1 - Iron chlorosis and improper watering can cause home fruit tree problems, but the lack of fruit this year is probably due to late freezes.

Yard and Garden August 10, 2013

Q.

I have three Santa Rosa plum trees. They get fertilizer spikes in the spring and are watered daily. I am getting 2 foot long suckers off the tree. Is this normal and should I be removing them? The growth on the tree has been great but I see no signs of fruit. I also have a Green Gage plum tree that has not grown in size in the last two years. The leaves curl up with brown edges. The tree gets watered daily and receives the same fertilizer tree spikes. Do you have any suggestions? Should I be adding iron to all of my trees and shrubs? My photinias are experiencing the same thing as the Green Gage plum. They do not put out any new grow and the leaves turn yellow then brown. Of my two pear trees, one has great growth but has very droopy leaves that are turning yellow. Is due to an iron deficiency?

A.

Some of the symptoms you described could be iron chlorosis, the symptom of iron deficiency. Iron chlorosis appears as yellowing of leaves between the veins which remain green. In cases of severe iron deficiency the leaves may turn brown, especially around the edge of the leaf.

Yellowing and browning of the edge of the leaves could also indicate salt burn. This could be due to the accumulation of various mineral salts from irrigation water. Excess salts can cause burning and this is called "salt burn". Irrigating daily, especially if insufficient water is supplied and if the water is high in dissolved minerals can cause the burning of leaves you described. Excess salts in the soil and irrigation water are problems in much of New Mexico. The solution is to use plants tolerant of excess mineral salts and proper irrigation that keeps the soil in the root zone consistently moist without overwatering. Overwatering can suffocate roots by filling the voids between soil particles with water and forcing out the oxygen that roots need. In most of New Mexico gardeners can irrigate trees and shrubs two to three times a month with good results. This water should be applied to the region of soil containing roots that actively absorb water. These roots are found from the dripline of a tree or shrub outward from 2 to more than 5 times the height of the plant. Water is not as essential in the zone under the canopy, between the dripline and the trunk. Tree roots can effectively exploit soil water to a depth of two to three feet, so the soil should be consistently moistened to that depth each time you irrigate. Shrubs should be in soil consistently moistened to a depth of two feet.

The production of long water sprouts (you called them "suckers") from the branches is not desirable. If these shoots are in a useful place they may be pruned to shorten them. If they are not in good places they may be removed. Summer pruning is a good time for removal of water sprouts. Such sprouts are often produced to compensate for excess pruning or over fertilization.

The absence of fruit this year is probably due to late freezes that killed the blossoms or the young fruit as they were forming. The drought early this year may also be a contributing factor.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

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