Willow Cone Gall Midges: More Charm than Harm

Southwest Yard and Garden By Dr. Marisa Thompson

Cone galls on coyote willows just outside Abiquiu on December 1, 2019. Photo credits M. Thompson.

Question: What are these beautiful, tiny cones on willow branches near Abiquiu?
-Malcolm S., Visiting New Mexico for Thanksgiving Holiday

Answer: At first glance, I thought either these aren’t cones or these aren’t willow trees because willows don’t have cones like this, or buds like this either. Full disclosure, the question this week came from my cousin, Malcolm, and I was standing right there next to him. I had noticed the small, multi-trunked trees and assumed they were our native coyote willows (Salix exigua). But I hadn’t noticed that many of these small trees lining the dry streambed were covered in miniature cone structures. Had these “cones” been dangling and covered in leaf debris—like a shaggy grey-brown ornament—I would have thought they’re a form of bagworm. The structures bagworms make look like leafy sleeping bags hanging from bran…

Same Depth, Less Frequent: Irrigating in Winter

Southwest Yard and Garden by Dr. Marisa Thompson
Reprint from December 2017
In most cases, a few inches of snow doesn’t mean we can skip a winter irrigation event entirely. Two cups of snow scooped up from the front yard at the NMSU Agricultural Science Center at Los Lunas on January 3rd melted down to a little over 1/3 cup of water. Photo credit M. Thompson.

Question: I'm wondering what the frequency of winter watering should be and the best time of day or night to have the water come on?
-Rob M., Las Cruces, New Mexico
Answer: It seems #itscomplicated is a hashtag I could use every week. Knowing how much water to apply in your landscape is hard enough in the summertime when demands are high, but it can be even more difficult to know the right amount of water needed when many plants are bare, and it can be easy to forget. Most plants need less water in colder months. This is partly because dormant plants are not actively growing. Lower temperatures also reduce transpiration rates of wat…

Chill Seeker: Some Fruit Trees Are Very Picky about Temperatures During Dormancy

Southwest Yard & Garden
By Dr. Marisa Thompson
Dormant peach trees in February 2019 at the NMSU Agricultural Science Center at Los Lunas. Late frosts after budbreak nipped almost all of the blooms in these trees this year. Photo credit M. Thompson.

Apricot flower bud just starting to open on March 10, 2018 at the NMSU Agricultural Science Center at Los Lunas. Unfortunately, several frosts nipped these blooms in the bud and there was no fruit set that year. Photo credit M. Thompson.
Apple blossoms in April at the NMSU Agricultural Science Center made it through our last frost and many were able to set fruit. Photo credit M. Thompson.

Question: I’m trying to decide which fruit tree varieties will produce well in my yard, and many of them list a specific number of required chill hours. Where do I find out how many chill hours we get in Roswell? -Question submitted via Chaves County Extension Agent Troy Thompson Answer: Many gardeners know that certain seeds need to be cold stratified before…

Girdler Bug Attack: No Treatment Necessary

Southwest Yard and Garden By Dr. Marisa Thompson & Dr. Carol Sutherland

Reprint from November 2017
Mesquite girdler. (photo credit: Dr. Salvador Vitanza,
previously with TexasAgriLife, El Paso, TX)
Our mesquite trees are experiencing what appears to be a girdler bug attack. This is the first time we have experienced this. How harmful are they, and what can be done to rid these pests? -Jack D., Doña Ana County, NM Answer: In order to answer your question, I enlisted the help of NMSU Extension Horticulture Specialist and NM State Entomologist, Dr. Carol Sutherland. Here is her response: Yep. The culprit here is a type of long-horned beetle known as the “mesquite girdler” (Oncideres rhodosticta). Adults are about a half-inch long and are several shades of dark gray, with dots or patches of rusty brown, especially on their forewings. Their most obvious feature is the very long pair of antennae, which is characteristic of most beetles in the Cerambycidae family. The mesquite girdler…

Texas Mountain Laurel: Small Tree, Big Personality

Southwest Yard & Garden By Dr. Marisa Thompson

We are looking for Texas mountain laurel seeds or saplings. We recently removed some invasive salt cedars that were growing on our property and would like to try Texas mountain laurel as a replacement tree. What can you tell us about these trees and where to find them for sale or as seed? -Diane C., Tome, NM Answer: I’m a big fan of the dense-leaved, evergreen, small-statured, clay-tolerant, heat-loving Texas mountain laurel (Dermatophyllum secundiflorum, previously Sophora secundiflora). They are known to be very slow growers. And while I believe them to be worth the wait (slow and steady wins the race), I don’t expect that they’re particularly useful in restoration projects like yours because the salt cedars will likely grow back much quicker. That being said, they are worth a try.

Nurseries in colder regions may not sell them because they are expected to be cold hardy down to 0-10°F (USDA hardiness zone 7), although some reso…

Growing Beautiful Bulbs Can Be a Breeze

Southwest Yard & Garden content and photographs by Marisa Thompson
Question: My friend recently gave me a bag of mixed bulbs to try in my yard. She assured me they’ll be easy to plant and manage, but I’m afraid of killing them before they even have a chance. What are the most important tips for growing bulbs here, and how can I know if I’m doing it right or not? -Suzanne S., Las Cruces Answer: Don’t worry, I’ve simplified the steps for bulb planting in this column and included pro tips from a regionally revered gardener. You’ll know you’re doing it right when the plants sprout and blooms open. Daffodils became my new favorite flower after blooming on my birthday several years in a row in Las Cruces (February 7, if you must know). And if you do it wrong, you’ll likely never even see the bulb sprout, so they’ll be easy to forget.

Because you have a mixed bag of bulbs, we don’t know exactly where to place them, so I recommend splitting them into two groups and planting half in a sunny, wa…

Why Frost Damages Some Plants and Not Others

Southwest Yard & Garden by Dr. Marisa Thompson We harvested and weighed over 1,100 lb of unripe tomatoes from frost-bitten plants last week at the NMSU Agricultural Science Center at Los Lunas. Photo credit M. Thompson.Question: Why did some plants in my garden handle the first freeze just fine, and others died back completely?
-Jane P., Albuquerque

Answer: I was in Las Cruces last week when we got our first two freezes in Los Lunas. Luckily, my poor houseplants on the patio didn’t freeze hard enough—or for long enough—to cause permanent damage. I believe my grandmother would understand and even chuckle if she knew my spider plant that was propagated from hers 20 years ago by my aunt was one of those worried houseplants on my patio. But I shouldn’t have risked it. On those same cold nights at the Agricultural Science Center at Los Lunas, less than three miles away, over 100 plants in our tomato study were practically wiped out. By the time I got to them on Saturday, the droopy leaves …

Comparing Apples to Apples: The Variety Game

Southwest Yard & Garden Question: We need help identifying this apple variety. Our tree was here when we moved in a little over a year ago and we don't know what they are.  -Amanda M.W., Mayhill, NM Answer: More than 7,500 named apple varieties are grown throughout the world today, over 2,500 of which are grown in the U.S. Even if we narrow that down to the 100 or so varieties grown commercially in the U.S., it can be very difficult to determine exactly which variety you are growing in your yard. Even though apples are as American as apple pie and the crabapple is native to North America, true apples are native to central Asia and were introduced by the pilgrims in the Massachusetts Bay Colony. Although I use the terms cultivar and variety pretty much interchangeably, they are distinct in the botanical and horticultural realms. Variety is a formal evolutionary classification (aka taxon) between subspecies and cultivar. Flowering time and harvest time are traits commonly used to narr…