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Death by Pruning?
Horticulture with Extension Agent Jim Moll
BETTER LIVING IN HERNANDO
July 2002 - September 2002
Vol. 11, No. 2
Are we killing our palm trees with over
grooming? The answer may in fact be yes! Palm leaves are important
for two reasons. First the leaves make food for the plant by a
process called photosynthesis. Second they are a nutrient resource
for the newest foliage when the plant does not have adequate
nutrition in the soil. If you remove too much foliage the plant
will slowly starve to death. Often times we see palms that are
given a “hurricane pruning” in order to protect the plant
in the event of a hurricane. The “hurricane cut” may actually
reduce the protection for the palm. The fronds help add protection
to the palm, much like thick walls protect you better than thin
walls or no walls around you at all.
Another common problem is the total removal of
any discolored leaves until only a few green leaves remain. Many
of the palms in the county have some brown tipped fronds and often
the yellowing of the leaves with the midrib of the frond remaining
green. This is a symptom of nutrient deficiencies especially
potassium and/or magnesium. Totally removing these nutrient
deficient leaves speeds up more nutrient deficiencies in the palm.
Why? The answer is the palm is moving potassium and magnesium out
of the lower (and thus oldest) leaves and sending them into the
newest leaves in an effort to “recycle” those vital nutrients.
When you see the lower leaves begin to have brown tips and
yellowing and you remove these leaves you cause even greater
nutritional deficiencies because the plant has not had time to
transport the nutrients to the newer leaves. What about giving the
palm extra fertilizer to help feed it? Fertilizer is not plant
food and can not be a substitute for palm leaves. Fertilizer does
provide plant nutrients (similar to vitamins and minerals for us)
but only the sugars produced by photosynthesis in the leaves is
truly food for the plant. Think of it this way. If you are only
given a vitamin tablet but no food you too would eventually starve
to death. Only the leaves of the plant produce food.
Never remove more than a third of the palm
foliage at any one time. A better way to remember how much foliage
should remain on the palm? Picture a clock. The leaves of the
palms should be from 9:00 to 3:00. Removing any more than that is
simply too much and stress the palm. Stressed palms may come under
attack from palm weevils. Palm weevils eat the heart of the palm.
Once the heart is damaged the injury is fatal to the plant. The
best way to avoid palm weevils is to not over-stress the palm,
especially from over grooming. |
