Cycadaceae and Zamiaceae

Cycads

By: George Rogers

Cycads are some 289 species in 11 genera (WH2) of ancient, flowerless, pinnate-leaved warm-climate seed plants, long pre-dating Flowering Plants in evolutionary history, and flourishing at the time of dinosaurs. About 8-10 species in 5 genera are in common cultivation (WH2). The resemblance to palms, which are flowering plants, is superficial. Cycads have cones as their reproductive structures, with the male cones resembling more or less ears of corn (although often much smaller or larger). The female cones, on separate individuals,  are variable: in Cycadaceae they look like large, loose cabbages with seeds along the edges of the modified leaves. In Zamiaceae the female cones resemble pineapples, with seeds behind the scales.

Key to Important Cycads in South Florida Landscaping

1. Leaflets with toothy or spiny margins…Dioon (consider also Encephalartos)

1. Leaflet margins not toothy…2

2. Leaflets with just one vein…3

2. Leaflets with multiple veins…4

3. Leaflets fuzzy beneath…King Sago (Cycas revoluta)

3. Leaflets hairless beneath…Queen Sago (Cycas circinalis)

4. Leaves fuzzy…Cardboard “Palm” (Zamia furfuracea)

4. Leaves hairless or nearly so…Coontie (Zamia integrifolia)

Many additional species are grown locally as specialty plants. Zamia vasquezii looks like a fern.

Cycads are Amazing (Garden Guru article, Palm Beach Post)

 

Some garden plants are museum pieces.   By that I mean they have an astounding feature beyond good looks.  For instance, how would you like a dinosaur in the yard?  Perhaps not a Brontosaurus, but maybe a green diosaur.  A Cycad is just as "Jurassic Park" as a Pterodactyl.  Cycads originated in the Carboniferous Period some 300 million years ago, eons before Flowering Plants or Mammals made their comparatively recent debuts.   By the Age of Dinosaurs was also the heyday of Cycads.   Botanists speculate plausibly that the wicked spines and poisons in Cycads are dino-repellents.  

 

Oh, sorry, what is a Cycad (SIGH-cad)?  Around our area we know them by palmy misnomers:  Sago "Palms," Cardboard "Palms," and "Gum "Palms" (Dioon), and a few additional species.  Cycads resemble Palms superficially but the latter are unrelated Flowering Plants.  By contrast, Cycads are flowerless and have seeds in cones.  The male pollen cones look ears of corn.  The female seed cones may call to mind hand grenades, or pineapples, or giant cabbages, depending on the species and on your mind.  The male cones warm up to produce repulsive vapors that drive pollen-carrying beetles out of the cones in indignant disgust.  The female cones then attract the put-upon beetles and their pollen with alluring fragrances.

 

The native Florida Cycad is Coontie.  These have had a rough history---eaten by pre-Europeans despite being toxic, milled for laundry starch, and transplanted from natural areas for landscaping.  The modern nursery industry propagates them ethically from seeds.  Coonties are tough, novel, ferny-looking, locally adapted selections appearing best when massed and well tended.  (And not clipped!)

 

Coonties grow with their tops buried ostrich-style in the sand safe from passing fires.  This trick comes from "contractile roots" that shrink and pull the crown downward into the earth.   Other Cycads have backward roots of a different type, best seen locally on Sagos where the "coralloid" roots rise upward out of the ground resembling corals on the sea floor.  These roots contain Bluegreen-Bacteria prone to convert nitrogen from the air into natural fertilizer.  More specifically, they package nitrogen as the essential amino acid glutamine used by Cycads and by body builders for bulking up protein.  Those of us with six-pack abs but no coralloid roots can hit the Health Food store for a bottle of glutamine.

 

 

Cycads are slow to propagate, although the Sagos produce readily rooted pups.  Most Cycads prefer sun or limited shade in varying degrees.  The plants are reasonably drought tolerant, but soggy roots are fatal. The Asian Aulacaspis Scale Insect introduced in the 90's on the King and Queen Sagos has been discussed to a fare-thee-well in garden columns and on the Internet.  Systemic insecticides such as Merit are favored by some, but tests of this and other systemics have sometimes been disappointing, especially on specimens in the ground.  Organic gardeners prefer dilute oil emulsions applied thoroughly and frequently.  Dioon is an alternative to the super-buggy Sago-Palms, but all good things have a disclaimer---Dioon is not entirely scale-free itself.

Every gardener should know and grow a Cycad.  Unless your hobby is spraying things, the Sago-Palms might not be the best choice.    Cardboard-Palms are rugged individuals willing to fill space, suppress weeds, and decorate your world.   And, as always, when in doubt, go native.   Try some Coonties in a well drained, filtered-sun spot where a robust ferny look might be pleasing.