Common Names: giant dioon, gum palm
Family: Zamiaceae (coontie Family)
Palm Can be Grown in Containers Has evergreen foliage Has Unusual or
The giant dioon palm is a large, attractive and easily grown plant.
Giant dioon has shiny, stiff, light to bright green leaves that grow
in an upright nest shape. Technically the giant dioon is not a palm
but rather a cycad, a living fossil that is one of the earliest cone
bearing plants that trace their origins back to the ancient flora of
the early Mesozoic era. The giant dioon is the largest of the
American cycads and is known to grow up to 50 ft (15.2 m) high in
nature. The typical landscape size for the giant dioon is 5-12 ft
(1.5- tall and 6 ft (1.8 m) across. The trunk of the adult giant
dioon may grow up to 16 in (40.6 cm) in diameter. Giant dioon leaves
are arranged like the vanes of a feather (pinnate), about 5-7 ft
(1.5-2.1 m) in length and extending radially out from the trunk. The
140-240 leaflets on each leaf are small, flat, have small marginal
thorns and are tapered to a sharp point. The giant dioon is
dioecious - it takes two plants to produce viable seeds. The female
cones are 12 in (30.5 cm) or more in length and covered with a dense
wool. Seeds are cream to white colored, oval shaped and
approximately 1.5-2 in (3.8-5.1 cm) long and 1.1-1.3 in (2.8-3.3 cm)
The giant dioon grows in rocky, limestone evergreen forests in
tropical Mexico (Oaxaca, Veracruz, Yucatan) at 300-1500 ft (91-457
m) above sea level.
An attractive and easily grown plant, the fast growing giant dioon
prefers well-drained soil with regular water. Giant dioon is the
most commonly grown Dioon by a considerable margin. Giant dioon will
grow in soils having few nutrients, in limestone-rich soils and on
moderate slopes. Although tolerant of poor soils, the giant dioon?s
growth can be greatly improved through the application of
fertilizers. Most growers find that a fertilizer having an even NPK
balance, and supplemented with trace elements, provides a good start
for cycads. Cycads may then be kept growing well with regular
applications of a balanced slow release formulation such as Osmocote«
Light: The giant dioon may be grown in partial shade, filtered sun
or full sun. Giant dioon prefers partial shade or partial sun to
Moisture: The giant dioon prefers moist to wet soil with good
drainage and regular watering for optimal growth.
Hardiness: USDA Zones 9B - 11. Mature and established plants have
been reported to tolerate temperatures down to 25║F (-3.9║C) for
short time periods, without incurring significant foliage damage.
Propagation: The giant dioon may be propagated by seeds or by
division and replanting of the attractive offsets or "pups" formed
at the base of the plant. The seeds of the giant dioon are reported
to be exceptionally easy to germinate.
Giant dioon is wonderful as a tub plant in a brightly lit spot in
the home, on a porch or deck, or in a conservatory. The giant dioon
provides an exceptionally exotic but nevertheless formal touch in
any garden in warm temperate to tropical climates. A striking
approach is to follow the Asian style, with large paired plants in
containers or feature beds that flank driveways, doorways or gates.
A single large giant dioon makes an excellent feature plant in a
landscape emulating a tropical or desert setting, perhaps
substituting for a true palm where a large crown is desired without
a tall trunk. A giant dioon can also have a spectacular place in a
small garden where space is limited. The giant dioon also makes an
exotic striking understory plant beneath large trees or any
structure that allows at least partial sunlight to pass through.
Use the giant dioon for that very special accent in your landscape.
You too can own your very own living fossil, the name often applied
to cycads because they have changed very little in the last 200
million years. Giant dioon is considered exceptionally easy to grow
- it has not only outlived the dinosaurs but can survive many
adverse forces of nature and oversights of the gardening impaired!
The genus name Dioon comes from the Greek, meaning "two + egg",
because the seeds are borne in pairs. The species name of spinulosum
is derived from the Latin, meaning spiny or thorny. The leaves
(fronds) of the giant dioon are used in decorations and
The leaflets of the giant dioon taper to a sharp point and they also
have small thorns. It is well advised to plant the giant dioon away
from footpaths and walkways. Wear good gloves when handling or
working close to the giant dioon to avoid getting jabbed and