December Gardening - November 30, 2005
Jeff Schalau, County Director, Associate Agent, Agriculture & Natural Resources
Arizona Cooperative Extension, Yavapai County


Many plants go dormant during the cold winter months. Woody deciduous plants sequester most of the nutrients from leaves before they shed them. The buds remain dormant until conditions are again favorable for growth. The leftover nutrients in the leaves provide organic matter and essential minerals as they slowly decompose on the soil surface. If a deciduous plant is native or drought adapted, then it may not need irrigation during the cold winter months. Other deciduous ornamentals usually benefit from infrequent deep irrigation in the winter months. Irrigation frequency varies with the amount of natural precipitation, but a good rule of thumb is to provide monthly deep irrigation if rain is lacking (or nonexistent).

Evergreen plant growth rates slow down in the winter. Photosynthesis requires water, so demand continues, but is decreased. This is especially true of evergreen ornamentals such as Photinia, Xylosma, pine, juniper, cypress, and other similar plants. Texas ranger (Leucphyllum frutescens), Texas mountain laurel (Sophora secundiflora), and other drought-adapted ornamentals can get by with less supplemental irrigation. When in doubt, simply observe the plant for wilting and irrigate monthly. Newly planted plants should be irrigated more frequently until they become established (one or two years in the ground).

Cool season annuals germinate in the fall, winter, or early spring and finish their life cycle before summer temperatures kill them. In December, these plants appear to grow slowly. This is an illusion because they are producing roots and building energy reserves so that growth can accelerate when the weather warms in spring. Cool season annuals can be flowers, vegetables, or weeds. If they are weeds, then it is much easier to control them in when they are small. If they are flowers or vegetables, a light application of complete fertilizer will increase plant vigor. Organic fertilizers will not be readily available due to cool soil temperatures. So, if you choose to fertilize during winter, use non-organic products.

Some people may be considering purchasing a living Christmas tree that can be planted in the landscape after the holidays. If so, then consider the species and its suitability for your area. Deodar cedar (Cedrus deodara) and Altas cedar (Cedrus atlantica) are really good plant choices for the Verde Valley area. Most often, these are balled and burlapped (grown in the ground, dug, and wrapped in burlap). Deodars are very large when mature. Atlas cedars are smaller and slower growing. Be aware of the mature size of the tree and do not plant it under utility lines or too close to structures or walkways. Many of the small, potted Christmas trees sold during the holidays are not labeled by species. These may or may not be suitable for planting outdoors in our area.

The following suggestions will give the best results if you choose to have a living Christmas tree in the home.
  1. Keep the tree watered prior to planting and especially while it is indoors. Line the tub or container in which you place a living tree with plastic, waterproof paper or foil to keep excess water from dripping through onto your floor or carpeting.


  2. Avoid direct contact of hot Christmas lights with the needles of a living tree, as the heat from some lights will sometimes burn the needles, slightly discoloring them. The newer low watt “twinkle” lights are best because they remain relatively cool.


  3. Keep the living tree in the home for about seven to ten days only. Prolonged exposure to warm household temperatures would force new growth to develop on the tree and this growth would be apt to freeze when the tree was transplanted outdoors after Christmas.


  4. Living trees should not be sprayed with colored Christmas paint or snow.


  5. Once the tree is to be moved outside, allow it to re-acclimate by placing it in a somewhat protected spot such as a garage, porch, or shed for two or three days. Rapid shock from warm to cold will increase stress on the tree.


  6. Fall and winter are good times to plant coniferous trees, so get the tree in the ground as soon as possible following the acclimation period. Be sure to use the improved planting standard when planting. More information on this is available in the May 27, 2003 Backyard Gardener Column available on the web site.
Happy December gardening!

The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.

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Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr. #C
Prescott, AZ 86305
(928) 445-6590
Last Updated: July 16, 2009
Content Questions/Comments: jschalau@ag.arizona.edu
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