Issue: March 27, 2004

Chinese pistache tree didn't make leaves after freeze

Our Chinese pistache tree will be 4 years old this May. Last spring the tree put out leaves, and then we were hit with a last-minute winter freeze, which in turn killed what foliage the tree had. By mid-March this year, the tree has not shown any indication of having new growth/budding. It has a slit at the base of the trunk near the ground. I'm told that it has died, but I don't want to believe this. Here's hoping you can give me some good news.

I'm afraid the tree is in really bad shape. The freeze last year seems to have done more damage than just the defoliation of the tree.

A freeze can often kill the leaves and buds on twigs while the larger branches and trunk remain undamaged. If the tree didn't produce leaves last year, it is likely that there was more damage than to just the leaves and buds. The cambium (layer of dividing cells under the bark that causes growth in girth) was probably killed. This is the reason that the bark split. The split in the bark is the evidence that the damage was to the cambium.

There is still a very limited possibility that a sprout will develop from just below the ground to produce a new trunk. This will be a slow way to replace the tree, and the new trunk will have wood rotting at its base. This can create a very weak trunk and a potentially dangerous condition. It is probably best to replace the tree. You may choose to plant another Chinese pistache or another species. If you want the red fall color and are not determined to have a Chinese pistache, you might consider a Texas red oak. It is somewhat hardier and provides red color in the fall.

Chinquapin oak is slow to make leaves

I had a rather large Chinquapin oak planted in the late fall. When it was planted, it had no leaves. I am concerned because at the present time it shows no signs of life (no "buds" or new leaves, etc.). Should it have signs at this time, or is it a little early?

The oaks are often slower to produce leaves than some other trees. If other trees have produced leaves, wait a while on the oak. The buds should begin swelling soon. That should give you a sign that growth is about to begin.

It is possible that the tree did not survive the transplanting process. If there was insufficient water in the soil during the winter, the roots may have died and now are unable to sustain growth in the top of the tree. That will become apparent in the next month or so.

The best advice for now is to be patient. Be sure the tree is receiving water at this time. If there is no rain, irrigate at least once a month. As the tree begins to grow (I hope this will happen), begin irrigating twice a month. Applying mulch over the planting site is a good idea to conserve moisture and maintain a consistent temperature in the soil. This also keeps grasses from competing with the developing roots of your tree and keeps lawn mowers and string trimmers away from the tender trunk of the new tree.

If no new leaves have formed by mid-May, you may have a dead tree. Check by scratching the bark on twigs and small branches. There should be a bright green cambium layer just under the bark. Dull green or brown indicates the cambium is dead. If this dead cambium continues to the trunk, the tree is dead. If you find a green cambium layer, there is good cause for hope. You can do this scratch test now if you wish.

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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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