Issue: June 21, 2008

Arizona ash trees with flower galls


I have been reading your column and I have a question regarding our Arizona ash trees. We are baffled by the trees this year. The two trees are about 6 years old and they have done quite well for the past years. They grew and looked quite nice. This year however when they budded they never bloomed. The buds look like little pom-poms. Just a small bud sized pom-pom and then about 4 to 6 inches down the branch is another pom-pom. Both of the trees look this way. The larger of the two has somewhat more growth than the smaller one that looks like it should in March. Any help or suggestion you might have would be helpful. We do not want these trees to die. We live in the SW side of Albuquerque.

Rhonda T.


The small pom-poms that you describe are probably the flower buds that were distorted by the ash flower gall mite. NMSU Extension Entomologist, Carol Sutherland says that this is a small mite (strong magnification is needed to see it) that feeds on the male flower buds causing them to develop abnormally. The result is the formation of small ball-like pom-poms. As these flower galls age, they will become woody and persist for more than a year in the tree. They are unsightly, but do not damage the health of the trees. In time they will fall and create a mess on the ground. A potential benefit is that the malformed flowers do not produce pollen, so the mites may reduce hay fever somewhat. However, the unsightly galls on the tree and on the ground are the negative result. These mites are difficult to control and have little effect the health of the tree, so most people do not apply pesticides to deal with the problem. Dr. Sutherland says that when treatments have been tried, the results were unsatisfactory, the mites survived, and the galls remained.

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Summer is not the best time to prune juniper


I have some junipers that have gotten too tall. Is now the right time to prune them, or should I wait until fall?


The best time to prune junipers is late winter or early spring just before growth begins. At that time you can even be cutting away the male cones that produce the pollen that causes hay fever for so many people. A light pruning (smaller branches) around Thanksgiving is a good way to gather greens for holiday decorations.

Now is not the best time to prune juniper, but if you are not cutting large branches and just trimming them back a little, it will probably do little damage. If you are pruning for safety reasons you can do it now. If you are cutting a large part from the top of the plant, it would be better to wait until next winter.

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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:, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at, or at the Desert Blooms Facebook.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!