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2003 Highlights &
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Things to Expect & Do
An Agave Stalk
Becomes A Nursery
Pruning My Red Bird
Coping with those
Who Am I?
Going Bananas in the
Small Trees for the
in Citrus Leaves
Landscape Water Use
Results are In
Two Citrus Clinics
A B O U N T I F U L G A R D E N
Going Bananas in the Desert
by Dick Gross,
Banana trees may not be plentiful in Phoenix and
surrounding areas, but if you take the time to look you will occasionally notice
their broad leaves peeking over a back fence or adorning a sheltered enclave in
a front yard. Most of these banana plants will be of unknown or unnamed
varieties, grown more for their appearance than anything else. For the sake of
this discussion, however, it can also be assumed that many of their titled
cousins, the varieties you see in local supermarkets, will flourish here as
Temperatures over 100 degrees and the occasional frost can take their toll, but
with a little luck and a bit of acquired know-how you can raise banana plants
successfully here. You can enjoy the sight of their beautiful, tropical leaves
growing next to your saguaros and palms and, better still, you can treat
yourself to a banana split made with your own homegrown bananas.
The banana is not a tree, but an herb. Julian W. Sauls,
Extension Horticulturist with the Texas A&M University Agricultural Extension
Service, describes it as a tropical, herbaceous plant consisting of an
underground corm and a trunk (pseudostem) comprised of concentric layers of leaf
sheaths. A true stem, with a terminal inflorescence (flower) that bears fruit,
is the last thing to emerge from the center of the pseudostem. The flowers
appear in groups called "hands" along this true stem. They are covered by
purplish bracts, which roll back and shed as the fruit stem develops.
Generally, a bract rolls up and sheds to expose a new hand of flowers almost
PROPAGATION AND GROWTH
A single banana pseudostem will live only 2 to
3 years, or until its fruit is harvested and it is cut down. But the corm from
which it grew can survive for many years, and every one of the dozens of pups it
produces has the potential to develop a stalk of bananas. The corm will
continue to enlarge and store energy to nurture an endless supply of pups.
To harvest the pups for purposes of starting new plants, allow them to reach
about 2 feet in height and then sever them from the mother corm by inserting a
sharp, clean 12-inch to 15-inch narrow shovel to its full depth vertically all
the way around the pup's stem. Worry the base out while inflicting as little
trauma as possible, and wash off all the soil. To conserve moisture in the
corm, lop off all the leaves about 2 inches above the tip of the stem. If a pup
has no roots at all, it probably won't survive. Toss it. Even if there are
roots they won't survive the trauma. Cut them off close to their point of
emergence from the corm, and new roots will grow from dormant eyes at the right
time. Let all wounds scab off in full shade for several days before planting at
the same depth. Keep the soil on the dry side until active new growth appears.
Although you should grow banana plants in full sun, even in the summer, shade
can be an important factor where young transplants are concerned. Normally, new
shoots arising naturally from underground buds in an established corm receive
nourishment from the corm during their first few months of existence. During
this period the other members growing from the same mat provide necessary shade.
However when you sever a young plant from its mother and plant it with its few
roots cut off, you must be prepared to provide shelter and water until it can
grow new roots, adapt to the new environment, and eventually build a colony of
Strong winds tend to shred the leaves of bananas, but the green tatters will
still photosynthesize and manufacture food. You should keep each individual
leaf attached to the plant until at least two-thirds of it has turned brown.
The unattractive dead leaves don't need to be removed after that, but if you
wish to do so for cosmetic purposes you can shred or chop them up and layer the
debris around the base for mulch.
A single banana pseudostem has a short lifespan, producing one stalk of bananas
in about 18 months in ideal soil and climate conditions. In a less-than-perfect
environment, however, you may have to wait 2 years or longer to sink your teeth
into your own homegrown, tree-ripened banana.
Banana plants multiply rapidly. One plant will form a grove in 2 or 3 years,
and will need to be restrained to remain attractive.
FLOWERING AND FRUITING
Bananas frequently bloom in Phoenix, but fruit
is often stunted and limited to 3 or 4 hands with rather bland flavor. Tasty
fruit can be produced here, however.
Poor fruit quality may be a function of genetics, but more likely it is the
result of nutrient deficiency and inadequate water. Quality can also suffer
when the flowering stem is engulfed in a dense banana grove, or grows in close
proximity to other hungry, thirsty vegetation. Fruiting exacts a large energy
toll from the corm, requiring a lot of food and water to sustain it.
Competition for the available nutrients is not helpful. Fertilizers high in
potassium (K) are recommended to enhance quality, and are evidently a part of a
healthy banana's diet.
Strictly speaking, there is there is no such thing as one "banana plant" in
nature. Multiple stems emerge from a corm that continually enlarges and sends
up new shoots. With adequate food and water, you will always have a "herd,"
ranging in size from large to small, popping through the soil. To get the best
and most fruit, especially under less than ideal conditions, you should limit
the population of any group to three stems, staggered in size. You will need
one adult (that will be chopped down to a 2-foot stub after the stalk of bananas
is harvested), one juvenile, and a baby. Remove all other growth.
You can sever suckers at their base as soon as possible after emergence. Scoop
out a hollow and fill the cavity with kerosene to kill the bud that will
otherwise continue to grow and consume energy. After the inflorescence has
emerged, lop off the flower head as soon as the hands fail to set. The
immature, tiny fruits will fall off naturally. Bananas are believed to flower
only after a certain number of leaves have been produced. Guesstimates run to
60 leaves, but the number of months it takes to reach the magic number depends
upon the plant's immediate environment. You can count them if you really wish
to satisfy your curiosity.
After a stalk of bananas has developed, it may be 5 to 7 months before the fruit
is mature and ready to pick. During this period you can protect the stalk from
the direct summer sun by covering it loosely with a reflective lightweight
material such as an old T-shirt. Harvest by cutting the stalk at the yoke when
the ribs on the bananas have practically disappeared and have the appearance of
a supermarket banana. Hang in a dark sheltered spot to ripen, or leave it
protected on the plant. Pick a "hand" at a time, as desired, and let it ripen
on the kitchen counter like any other banana.
The banana needs well-drained, rich organic soil. In warm
weather the plant needs plenty of water, but during the winter months when
morning temperatures drop to about 55 degrees Fahrenheit, growth virtually shuts
down and very little moisture is required. During this time the soil around the
plant should be damp, but irrigate only enough to keep it that way. When
thirsty, banana leaves tend to fold together to conserve moisture. If you study
them, you will soon learn their sign language.
Before planting your banana, you should test the soil's ability to drain. Dig a
post-size hole about 2 feet deep and fill it with water. If it empties within 2
hours, the drainage is ideal. It is very important to note that there is a
danger of overwatering once a banana plant has been put in the ground. If you
irrigate a banana to the extent that the soil becomes saturated, the roots won't
get air and rot will set in. Learn to adjust the irrigation frequency to the
rate at which the water permeates through and out of the root zone with a
flushing action. Wet feet can kill bananas any time of the year, but winter is
a particularly crucial period; water should not be added until the soil is quite
dry during these months. This herb is susceptible to diseases associated with
cool, wet, soggy soil. (Our climate does not appear to harbor numerous other
diseases that tend to plague the banana in the tropics).
Banana feeder roots can reach as far away from the pseudostem as the tips of the
leaves extend outward. A common tendency is to irrigate in a basin tightly
encircling the corm, but under those conditions the plant often languishes from
malnutrition. Roots will not penetrate into dry soil, and a restricted root
system will retard every other feature of the banana plant. So if at all
possible, water deeply and feed to the edges of leaves and just beyond.
It is often said that an old compost pit is the perfect
spot to plant a banana; however, you would still have to fertilize the plant.
Bananas can be fed by foliar application weekly with a balanced, soluble
fertilizer. Apply by drenching the leaves on both sides during a cool part of
the day. It is better to provide frequent light feedings to these herbs only
when actively growing, than to supply sporadic, heavy doses of nitrogen that is
quickly leached away.
During the active growing season, apply 1/4 cup of ammonium sulfate every 2
weeks on non-fruiting plant groups, and 1/4 cup weekly on fruiting plants.
Blend the dry fertilizer into damp soil in a shallow trench at least 18 inches
from the clump, and water it in until a probe can be easily inserted 18 inches
into the ground. Do not fertilize bananas when the morning temperature drops
below 55 degrees. In cold weather, growth has virtually shut down and they
cannot use the additional nutrient.
The average mild Phoenix frost of moderate duration
will never kill the corm and roots, but the tender leaves will freeze readily
unless they can be covered or otherwise protected. The length of the freeze is
often forecast. That information is critical to determine the extent of
protection you put in place. One hour at 32 degrees Fahrenheit may inflict
minor injury; three hours at 33 degrees could kill every tender thing in your
The shock suffered from losing its foliage will delay fruiting and set the
development of a banana back several weeks, thus making the energy you spend
saving it a worthwhile effort. Assume that this winter will bring a frost and
prepare for it in advance. Depending on the frost severity expected, one or all
of the following protective measures can be used if the plants are too tall to
be simply covered with a sheet or frost cloth.
First, remove any heavy mulch from the basin until needed again for preserving
moisture. You can plug in an air fan and direct the air into the leaves. Use
one with the largest volume output you can find. An industrial oscillating fan
on a stand works great. You can protect stems by wrapping them with old jackets
or blankets. You can drape Christmas tree lights on the leaves, or place
floodlight or other heat source underneath. Remember to use electrical devices
In summary, you should grow bananas in full sun in well-drained soil rich in
organic material. Water and feed them well during warm weather, let the plants
rest during the winter, and protect them from the 2 or 3 mild frosts that occur
each year. After that, you can mount a sign in your front yard that reads:
TROPICAL FRUIT GROWN HERE.
Maricopa County Master Gardener Volunteer Information
Last Updated January 23, 2004
Author: Lucy K. Bradley, Extension Agent Urban Horticulture, University of Arizona Cooperative Extension, Maricopa County
© 1997 The University of Arizona, College of Agriculture and Life Sciences, Cooperative Extension in Maricopa County
Comments to Maricopafirstname.lastname@example.org 4341 E. Broadway Road, Phoenix, AZ 85040,
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