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Index : Trees
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- 15. Palms Need Special Care - Top
- If your palms are looking a little peaked, it could be their not getting the care they need.
Although some varieties of palms, such as the "true" date palm (Phoenix dactylifera), and
Mexican fan palm (Washingtonia robusta) come from arid regions of the world, they need some
special care to flourish here in the Sonoran desert. The reward is a luxuriant tropical appearance
that provides a pleasing compliment to equally exotic native species; like the saguaro and octopus
agave.
Deep water on a regular basis. Even palms adapted to arid regions, such as date palms and
Mexican fan palms benefit from watering every two to three weeks during the spring and
summer. Other palm species originating in moister regions of the world, such as queen palm
(Syagrus romanzoffiana) and pindo palm (Butia capitata) need watering every one to two weeks.
Water deeply, so that the soil is wetted to a depth of two feet. Palm roots will extend out as far
as irrigation is provided from the trunk. Water out from the trunk a minimum of four feet. A
watering basin can be made by forming a circling ridge of soil several inches high.
Fertilize with "palm special" fertilizer. Palms have exacting needs when it comes to nutrients.
Scientific research has determined the best ratios of macro and micro nutrients. These are now
available in so-called "palm special" fertilizers. Not all such fertilizers are the real thing. Look on
the label to make sure the nutrients are in the following proportions: nitrogen (10% to 20%),
phosphorous (5% to 10%), potassium (10% to 20%), magnesium (2% to 5%), and (.5%) of
manganese and iron. It should also contain sulfur and trace amounts of zinc and copper.
Nitrogen and potassium should be in equal percentages and in a slow release form.
Dry, granular fertilizer should be broadcast or banded under the canopy of the palm, or equally
distributed around the drip emitters. Never place fertilizer against the trunk. One application in
March and another in June or early July should be adequate. For palms under eight feet tall, 2-5
lbs of fertilizer per feeding should be adequate. Newly planted palms can receive even less (½ to
2 lbs depending on the size). Large, mature palms should receive 5 to 8 lbs each application.
If palms are suffering from nutrient deficiencies, then supplemental amounts of the deficient
nutrients will be required. Magnesium deficiencies are common on date palms (Phoenix species).
Older leaves turn yellow first, progresssing up to younger leaves. Leaflet tips yellow while the
bases remain green. Correction of this deficiency requires the addition of magnesium sulfate to
the soil.
Queen palms are often deficient in manganese, not to be confused with magnesium. Manganese
deficiency on Queen palm causes the new leaves to become yellow or brown and frizzled, which
gives this disorder it's common name: "frizzle top". New growth is crinkled and distorted.
Correction of this deficiency requires the addition of manganese sulfate to the soil, and as a spray
on the new growth. Manganese deficiency is also common on sago palm or king sago (Cycas
revoluta). Although palm-like in appearance, sago palm actually belongs to a family of prehistoric
plants called Cycads.
Pruning should never be excessive. Hurricane pruning is a common practice along the Atlantic
and Gulf Coasts. All but the very top fronds are removed just prior to Hurricane season. Hear in
Tucson we have no hurricanes, and yet the practice of hurricane pruning, or "rooster-tailing" is
alive and well. This excessive pruning of palms is not recommended. Only yellowing or brown
fronds should be removed from palms. Green fronds manufacture the food reserves to provide
for new top and root growth. Removing these fronds gradually weakens the palm, slowing it's
growth and making it more susceptible to insect and disease problems.
Sometimes commercial pruning practices dictate the removal of some green fronds, but never
should this be excessive. Superimposing an imaginary clock face over the leaf canopy, pruning
should never remove those leaves between the 10 o'clock and 2 o'clock positions.
If your pruning your own palms, allow the yellowing leaves to turn brown before removing them.
Palms draw the nutrients for the old, yellowing leaves and transfer them to the newer growth.
This reduces the chances your palms will become nutrient deficient.
For more information on palms and other gardening topics contact the Pima County Cooperative
Extension. Master Gardeners are available from 9:00 a.m. to 4:00 p.m., Monday thru Friday to
answer your gardening questions. Our Plant Clinic phone number has been changed, as of July 1,
our new number will be 626-5161.
- Updated: June 30, 1996
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