Q: We moved into a new subdivision four years ago and they planted two trees in front of our house as they did this with all of our neighbors. We have now noticed that some of the trees have large splits in their trunks. It seems to be on the south side of the trunks. What causes this condition or how do we stop it for becoming a bigger problem?
S. S. of Maryville
A: This problem develops with young trees during winter when there are a lot of bright sunny days followed by rapid temperature drops rapidly on clear winter nights. The low angle of the winter sun shines directly on the trunk and heats up the trunk, sometimes 60 degrees higher than the air temperature in mid-afternoon.
Snow on the ground can further aggravate this problem by reflecting more sunlight onto the trunk. When the temperature plummets after sundown, rapid freezing of water in the trunk causes the bark to split. Tissue around the split also dries out and dies, weakening the tree. Research at the University of Georgia has shown this injury shows up mainly on young trees from three to seven years of age.
Trees that are less than 3 inches in diameter are too thin to absorb much heat. Trees older than seven have developed thicker bark which prevents splitting.
You can prevent this injury from happening by wrapping the larger lower trunk with tree wrap, which crinkles and has a layer of liquid black asphalt that prevents the bark from becoming heated. You could also place two or three boards on the southwestern side of the trunk.
This may become unsightly in the front yard but would work in areas not that noticeable. You could also paint the trunk with white latex paint to prevent the trunk from heating up. But use a latex paint that does not contain mildew-killing compounds. Painting should be done in late autumn. Many gardeners use the latex paint method on their fruit trees.
Q: Our Alberta peaches developed split pits, became gummy on the inside and developed a bitter taste. Also, one side of the fruit ripens beautifully and the other remains green and is lopsided. What kind of disease do we have and should we spray the trees to prevent this?
L. G. of Belleville
A: Split pits and lopsidedness are physiological disorders usually caused by weather conditions, not diseases. Split pits happen when weather conditions stimulate rapid growth of fruit while the inside of the pit is hardening. For example, this can occur when the weather is warm, the soil is dry and then and you have wet weather. It is common when fruits are large due to poor pollination. Split pits exude bubbles of gum like any injury on a peach tree. The bitterness is thought to be caused from ethylene gas released by the broken pits.
Lopsidedness is common in peaches, plums, and cherries (the pit fruits) because their flowers have two ovules, but one usually withers before bloom. The other ovule goes on to produce a seed. That side of the fruit is often larger, sweeter, more colorful, and sometimes earlier ripening than the other side. This is caused by an uneven concentration of growth hormones. To prevent these disorders, keep the soil evenly moist, especially during the early times of fruit development. Also, do not overfeed with nitrogen fertilizer.
Charles Giedeman is a local contributing writer. Send your gardening questions to Lifestyle Editor Maureen Houston, Belleville News-Democrat, P.O. Box 427, 120 S. Illinois St., Belleville, IL 62222-0427, or email them to firstname.lastname@example.org.
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