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Playing Favorites: Right Tree, Right Place

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Southwest Yard & Garden by Dr. Marisa Thompson Question: What is your favorite tree species for New Mexico? -Adan O., Albuquerque, NM Answer: Right now, my favorite tree is the alligator juniper outside my office window in Los Lunas, with sparrows flitting around the branches. My favorite tree when I lived in Las Cruces was the peach tree that yielded 40+ lb of deliciousness each year. With temperatures in the nineties here this week, my favorite tree at home is the huge cottonwood that shades most of my back yard—unless I’m in the front yard, where a green ash does all of the shady work and quickly takes the favorite tree superlative in my book. But would I recommend that people plant cottonwoods in their yards? Or green ash? Or alligator juniper? Not necessarily. I don’t recommend cottonwood species in New Mexico landscapes unless the location is so close to the river that the water table is only a few feet deep. And I’m not recommending new plantings of ash trees nowadays because o…

Zotheca tranquila: Cool Name for a Cute Caterpillar

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Southwest Yard & Garden by Dr. Marisa Thompson
Question:
What is a safe, non-chemical way of getting rid of this Zotheca tranquila caterpillar that infests my Mexican elder tree every spring? -Ova L., Sierra County, NM Answer: John White, retired NMSU Extension Agent for Doña Ana County and the current garden curator at the UTEP Centennial Museum and Chihuahuan Desert Gardens in El Paso, TX, calls the Mexican elder (Sambucus mexicana) the “state tree of southern New Mexico.” This semi-evergreen is not as common in northern New Mexico, but it can be found in the Albuquerque area. The Mexican elder is native to the Southwest U.S. and Mexico, but more specifically to the regions’ arroyos, so they prefer more water in the home landscape and are not considered as xeric a plant species as, say, prickly pear or yucca. I reached out to NMSU Extension Entomology Specialist and NMDA State Entomologist, Dr. Carol Sutherland, for information on what she calls a “cute and unique” caterpillar: Althou…

Grape Girdling for Sweetness Is Different than Tree Girdling for Demise

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Southwest Yard & Garden by Dr. Marisa Thompson Question: Why is girdling discouraged in tree care but encouraged in grape growing? -Barry F., Las Cruces, NM Answer: The difference between girdling in grapes versus trees is both subtle and crucially important. We’ve all seen tree rings before at some point, so let’s start there and take a field trip into the wood of the plant. The more rings, the older the tree. The outermost ring, representing the most recent growth, is comprised of layers of tissue, each with a completely different purpose. Imagine for a minute a generic tree with a thin, gummy layer of tissue just underneath the bark that hugs all of the trunk and every branch and root, new and old. This is the cambial tissue layer (or “cambium”), and it is responsible for the trunk and branches getting thicker each year because this is the zone where new cells are generated. Like a fruit rollup, this cambial layer is tender and juicy and can easily be damaged. (New cells are also ma…

Selecting a Table Grape Variety for Your Area of New Mexico

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Southwest Yard & Garden by Dr. Marisa Thompson UPCOMING: Grape Field Day at the NMSU Agricultural Science Center in Los Lunas **early September**  Question: Any suggestions on a good variety of table grapes to plant in my backyard? -Dennis V., Rio Rancho, NM Answer: With over 10,000 varieties of grapes in the world, you’re right to seek help when picking the best one for your garden. I sent your question to our NMSU Extension Viticulture Specialist, Dr. Gill Giese. Here’s what he has to say: Grapes are the most common deciduous fruit crop grown worldwide, and table grapes are popular and common in New Mexico home gardens. However, it is important to select varieties adapted to your local climatic conditions. The most significant climatic obstacle to successful grape production is low or extreme cold temperatures. Winter hardiness, the ability to survive low temperatures during dormancy, differs among major grape groups. Varieties derived from Vitis vinifera (European grapes) that origina…

Getting Your Orchids to Bloom Again and Again in New Mexico

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Southwest Yard & Garden by Dr. Marisa Thompson

CORRECTION: Original post included a diagram without proper citation. The "Optimum Humidity % Diagram" was designed by Mable Orndorff of the New Mexico Orchid Guild and is published here with her permission. Question:
The orchid I got in February has dropped all of its flowers. I clipped the flowering spike just above a lower node, but what else should I be doing to keep it alive and make it bloom again? -Mario M., Albuquerque, NM Answer: Google suggests watering orchids with three ice cubes per week. Guess what, that’s not going to cut it in New Mexico. In fact, that may be a quick way to kill an orchid in these parts. Like many plants, growing an orchid in our dry climate can be a little tricky, once you get the hang of it. People who have gotten theirs to rebloom will tell you it is worth the effort. When I visited Los Alamos County Extension Agent Carlos Valdez this week, I noticed he has several beautiful orchids blooming in …

Gardening in New Mexico is different from the East Coast (REPRINT from April 2009 by Dr. Curtis Smith)

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Southwest Yard & Garden by Dr. Marisa Thompson Written by Dr. Curtis Smith, retired NMSU Extension Horticulture Specialist. Dr. Smith, who authored this Southwest Yard & Garden column for 22+ years, has a new blog! Check it out: Southwest Garden Smith. I've especially enjoyed his recent posts about flowering phenology and soil moisture monitoring.

Question: I have just moved to the Rio Rancho area from the East Coast. What do I need to know about gardening in New Mexico? -J.T.S., Sandoval County, NM Answer: The first thing to learn about New Mexico gardening is that it will be different and difficult, but not impossible. Eastern gardeners are used to adding lime to their garden soil. Do not do that here. Our soil is already very calcareous (contains much calcium). Here you may need to add sulfur. Organic matter is often deficient in our soils. Our soils often contain other mineral salts that can cause problems, and our soils are often deficient in some nutrients. In some cases, t…