from the soil surface means it’s time to apply them again. Another recommended practice where cycads are concerned is the application of a rich organic mulch. G&B Organics Soil Building Conditioner is typically used as a soil amendment when planting but is also highly effective as a mulch. It contains composted chicken manure, gypsum, oyster shells, worm castings, bat guano, kelp meal, and Mycorrhizae fungi.
Recently, I received a photo of a robust sago palm. The trunk diameter appeared to be one foot and the height of the specimen was probably four or five feet. However, all the leaves were yellow even though it has been receiving regular fertilization. In such cases, it is doubtful that the old leaves will ever turn green but you can impact the color of new leaves by selecting a slow-release fertilizer that is rich in nitrogen (N) and potassium (K) with a minimum of phosphorus (P). A product with an N:P:K ratio of 18:6:18 or 18:6:12 that also includes micronutrients is recommended. Application of a rich organic mulch such as the one mentioned above is also advised. Just because sago palm leaves are yellow, however, does not mean you should irrigate more often since overwatering also contributes to yellowing with this species.
Fran Grady, who gardens in Acton, has three Mexican birds of paradise (Caesalpinia mexicana) that are seven feet tall. “But I want more,” she wrote and asked how to germinate their seeds, which, like those of all leguminous plants, are found in pods.
The procedure for germinating seeds of nearly all leguminous shrubs and trees is the same. Remove seeds from their pods once pods are completely dry and have started to split open. Place the seeds in a cup and pour boiling water over them. The volume of the water should be five-to-10 times the volume of the seeds. Remove the seeds twenty-four hours later and plant.
Poinciana (poin-see-AN-na) is a drought-tolerant leguminous shrub, widely planted in arid climate zones. Mexican poinciana and the flaming orange and red pride of Barbados (Caesalpinia pulcherrima) are both encountered. They are sometimes referred to as desert birds of paradise, in homage to the magnificent plumage of their flowers and their indifference to irrigation. I have seen mature plants go an entire summer without water. Also, like all legumes, they make their own nitrate – with the help of Rhizobium bacteria that live in their root nodules – and do not require fertilization.
Plant poincianas in well-drained soil if you want them to live for more than a few years. They should be pruned hard, just before spring, to half or less of their mature, 10- to 12-foot height. Otherwise, they will get leggy and produce progressively fewer flowers each year. Leaves are bipinnate, meaning double-feathered (pinna means feather in Latin), resembling those of a jacaranda and certain ferns. Be aware that poinciana seeds and pods are highly toxic.
Tip of the Week: Maggi Carlson, from Garden Grove, wrote: “Coming from Florida, I love hibiscus. California not so much. All due to whitefly. Any ideas on how to get rid of the pests?” The good news is that the giant whitefly that takes up residence here is gradually being controlled due to release of parasitic wasps a number of years ago that are slowly getting the better of this hibiscus pest. In scanning San Fernando Valley hibiscus specimens this year, I see far fewer whitefly infested plants than previously. It makes sense that they would still be more of a problem farther south in Garden Grove since they are a tropical insect and weather is more tropical the farther south you go in the Los Angeles metropolitan area. A thick mulch of worm castings out to the drip line or outer foliage perimeter is recommended for combating whiteflies. The reason for this is that worm castings contain chitinase, an enzyme that breaks down the chitin in whiteflies’ exoskeleton. This chitinase is taken up by hibiscus roots and finds its way up into the leaves so that whiteflies sucking on them absorb the chitinase, lose their protective exoskeleton, and die. You can order worm castings at vermisterra.com.
Please send questions, comments, and photos to joshua@perfectplants.com
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