Issue: July 14, 2001

Raining honeydew from willow


I have a willow tree that seems to be "raining" down what feels like moisture in hot weather. Is this common? What is the tree doing? If you look at the tree with the sun behind it, you can see the particles falling. - Pat J., via internet


This is a common occurrence in the summer. The most likely cause is an infestation of aphids in the leaves of the tree. The aphids feed on the liquids in the leaf of the tree. This "sap" is high in sugar and low in protein, so a large quantity of sap must be consumed. Surplus water and sugar (in the form of a syrupy substance called honeydew) is excreted by the aphids. This is the material "raining" down. The windshield of a car parked under the tree will soon be covered with little sticky drops of honeydew. Some people complain of damage to the paint on cars as a result of this.

Aphids may do relatively little damage to an ornamental shade tree, so they are more of a nuisance than a danger. If the tree is small enough, you may be able to manage the infestation by spraying a strong jet of water into the tree. This washes the aphids from the leaves of the tree, stopping them from feeding until some of them find their way back into the tree's leaves (many will die, but many will return). When they are not feeding on the leaves, the raining of honeydew will also cease.

If you think more drastic measures are required, there are insecticides that may be used to effectively control aphids. Check the labels of insecticides at local nurseries for a product available in your area that can be used for management of aphids.

Because you must apply this material to the leaves at the top of the tree as well as lower leaves, it is difficult for a homeowner to spray a large tree. In the case of such a tree, it would be wise to hire a licensed pesticide professional.

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Growing cherry pits


Can I grow a tree from planting cherry and peach pits? How can it be done?


The cherry, like all temperate fruit trees, requires a "chilling" period or winter to prepare the seed for growth. The hard shell of the pit does not need to be removed, but the seed should be placed in moist vermiculite or peatmoss and stored in the refrigerator for six to eight weeks before planting. Do not let the seed dry before beginning this treatment.

Once the seed has been treated by chilling, it may be planted—outside if the weather is already cool, or in a pot in a window or greenhouse. If planted outside, it will experience further chilling and begin growing in the spring. If planted in a pot, it will begin growing in a few weeks.

Plant several seeds because it is possible that only a few will grow. In about seven to ten years you may begin eating cherries from your tree. If you graft a part of your seedling onto a mature tree, you can cut several years from the wait. The fruit from your seedling may be tasty, or it may be bitter. Like apples and peaches, this is a plant that will not produce a seedling exactly like the parent.

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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!