Plant of the Week
Sago Palm
Latin: Cycas revoluta
On a recent foray to the sunny South, I was able to renew my acquaintance
with palms. Like most northerners I have only a nodding familiarity with palms,
but one - the Sago Palm - I find especially intriguing because it masquerades as
a palm but in reality is more closely related to a pine tree.
When the world was young and fossil fuels were being deposited in the ancient
bogs of Pangea, the botanical tree of life branched. The new side shoot was at
first spindly and struggled for survival, but eventually this new sprout - 19th
century botanists later called them angiosperms - went on to dominate the flora
of the modern world.
The main trunk of the tree of life did not wither and die but lost its
preeminence in the botanical kingdom. These more ancient plants - the
gymnosperms - remain with us in three distinct sub-branches of the tree of life
- the ginkgo, the conifers such as pines, spruces and the like, and the cycad
palms.
About 100 species of cycads exist today, with the most common being the Sago
Palm, Cycas revoluta. Sago palm is native to the Old World tropics from
Madagascar to Japan. Given enough time, this slow growing tree will form a trunk
six feet in length. In China I was shown a sago palm reportedly 1000 years old.
Trunks rarely branch, but if they do, the new shoot emerges from the base.
The evergreen, feather-like leaves are arranged around the stem in a whorl,
producing a symmetrical rosette of leaves three to four feet across. The stiff,
narrow leaflets are dark green on the upper surface with a single midrib down
the center.
All cycads are dioecious, meaning individual plants are either of the male or
female persuasion. In reading the technical descriptions of reproduction in
cycads, I come away feeling as if there is some kind of botanical voyeurism
involved amongst the experts. They are especially intrigued by the fact that the
male sperm cell is the largest in all of biology, almost large enough to see
with the naked eye.
The sago palm, so named from a Polynesian word used to describe a group of
true palms from which an edible starch is produced, is grown outdoors in zones 9
and 10 and survives freezes to about 20 degrees Farenheit. The rest of us are required
to use it as a houseplant if we wish to grow it.
As houseplants sago palms make excellent long-lived specimens. They are very
slow growing, so be prepared to wait for at least a decade to see much of a
trunk develop. Their tolerance of low humidity, low light and varying water
regimes makes them well suited for use as a houseplant. Most plants grow
considerably broader than tall, meaning they can eat up a fair amount of floor
space in the living room. A solution to this space-hog problem is to grow them
as bonsai subjects as do the Japanese.
During the spring and summer months, sago palms benefit from a summer
vacation on the patio. Place them where they get high shade or at least
protection from hot afternoon sun. While little is known about their response to
fertilization, it seems logical to assume that an occasional feeding with a
houseplant fertilizer during this summer will keep them well nourished and as
vigorous as a sago palm can get. Scale insects can attack the plant but are not
usually serious.
By: Gerald Klingaman, retired
Extension Horticulturist
- Ornamentals
Extension News -
February 7, 2003
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