1 - You can prune your fruit trees now and until the buds begin to "show color."

Yard and Garden February 29, 2014

Q.

When is the time to prune roses, irises (& clean up the bed), chrysanthemums, fruit trees before spring in Reserve NM? What is the hardiness zone for Reserve? I get discrepancies when searching the internet.

-Vickie

A.

As far as the garden management questions you asked: You can prune your fruit trees now and until the buds begin to "show color". In some parts of New Mexico, growth is beginning, but in Reserve, you still have some time. Do not prune roses until you are within about a month of your expected last spring freeze. You can probably begin pruning roses in late March. Your experience in gardening becomes valuable in making that determination since you will know when your last freeze occurs at your location. If you prune too early, roses may begin growth and be damaged or killed by a late freeze, but since it will take a few weeks for growth to begin (or resume if you prune off growth that has already begun), you can safely prune 2 to 4 weeks before the last expected frost.

You can begin cleaning you iris and chrysanthemum beds now or in the next few weeks. Irises are best divided in late summer (late August and September).

It is difficult to identify with confidence the hardiness zone in which you are located because of characteristics of your location. The mountains, valleys, and slopes create microclimates that confuse determination of the hardiness zone. However, using your average (expected) minimum winter temperature you can get a pretty good estimate for your zone. The USDA Hardiness zone map lists zones and the range of minimum winter temperatures for each zone. Notice that this is based on the "expected" minimum temperature, not the record low temperature, so it may be wise to consider your zone to be one-half to one zone colder than otherwise. A quick look at the hardiness zone map suggests you are in zone 6, but your specific location may change that. Low areas to which cold air drains will be a colder zone, high elevations will be a colder zone and mid-way in between may be a milder zone. The zone maps are best considered only a rough guide for your area. However, hardiness zone determination may be useful in guiding you to plants that may survive in your areas since catalogs, books, and other resources list plants according to their range of hardiness zones in which they can be expected to survive.

A warning - in New Mexico the mid-winter cold is usually not as important in determining a plants success and survival as the ability of a plant to delay growth until after our common late spring freeze. Plants that break dormancy early, even if they are completely winter hardy, are often injured by spring freezes.

Do not be too concerned with the discrepancies you find on the internet. In the West and in mountainous areas there is great variability in the hardiness zones. Your friends across town or a mile away will have some differences in gardening conditions due the microclimates you will find in your area. In fact, there will be a significant microclimate difference between the north and south side of your own home.

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.

Links:

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

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

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