Cycads in Southern Nevada - University of Nevada Cooperative

Introduction to Cycads in Southern Nevada /Southwest
Cycad Basics for Southern Nevada/Southwest
Cycads have been on the earth for more than 250 million years. They were here during the
time of the dinosaurs and have evolved very little since then.
Cycads are found throughout the world in locations similar to those areas with palm trees.
Many cycads look like palms, while others look like ferns. There is at least one cycad
native to the United States, which is found in the Southeast, mostly in Florida. Cycads are
not as predominant as palms are throughout the world. As shown on this map, they are
scattered across the world from just above to just below the equator, a distribution similar to
that of palms.
There are approximately 11 genera of cycads, and 185 to 289 species within those genera.
Cycads are found mostly in tropical and subtropical areas, with a few in more temperate
climates. During the time of the dinosaurs, relatives of the present-day cycads were
widespread throughout the world, but now they are located in this relatively small band.
However, they are found in both the Western and Eastern hemispheres. Unfortunately, with
all these species in existence, there are only about 10 that are commonly used in
horticulture. Many more should be. Some cycads are extremely rare and protected by law,
but others are available and should be put into production for ornamental use in landscapes.
The so-called Sago palm or Cycas revoluta is the most commonly used cycad in southern
Nevada and throughout the southwest.
Although cycads resemble palms and ferns, they are not closely related to either. They are
primitive plants that accomplish fertilization with motile sperm. The cycad’s closest relative
is the gingko biloba, a gymnosperm. Like gingko and pine trees, cycads produce cones.
Cycads are also dioecious, meaning they are either male or female. In order to produce
seeds, there must be at least one male and one female cycad.
Basically, cycads have two types of trunks, one that is above ground, which is quite
enlarged, and then one with a subterranean or below-ground trunk. Unlike palms, for which
they are often mistaken, trunks of cycads continue to enlarge with age, similar to the way
trunks on trees expand. Cycads are gymnosperms, meaning that their seeds develop on
cones, which are on the surface of the plant. Cycad trunks can either be branching or single,
depending on the species and whether or not injury has taken place.
Cycads have many niches in the wild and there is even one, this particular Zamia, which is
an epiphyte, a plant that grows on rocks, trees or other plant material. Zamia
pseudoparasitica is an interesting and rare cycad. The name pseudoparasitica means that it
is a false parasite, perhaps at one time thought to be a parasite.
Most cycads reach sexual maturity between two to 30 years in the wild with the average 15
years. The number of years to reach sexual maturity shortens in captivity or in cultivation.
Smaller-growing cycads mature more quickly than larger-growing ones. They may begin
producing seeds in as little as two years. Cycads are very tough plants. If grown in suitable
climates they survive droughts, fire, disease and predators, and sometimes they survive
these problems in very clever ways, as will be discussed later.
This photograph shows the inside of Cycas revoluta or Sago palm. Unlike a palm, which is
a mass of vascular bundles, the inside of a cycad is much different. In the center, is the pith.
Around it are vascular bundles, or the plumbing system, the xylem and phloem. The cortex
and leaf bases form a type of pseudo-bark around the outside of the trunk for protection.
The structure of a cycad can be seen in these fossilized trunks. From the center to the outer
edge are the pith, vascular bundles cortex and leaf bases form the outer pseudo-bark. This
particular cycad fossil is estimated to be over 40 million years old.
The makeup of a cycad, as observed in the previous picture, is shown here inside a living
specimen. Also shown are the emerging new leaves (top right). On the left are the dissected
roots coming out of the stem of the trunk, along with a new offshoot or pup as it is
sometimes referred to. This is one of the ways that cycads are propagated; it is called
vegetative propagation. The so-called pups may be removed and rooted. Many times they
have already rooted down before they are removed.
This is the same Cycas revoluta, dissected showing the entire plant.
This photograph shows the outside of this cycad; the roots, the stem, and the offshoot.
Shown are the old leaf scars, the offshoot or baby plant (pup), new plant, and the mother
plant’s root system.
Cycads are either single-trunked or multi-trunked. Multi-trunked can branch near the top, or
more commonly, at ground level. This may happen at any age. A cycad may be singletrunked for many years and then branch as it gets older.
How long do cycads live? There is a Dioon edule growing at the Fairchild Botanic Gardens
in Miami whose history is known. It is over 263 years old and is quite well-traveled.
Starting in the UK, it has moved to various places in the United States, and finally to its
permanent home in south Florida.
Section II
Cycad roots
Cycads have four types of roots. The primary taproot begins growing at germination. As in
many plants, it helps with establishment and anchoring of the new plant. It also helps pull
the stem into the ground as the plant or seedling matures.
Lateral roots form the largest part of the root system, growing from the primary root. They
sometimes grow into large storage organs as well. Unlike palms, where all the roots are
initiated from a root initiation zone within the trunk near the ground, cycad roots grow more
like those of other dicots.
Cycads also produce what is called a coralloid root. This nitrogen-fixing root has a truly
symbiotic relationship between blue-green algae and the root of the cycad. These are
usually near the surface and they will grow atropic (upwards), meaning towards the surface
rather than down. They are always near the surface and this is why organic mulch or
compost is good to have near and around a cycad plant, especially in dry, hot climates such
as those found in the Southwest.
Cycads also produce adventitious roots; roots that are generated from the trunk or stem of a
plant. Adventitious roots grow from the offshoots or baby plants while they are still attached
to their mother.
Seedling or primary roots are the taproot of the plant. These are seedlings at various stages
of development. They’ve all lost the seed that was attached to them. The smallest seedling,
the one with the blue circle furthest to the right has a single primary taproot coming down
from its newly formed stem or trunk.
The next two to the left are beginning to swell and send out some secondary roots. In the
two seedlings framing the picture, the taproot is beginning to swell within the first year of
life, and already has secondary roots forming. The next picture shows the primary root
coming from the seed itself. New coralloid roots are beginning to grow vertically towards
the surface of the soil, and the new lateral roots are beginning to spread.
This slide shows lateral roots forming on a new seedling and older lateral roots on a mature
plant.
The three primary types of roots are the primary taproot, lateral roots and the coralloid roots
that are found near the soil’s surface. If a plant has been in a container for many years, its
lateral roots will begin to circle as shown here.
The Zamia integrifolia is native to the southeastern United States, and is found mostly on
the Florida peninsula. These cycads form large bulbous food storing stems as they mature.
These particular cycads are large, old plants that were transplanted from the landscape. The
leaves were all removed and then the stem (caudex) was planted into containers in a
nursery. This shows how an older cycad will form these trunks; in this case multiple trunks
near the surface of the ground. This type of growth takes 50 to 100 years. In sandy soil and
receiving only rainfall, a single Zamia integrifolia can grow 5 feet or more across. The time
required to do so in such nutrient-poor soils will take many years.
Here the coralloid roots are shown forming on a seedling. They are growing atropic
(upwards), towards the surface of the soil. They will fix or take nitrogen out of the air for
the benefit of the plant. This is common with plants that have evolved in nitrogen-poor
soils. Growing in this manner makes it possible for them to produce their own nitrogen
fertilizer. The close-up shows how roots grow towards the surface and begin to branch out.
This containerized plant has a large mass of coralloid roots near the surface. Even when
plants are nursery grown in containers where plants have all the fertilizer they need, this
root system forms to produce nitrogen.
This photograph is a close-up of coralloid roots.
These coralloid roots were sliced open with a sharp knife (box cutter or scalpel) for a look
inside. The blue green algae are in a symbiotic relationship with the cycad to produce the
nitrogen.
These adventitious roots are coming off the offshoot, forming before the offshoot has a
chance to root into the ground.
This picture shows the adventitious root with a coralloid root already forming.
Section III
Cycad Leaves
Most palms produce one leaf at a time. Unlike palms, most cycads produce flushes or
groups of leaves at one time. These flushes are produced after either a short or long period
of dormancy, depending on the species and the climate. All leaves in the flush of growth
mature at the same time. These new leaves and cones (for seed production) are produced
during the growing season. The growing season is in connection with temperature and in
most cases rainfall.
Cycads may lose their leaves through drought or fire, or from animals browsing and eating
them. They may go long periods of time without leaves. When they are transplanted, the
leaves are sometimes removed from the mature trunk and may sit for many months to over a
year without a new flush. But as long as its trunk is hard and firm, there is always a
possibility that a new flush of leaves will form once the cycad comes out of dormancy.
As a survival technique, many cycads will produce a brownish, bluish or other nongreen coloration of leaves. Some leaves are covered with pubescence or fuzz-like
substance. They are soft at this point and are susceptible to being eaten by predators. As
they mature, they turn green to photosynthesize. This scheme is a ploy that the cycad uses to
keep from being eaten when its leaves are young and soft.
Most photosynthesis takes place in younger leaves of the cycad. Leaves live an average of
two to four years, but some cycads may have leaves that live as long as 10 years.
Here is a Cycas revoluta. On the left, there is a new flush of leaves emerging from the
center of the stem or trunk. On the right they’re beginning to unfurl and begin the maturing
process.
In this picture, various adaptations to fend off predators are shown. The cycad shown on the
far left is a bluish color. The cycads in the center and bottom right pictures have brownish
fronds that look as though they are dead or have something wrong with them. The top right
picture shows what appears to be a heavy pubescence or whitish coloration on the new
fronds or leaves. All of these adaptations provide protection for the plants.
This Cycas revoluta was produced in a wholesale nursery. On the bottom are sun grown
leaves that are the correct size for this particular plant. Plants of any kind that find
themselves in a shady location will produce elongated leaves to collect more light. There’s
nothing wrong with this cycad, other than the leaves in this flush were produced in a very
shady location. This cultural problem was created by moving this plant from an area in the
wholesale nursery where it was growing in full sun to the shaded retail nursery.
Section IV
Cycad Cones and Reproduction
Because cycads are gymnosperms, they produce seeds differently than palms. They generate
a cone or modified cone. These reproductive organs are made of modified leaves.
Cycads are either male or female. Male cones are smaller and more numerous. Research has
shown that not only do male plants produce more cones, but also more male plants are
found in wild populations. Female cones are larger and can weigh as much as 44 pounds.
Female plants produce fewer cones than males and fewer female plants are found in the
wild.
At one time, pollination was thought to be accomplished by wind but now it is believed that
it is done by insects such as beetles and weevils. In captivity, if beetles or weevils are not
present, pollination must be done by hand.
Cycads are primitive plants that produce a motile sperm. Pollen tubes grow into the vicinity
of the ovaries taking up to two months to do so. Once they grow near the ovaries, sperm is
released near the egg. There must be moisture so that the sperm can swim to fertilize the
egg. This type of pollination is very primitive, and very different from most other plants.
Male cones have a method of attracting and dispersing pollinators. Once the pollinators start
feeding, something triggers the male cones so that they increase in temperature. It drives the
pollinators off with the pollen still attached, and then they fly or crawl to the female cones
to facilitate pollination. Cone temperatures peak in the evenings and early mornings to make
this process possible.
The female sporophylls are shown in this Cycas revoluta. These are new sporophylls. This
modified cone looks like lots of small beige fingers sticking up. The flattened area is where
the seeds will form.
This is an older, mature sporophyll cluster. The large maturing seeds are concealed
underneath the fingers of the sporophyll. Harvest seeds as soon as they become ripe and
before they fall on the ground to prevent poisoning. Cycad seeds can be poisonous to small
children and pets.
The pollen of this Cycas revoluta has dropped onto the leaves. The male cone is upright,
slender and much taller than the flattened modified cone in this particular cycad.
This is a native Florida Zamia. The mature Zamia female cones at the top of the picture are
beginning to shed their seeds. The picture on the upper right shows the seeds shedding from
the cone as well as seedlings from the previous year. The bottom right picture shows the
smaller and older male cones.
This photograph shows a female Zamia integrifolia with its mature cones falling apart and
dropping or shedding their seeds. This is the natural process for cycads.
This slide shows a large female Encephalartos cone on the left and large female dioon
cones on the right. These cones can weigh between 20 and 40 pounds. They take several
years to mature. Seeds need to continue to mature after they are shed so that the embryo is
fully developed before planting.
This is a fully mature female Encephalartos cone that has been fertilized. Over 50 percent
of its seed have shed.
These are large Encephalartos male cones. On the left is a mature male cone that is
beginning to dry up. It is also beginning to lean and fall down. On the right is an upright,
new male Encephalartos cone. This cone will begin producing pollen that will be
transported by insects such as beetles or weevils to female cones.
This is a fasciated or crested male cone growing on Cycas revoluta or Sago palm. This is
very unusual. Scientists are not sure exactly what causes this fasciation or cresting
formation. It happens on various types of plants, usually in the vegetative growth. In this
case the male cone is divided. Instead of one large male cone, many small cones are formed.
Fasciation is becoming more common in many different types of plants, which may indicate
that the environment may be a factor in its development.
Section V
Cycad Culture
The tropics and subtropics create ideal habitats for cycad growth. Some varieties will grow
in temperate landscapes and tolerate cold as well as high temperatures. Although tolerable,
extreme temperatures will damage their leaves. Hot dry soil damages the roots. There are
two main problems people encounter when growing cycads in the desert Southwest,
particularly in southern Nevada. Cold temperatures, which sometimes dip below freezing
and even into the teens, and very high temperatures combined with low humidity create
problems for cycads.
Southern Nevada’s humidity may be as low as 5 percent on some summer days.
Temperatures ranging from 100-110 degrees are not unusual, and in rare cases can reach
120 degrees. Hot dry soils will damage cycad roots, particularly the nitrogen-forming
coralloid roots that grow near the surface. This is why soils need to be kept moist. Organic
mulch will help regulate the temperature, keeping it warmer in the winter and cooler in the
summer. The ideal temperature for growing cycads is 80 degrees during the day and near 60
degrees at night. Southern Nevada only has those conditions in the fall and spring.
Cycads need well-drained soil. Sandy to light loam are the best, neutral to acid is the ideal
pH for them. Some cycads will grow in higher pH soils, but southern Nevada soils have
extremely high pH (8 or higher), and this causes problems. Adding organic material helps
lower the pH and increases drainage and moisture holding capacity.
For the most part, cycads are intolerant of saline or salt in the soil, which again poses a
problem in the desert Southwest, particularly southern Nevada. Some cycads are hardy and
can survive the alkaline soils found in this desert region. Cycads need moist, but not wet
soils. They do not like to stand in water; they will rot.
Organic mulch is beneficial for most plants. Cactus and succulents are the exception. It
modifies temperature and prevents evaporation. Mulching palms and cycads is important, as
it keeps the surface moist and helps protect roots.
Mulch keeps the soil cool in the summer and helps retain a warmer temperature in the
winter. Because the desert is so dry and hot, cycads require more moisture or watering,
especially in the summertime. It’s best to water in the evenings or early mornings when
evaporation takes place more slowly. It is beneficial to wash the leaves off once in a while
to clean the dust and dirt off.
These pictures show ways two cycad enthusiasts came up with to shade their cycads. These
cycads do well in fall, winter and spring when sunlight is less intense and temperatures are
lower. However, when summer comes, plants in full sun can burn. One gardener came up
with a plan to shade with umbrellas. While shading by umbrellas is not a common form of
shading, it does help protect the cycads pictured here. Another gardener built a support
structure and covered it with shade material for protection from the intense summer sun.
The best way to shade is to plant under trees and on the east side of buildings so the cycads
receive afternoon shade.
This cycad was moved from shade into full sun for a display and promptly burned. It is not
unusual for this to happen. When buying cycads, it is best to keep them shaded with shade
cloth when first planted in the landscape or get them used to sunlight gradually. Cycads
should be planted so they receive morning sun and western afternoon shade in the desert
Southwest.
Only brown, damaged or diseased leaves should be pruned. Old cones, if they’re fertile,
should be pruned after the seeds have shed. Non-pollinated cones should also be pruned.
These old cycads in a Florida landscape have many years of fronds still attached, and they
are doing well. But leaving so many old leaves could create a fire hazard or harbor pests.
This is the cabbage look. It is one of the worst ways to prune cycads. The intent is
questionable. The result is a replica of a giant green flower or cabbage. This is not a good
way to prune any plant, especially palms or cycads. Cycads should be left in their natural
state. Prune only dead, diseased or insect-damaged fronds.
Section VI
Cycad Pests
There are few pests that attack cycads in the Southwest. There is one that the Department of
Agriculture works vigilantly to keep out. That is the Asian scale (Aulacaspis yosumatsui)
from Thailand and South China. It is killing Cycas revoluta and Cycas circinalis in Florida
and throughout the rest of the southern United States, including Texas. It has also been
reported in California and Hawaii. It has been intercepted in Nevada by the Department of
Agriculture, and has not yet become established. It is the most serious of potential cycad
pests.
Other potential cycad pests:
Mealy bugs are found mostly in shaded growing areas and in greenhouses. Spider mites can
be a problem in hot, dry areas, especially in the interior-scape. Grasshoppers may eat the
soft new leaves if they’re present. Water spots, which are not a pest, may appear to be.
Check with your local Extension office for updates and recommendations of pest control for
any of the pests mentioned here.
Closeup of Asian scale on cycad leaf.
This is the same leaf shown at a distance. This is typical of Asian scale on cycads, especially
Cycas revoluta. It is so thick, it almost looks like snow on the leaves.
This cycad is totally covered with Asian scale.
This photograph shows an old male cone that has fallen off this cycad and the petiole or
stems of the leaves of the cycad that are covered with Asian scale.
This old Cycas revoluta is dying. The trunk is large, but the top growth has been retarded
due to its infestation of Asian cycad scale. This scale can survive as deep as two feet into the
ground, which makes it tolerant to heat and cold. Asian scale is a tenacious pest.
Mealy bugs look similar to Asian scale, but have more webbing. A close inspection reveals
mealy bugs on this leaf.
Sooty mold can be a problem. Sooty mold is always found where there are, or have been,
sucking insects, such as scale or mealy bugs. Always check to see if there are still live
insects on the plant before spraying with a pesticide.
Cold damage is where part or all of the leaf is damaged and turns brown after a cold period.
Damage depends on the length of the cold spell and how far below freezing the temperature
fell. The more tropical a cycad is, the more protection it needs. More tender cycads can be
grown in containers and moved into a sunny room, garage or greenhouse when the
temperature drops near or below freezing.
Micro climates can make a big difference. Some of these Encephalartos, growing in
southern California, were under a canopy of trees and others were out in the open. The
plants that were out in the open had all or portions of their leaves damaged by the cold
temperatures and wind. The ones under the trees survived with no damage.
This may look like a disease or scale insect, but in reality it is simply water spots - the
mineralization caused by excess overhead watering. Once in a while leaves need to be
washed, but generally speaking, water should be kept off the leaves, especially if the area
has poor water quality. Poor water quality is a common problem in the Southwest.
In southern Nevada, especially at resorts, cycads are an important part of the landscape.
This major resort displays cycads on a waterfall near a Japanese garden. Because the water
was of poor quality it has been chlorinated to keep it clean and fresh, some of the cycads
that were exposed to the overspray had to be replaced with artificial ones after the real ones
died.
When live plants are combined with high quality artificial ones. It’s hard to tell them apart,
and it helps with the overall look of the landscape.
Poor quality artificial cycads do not add anything to the landscape. Extreme desert
temperatures and intense sun take their toll, even on artificial plants.
Section VII
Fertilizing Cycads
Cycads require higher amounts of nitrogen, which is the first number in the three number
series on a fertilizer bag. Nitrogen, phosphorous and potassium (N-P-K) are the three
nutrients that are represented by those three numbers.
Cycads are very slow growing in the wild. Many times they grow in areas that are low in
nutrients, particularly nitrogen. That’s why they’ve adapted to produce their own nitrogen
supply with their coralloid root system.
A good fertilizer for cycads is one with a 3-1-3 ratio plus minor nutrients. Some literature
recommends a 25-7-8 with minor elements as a good fertilizer, but it’s too high in nitrogen.
A slow release 18-6-8 with minors is a better choice. Too much fertilizer can lead to a
build-up of salts in the soil, especially in containerized plants.
The best way to fertilize most plants in a landscape is continuously to add organic material
by way of mulch and compost on the surface of the soil. It eventually works its way down
into the root zone. Mulch and compost not only add nutrients to the soil, but also improves
the quality of the soil.
Fertilizer is more expensive when purchased in small quantities. This 4-ounce container of
Sago Shot Specialty Fertilizer for “Sago Palms” or cycads costs $2. That works out to $400
for a 50-pound bag of fertilizer. Two dollars may seem like a small price for a container of
fertilizer, but a container that size doesn’t go very far. Pesticides tend to be priced in a
similar manner, the smaller the quantity, the more expensive it is per pound of active
ingredient. Buy according to need. Even one plant would require more than 4 ounces, but
certainly not a 50-pound bag. However, a gardener with many palms and cycads could use a
40- to 50-pound bag.
Nutrient deficiencies are a problem in most nondesert plants grown in the Southwest,
especially those that are not readily adapted to low nutrient soils. Nitrogen deficiency in
cycads is one of the three major nutrient deficiency problems in the desert Southwest.
Iron deficiency is a problem in many plants in southern Nevada and the Southwest,
including cycads. An iron-deficient cycad’s new leaves are pale green or yellow with green
veins. Any deficiency that shows up in the old leaves but not the new leaves means that the
nutrient can be easily translocated from old leaves to new ones. That is the case with
nitrogen-deficient plants. However, an iron deficiency shows up in the new leaves and that’s
an indication that it does not easily translocate.
Magnesium deficiency is another one that shows up on the old leaves, and it can translocate
to the newer leaves.
A nitrogen-deficient plant has overall yellowing of the plant, beginning with the oldest
leaves. This is due to lack of fertilizer combined with dry soils at the nitrogen-fixing roots,
which are not growing or have died. This cycad also has tip necrosis on the oldest leaves,
which may be caused by high salts in the soil.
Sometimes problems caused by the environment can look like nutrient deficiency. The
desert climate is very harsh, especially on cycads grown in full sun. The symptoms brought
on by poor culture and the harsh climatic conditions of the desert Southwest are so similar
to those of nutrient deficiency, that a diagnosis may be difficult to make correctly.
Section VIII
Watering Cycads
Watering is fairly simple. Cycads should be kept moist but not wet. They rot easily if kept
too wet. However, do not let the soil and roots dry out. This can be accomplished by
watering correctly and keeping the soil moist in between waterings by mulching with good
organic mulch several inches thick. Mulch must be kept away from the trunk or stem of all
plants, including cycads. Organic mulch improves the quality of the soil by adding more
nutrients. Leaching out salts is important, especially if large amounts of commercial
chemical fertilizers have been used, particularly in containers. Leaching out containers is
accomplished by flushing large quantities of water through the container, making sure it
runs all the way through. This should be done two or three times a month.
These six cycads are growing on the same street in Las Vegas, Nev. Three face west, get no
afternoon shade, have rock mulch and are irrigated only by a drip system. Three face east,
have afternoon shade, lots of water from the turf area, drip irrigation and are surrounded
with a fine rock mulch. The difference in cultural practices makes a noticeable difference in
the growth of the plant materials. Keeping the soil moist and shaded in the afternoon are
positive cultural practices that benefit cycads. Another important recommendation that
would improve the growing condition is to mulch with organic matter.
Section IX
Soil
The requirements for soil are fairly easy. Meeting the parameters is a little more difficult in
the Southwest than in other areas. Soil should be well drained. When planting cycads or any
other plant materials, dig the hole at least twice the width of the root ball, fill it with water
at least once, preferably twice and time how long it takes to drain. If it does not drain within
a few hours, add a drainage chimney in the bottom of the planting hole or find a better place
to plant.
On the whole, the best pH for cycads is 6.5 to 7. 7. Soils in the desert Southwest are highly
alkaline. Organic material will help reduce alkalinity. There are a few cycads that adapt to
the more alkalized soils. But sandy soils with organic material are the best for cycads.
Optimum planting practices would be to dig out a large bed, then fill it with a sandy loam
and a good organic mulch before planting.
Low salt is important also. One can achieve low salt levels by redoing the entire bed or
leaching periodically.
If a cycad is in a container, repot every three to five years, using a good organic potting mix.
Section X
Planting and Transplanting Cycads
Planting Cycads
Planting cycads is like planting other plants. The planting hole should be at least twice as
wide as the root ball, but only as deep. This prevents the plant from settling too deep after
planting. In areas of the Southwest where drainage is known to be poor, fill the hole at least
2 times with water to check the drainage rate and to moisten the planting hole. Backfill with
native soil that has been broken up to facilitate aeration. If using amended soil, redo the
entire planting bed. After planting, always mulch cycads with organic mulch. Keep all
organic mulch away from the trunks of cycads to prevent rot.
Drainage chimneys are used to penetrate a caliche layer that is preventing drainage. They
can be used either on a raised planting area (picture on the left) or in a typical planting hole
(picture on the right).
For large planting areas where the soil in the entire planting area is being amended and there
is a large layer of caliche preventing drainage, several chimneys can be made to facilitate
drainage, as shown in this slide.
Cycads can be transplanted any time of the year, but the best time is just before new growth
begins. In Las Vegas and the rest of the Southwest, this occurs in the spring. In tropical
areas, it’s just before the rainy season. Unlike palms, cycads store large amounts of nutrients
and water in the form of starch in their trunks. They can feed off of the stored nutrients for
many months while new root systems are forming. A cycad trunk may sit for many months,
up to a year in fact, with no leaves while developing a new root system.
Shown in this slide are some commercially-harvested and stored cycads. Some have new
growth. It may be smaller on the first flush than what was cut off originally. On the far left
is some brand new growth, and on the right are trunks that are still waiting to put on new
growth. Be patient. Never throw a cycad away unless the trunk is totally rotted or dried out.
If it’s beginning to rot, cut the rot out and let the cut part dry off. It can be dusted with a
fungicide before replanting. In many cases, a cycad will root again.
Section XI
Cycad Propagation
There are three types of propagation used for cycads. The most common is by seed, similar
to the method used for palms. The second is by division; that is removing offshoots and
cuttings. The third, used infrequently, is tissue culture.
On the average, cones take eight to nine months to mature and shed their seeds. After the
seeds have shed, flesh matures and softens and then the flesh needs to be cleaned off. This
can be facilitated by soaking and rubbing or tumbling of the seeds. A few seeds need to be
cut open to check for the viability of the embryo; that is to see if it’s mature and fully
formed. Some seeds need to be stored in a cool dry place for two to six months for the
embryo to fully mature. If the embryo is not fully mature it will not germinate. So a few
seeds must be sacrificed to determine viability.
When preparing cycad seeds for planting, seeds need to be laid on the surface of the
planting container, flat side down and partially exposed. Do not bury them. Seed containers
need to be 10 to 12 inches deep so that the sinker or taproot has enough room to fully grow.
Seedlings may be in containers from one to two years, sometimes even longer. Never throw
out cycad seeds unless they are totally rotted or dried out. A well-drained soil, good peat and
perlite mix is always recommended. Bottom heat of 80 degrees can accelerate germination.
Check to make sure the embryo is viable before planting seeds, as shown in this photograph.
These Zamia seeds are being cleaned. They have been soaked and their water has been
changed daily for several days. A simple way to clean the seeds, when there are only a few,
is to simply rub them on a hard surface such as a cement slab, as shown here. Many people
have allergic reactions to the flesh on the cycad seeds, so rubber gloves should be used
when cleaning them.
The seeds in these flats are being dried, cured and cleaned as part of the preparation for
planting in a commercial nursery.
This flat of cycad seeds is partially exposed. Because of the partial exposure and the need
for high humidity, a good way to propagate cycad seeds is in plastic containers. The top can
be closed off to help build up extra heat and facilitate quicker germination.
This greenhouse gives public tours. Cycad seeds can cost anywhere from $1 to $10 or more
each depending on their rarity, so these are locked behind a gated area to prevent theft.
Once germination begins, the lids can be taken off. Eventually the seeds are moved to
growing areas in the greenhouse. Young plants are harvested as needed, leaving the older
seeds until they germinate, dry up or decompose. It may take several years for all of the
seeds to germinate.
This picture shows different phases of newly germinated seeds. The top middle shot shows
the seed coat beginning to split off the seeds. The picture on the lower left shows new roots
beginning to come out and a plantlet with a new stem. On the far right a new leaf is forming
from that stem.
This shows a sinker root starting to form. The root can grow 4 to 6 inches long.
Division is another way of producing plants, especially those that aren’t readily producing
seeds. The best time to remove the offshoots is during the growing season. Remove all
shoots with a sharp tool and treat the wound on the mother plant with a fungicide. Trim off
damaged roots if there are any on the offshoot, and if needed, treat that area with a fungicide
also. Always let offshoots dry out before planting.
Use well-drained soil such as sand or a high perlite with peat mix. Leaf cuttings have been
known to root, but more research needs to be done in that area.
The best tools for taking pups, or offshoots, off the mother plant are cactus cutters or
dividers. They’re very sharp, and they have long handles to easily reach inside the mass of
foliage.
This shows pups being cut off of the mother plant.
This shows pups being removed from the mother plant.
Here is the spot left after it’s cut off.
Here is the freshly cut offshoot.
This offshoot has been drying for several weeks. It isn’t necessary for it to dry out that long.
The larger the pup or offshoot, the better chance the cycad has of rooting and surviving.
These offshoots were easily removed from the trunk.
Removal of offshoots from male Cycas revoluta.
Roots are often found on offshoots near the ground. These have been removed. All of the
leaves have been removed. They will be given time to dry before they are planted.
Offshoot growth can be stimulated by removing the top of the trunk, as shown by this Cycas
revoluta. This can also happen when the growing point is damaged or killed in the
landscape.
Never throw cycads away. Remove the rot, let them dry out and re-root. Unless a cycad is
totally rotted or dried out and extremely lightweight, there’s always hope. This Zamia was
rotten on the bottom. The rotted portions were removed, allowed to callous over and the
plant re-rooted. It only took a few months.
Under the proper conditions, many cycads can be saved and the trunks will re-root.
The roots of this Zamia integrifolia, had root rot. The bottom portions or the large
subterranean trunks were rotten. The rotted areas were removed and fungicide was placed
on them. They were allowed to callous and dry over and then were re-rooted. The picture in
the upper left hand corner shows where the rotten area was cut out. These very old and
extremely valuable Zamias were saved and formed new roots.
Section XII
Growing cycads in containers
Cycads grow slower than palms and because of that they make great containerized plants.
They can stay in containers for many years before having to be transplanted.
Cycads lend themselves to a variety of containerized plantings. They have become very
popular as bonsai plants.
This group of bonsai Cycas revolutas is in a southern California nursery. It is a good
example of how cycads can be used as containerized plants.
This is a picture of a fasciated Cycas revoluta. The entire plant, the trunk as well as the
foliage are fasciated.
A clump of Zamia integrifolia native to Florida and the Southeast makes an interesting
pseudo-bonsai container.
This Encephalartos works well in this large container on a patio in south Florida, which
could be used in the Southwest as a patio plant.
In botanical gardens throughout the world, cycads are grown in containers. Here along the
window seats of the great palm house at Kew Gardens are some of the garden’s cycads.
Cycads, like many palms, can be kept in containers until they are planted out.
Double potting is placing a containerized plant into a decorative pot rather than planting
directly into the decorative pot.
Here are two examples of artificial or faux cycads. The one on the left is an old Cycas
revoluta trunk with artificial leaves. Even in death, cycads are useful. The one on the right is
an artificial cycad with a large faux caudex or trunk.
Section XIII
Cycads of Southern Nevada
The most commonly grown cycad in southern Nevada and throughout the desert Southwest
is Cycas revoluta, misnamed the sago palm or king sago. This is a very tough cycad. It is
extremely cold tolerant, will grow in containers, and will sometimes survive in full sun. But
it grows best when planted in partial shade with protection from the afternoon sun.
Under ideal conditions, as those found in areas like Florida and southern California, Cycas
revoluta form very large plants.
These multi-trunked cycads are growing at the Huntington Botanical Garden in southern
California.
These large Cycas revolutas are growing in a sheltered Japanese garden at one of the major
southern Nevada resorts. They are faring well in this protective micro climate.
Cycas taitungensis, or the prince sago is very similar to Cycas revoluta. It is considered
faster growing. Its cold-hardiness is similar to its cousin, Cycas revoluta. However, it is a
rare cycad and difficult to find in southern Nevada nurseries. However, it can be mailordered.
Cycas taitungensis at the University of Florida in Gainesville.
This cycad is in the palm courtyard at the University of Nevada Cooperative Extension
office in Las Vegas. These cycads can be long-lived and are very expensive.
This 100-year-old Cycas revoluta, a beautiful specimen growing in southern California, is
priced at more than $50,000.
A similar cycad that can be grown in containers, but does not perform well outside of
subtropical areas such as southern California and south central and southern Florida, is
Cycas circinalis, the queen sago. This is a tropical cycad reminiscent of the days of the
dinosaurs. It can get quite large as seen by this example in a central Florida public garden.
Dioons are extremely hardy cycads. Dioon edule is one of the most popular and easily
obtained. There are several different varieties of this particular cycad. The picture on the
lower left shows one growing in a more tropical, humid area. The one in the upper right
hand corner was grown in desert conditions.
These perform best when grown in partial shade and mulched with organic matter.
There are various forms of Dioon edule that can be obtained from mail order nurseries, or
ordered through local nurseries.
Many Dioon grow well in containers.
Dioon Mejiae will make it through some southern Nevada winters, but not the coldest ones.
It is a beautiful cycad and in protected areas it might make it through most cold desert
winters with a little protection. Many cycads are good selections for micro climates in the
southwest landscape.
Zamia furfuracea, or cardboard palm, is quite popular. It is a bit expensive in southern
Nevada. A gardener would be taking a chance by planting it in the ground unless it’s placed
in a very sheltered micro climate, such as a courtyard.
However, it does well in containers either as a pseudo-bonsai or in larger containers such as
the one shown in the lower right hand corner of the slide.
In subtropical and tropical areas such as Florida, Zamia reach large sizes.
This Zamia furfuracea in a private garden, planted near the sidewalk and road, shields the
house from view.
Zamia integrifolia, sometimes called Coontie palm, is a native of southern United States,
including Florida. It grows well in the desert Southwest in containers. There are some
variations from other areas of the Caribbean that are taller. In the upper left corner, Zamia
integrifolia are growing in a sand hill cemetery in central Florida. Many of these plants are
50 to 80 years old, and are very slow growing under these conditions. In the right hand
corner, these Zamias are used as a ground cover. These Zamias are only five years old, and
are quickly covering this median.
Zamia integrifolia also perform well in containers. They can be long lived. They have
subterranean as well as surface storage trunks that can be quite extensive. This plant nearly
became extinct during the early settlement of Florida. It was harvested and processed into
starch.
Probably the most famous of all cycads is Encephalartos woodii. Like so many other
cycads, it is endangered. Only one male specimen has ever been found in the wild. All
others were vegetatively propagated from suckers. Indigenous people eventually destroyed
the wild tree. This one at Kew Gardens is one of the few that still exists in collections
throughout the world.
This full and lush Encephalartos woodii is growing at Fairchild Botanic Gardens in Miami
where it is flourishing. Efforts have been made to try to facilitate some of the offspring to
change sex. Scientific literature suggests that cycads have this ability, but so far there have
been no successful attempts to change any of the woodii specimens to female.
Finding More Information
Many palm publications such as the International Palm Society’s Palms, Hardy Palms
International out of the northwest and western Canada, and Chamaerops, out of Europe also
have articles about cycads.
Many books with information about cycads can be found in local bookstores, libraries and
on the internet.
Opportunities from various societies throughout the world are available on the Internet.
Opportunities from various societies throughout the world are available on the Internet.
Opportunities from various societies and botanic gardens throughout the world are available
on the Internet.
Many nurseries have cycads on hand, as well as information.
Credits and References
Credits and References
The future of cycads looks good.
The End
Disclaimers
Disclaimers
Disclaimers
Copyright
Extras