Jurassic Plants

by Lori Pickering
Images © Lori Pickering

Imagine the time before the evolution of flowering plants, the time of the dinosaurs, 200 million years ago. The air is damp and smells of moist earth. The raucous cries of strange creatures reverberate through the jungle, and all around you are strange plants. What kind of plants? Jurassic plants -- Cycads.

Cycads, (pronounced si'kad), formed an extensive portion of the flora of that time, and no doubt the herbivorous dinosaurs grazed contentedly on the abundance. However, the dinosaurs disappeared, and so did l most of the cycads -- except for a few incredibly resilient species that still cling tenaciously to existence today. Now they are referred to as living fossils, for they have remained virtually unchanged, and give us a glimpse into a long-distant past.

Cycads are commonly mistaken for ferns or palms but they are actually conifers, bearing conspicuous naked cones often coloured bright red, yellow or orange, rivalling the most vibrant flower. Comprising only 11 genera and approximately 300 species (with more still remaining to be discovered) they display a remarkable diversity. Leaf size ranges from 8 inches in the diminutive Zamia pygmaea, to 23 feet in the gigantic Encephalartos laurentianus. Leaf colour varies from yellow-green, lime green, dark green, purple-green, to silver and even blue. Some cycads are arborescent (having tree-like trunks) and some have subterranean trunks that protect the plant from the ravages of the environment. Some look like palm trees, some like ferns, and some like clumps of bamboo. Longevity and growth rate also varies by species; some mature and reach coning age in only three to five years, while other, larger species take much longer and may live to be 1,000 years old.

There are many aspects of the Cycad family that are quite remarkable. One trait that is nearly unique within living seed-bearing plants is that they produce motile sperm cells called spermatozoids that must travel from the male plant to a female plant to effect fertilization. Another is their specialized up-right growing tertiary root system called coralloid roots (because they look like coral formations) which host symbiotic blue-green algae that fix nitrogen from the air. This algae produces a neurotoxin which is found in the leaves or seeds of most cycads. Species with subterranean trunks have contractile stems and roots that pull the trunks underground. Then there are the 50-pound cones that the largest species produces! These are no ordinary plants.

All these factors have earned cycads a special place in the hearts and minds of serious plant collectors. Plant hunters have scoured the globe for rare and exotic species, and installed them in botanical gardens and conservatories for over 100 years. Many rare species are extremely valuable, which has led to incidents of cycad theft and a black market on the plants. Although they once covered the entire globe (fossil remains have been found in the Queen Charlotte Islands, Alaska and the Antarctic) today their range is limited to between the Tropic of Cancer and the Tropic of Capricorn. Even these populations are dwindling, however, as they are plundered by poachers and habitat is destroyed. Today many cycad species are in danger of extinction and there is a concerted world-wide effort to conserve and protect these fascinating plants. Cycad collections in botanical gardens are a genetic resource and are being hand-propagated to relieve pressure on wild populations and satisfy the demand of collectors.

Cycads are generally very easy to grow. Their main requirement is perfect drainage, as they will develop root rot if water remains stagnant in the soil. A loose, fast-draining potting mix such a cactus mix is preferred, with a neutral to slightly alkaline soil, pH6 to 7. Terra cotta pots will help to keep the soil on the dry side and provide aeration. Fertilize with a low phosphorous (3-1-3 ratio) timed-release fertilizer including trace nutrients. All cycads benefit from a mulch, which will encourage the growth of their coralloid roots. Rain forest cycads especially are sensitive to salts in the water, so use rainwater or filtered water, if possible. Those from drier habitats are more tolerant of mineralization in the water. Some cycads prefer full sun, others shade, but always keep them oriented in the same direction (e.g., north) to keep the leaves from spiralling out of plane.

Except for the so-called Sago palm (Cycas revoluta) cycads have remained relatively unknown in Canada, although they are becoming quite popular in the United States for their architectural qualities and primitive beauty. I started Jurassic Plants Nursery to provide Canadians access to these important plants. We grow rare cycad species from seed, specially selected to be hardy outdoors in our temperate West Coast climate, or suited for indoor cultivation in the house, greenhouse or conservatory.

And, by propagating these rare plants from seed, I hope to be contributing to their conservation. As a long-term project I am growing out a cycad collection for our local Sunshine Coast Botanical Garden (still in its nascent stage, and of which I am a director), where I hope to install a Jurassic garden and bring the dinosaur era to life for visiting children and adults alike.

This article first appeared in the November/December issue of Gardens West magazine. Reprinted with permission.

Lori Pickering operates Jurassic Plants Nursery from her home on the Sunshine Coast. Lori is second Vice President and a director of the Sunshine Coast Botanical Garden Society. She gives digital slide presentations on cycads to garden clubs and other organizations.