PLANTS FOR ARID CONDITIONS

by Curtis Smith, Ph.D.  

Q. My husband would like to plant plants and groundcover in our front yard that uses little or no watering. Could you please suggest something and how to care for these plants? Almost everything that we have tried to plant has died. Your help would be greatly appreciated. I'm tired of having an UGLY yard!!

El Paso

A. In your location it is difficult to have a landscape that uses no water, but one requiring little irrigation can be achieved. However, it will be necessary to irrigate for a while until the plants have become established. The length of the establishment time requiring irrigation varies from plant to plant and soil preparation factors but can be a year or more for trees. Some shrubs and perennials can establish more quickly. Use of mulch can also reduce the need for applied water. Another useful technique is the use of “harvested” water; that is, to direct roof run-off water from rains to the root zone of landscape plants. It is important to discover why your earlier plantings have failed. Were they watered enough to allow them to establish themselves in the landscape? Were they appropriate plants? Are there weed control chemicals in the soil which are preventing their establishment? If there are persistent weed control chemicals in the soil, the problem can be solved but it will be difficult. To test for this potential problem, put some of your landscape soil in a flower pot and plant some bean and corn seeds (or some broad-leaf plant and a grass). If there are chemicals in the soil, characteristic symptoms should develop in the plants. Contact your local Cooperative Extension Service office with help if this is the problem. Container-grown plants may be a solution. If the soil does not contain harmful chemicals, then proper plant selection, irrigation for establishment, mulching, and other good management techniques should be adequate to create an attractive landscape.

Plants to consider are numerous, and I will list only a small selection here. Groundcover plants and lower-growing flowering plants to consider include iceplant, Rocky Mountain zinnia, desert marigold, evening primrose, California poppy, Calylophus (sun drops), desert four o’clock, penstemons, and many others.

Shrubs to consider are Buddleia (butterfly bush), Leucophyllum (Texas sage), creosote bush (beautiful if irrigated only slightly),evergreen sumac, Texas mountain laurel, broom dalea (purple sage), hoary rosemary mint (very fragrant foliage), cliff fendlerbush, Ephedra (Mormon tea), Apache plume, Algerita, Artemisia sagebrush species, and many others. There are many shrubs that will grow well in your hot, dry location. Some will do very will with little more than “harvested water” once they are established.

There are also trees to consider. Some become large, others are small: New Mexico Buckeye, western soapberry, fragrant ash, mesquite, palo verde, desert willow, Emory oak (evergreen), Texas madrone (very beautiful bark), junipers, and many others.

Don’t fail to consider ornamental grasses. These are not grown as a lawn but as attractive clumps of grass used like we use shrubs in the landscape. Many of these will require little or no water once established. Of course there are numerous succulent plants to consider. Succulent plants include agave, nolina, yucca, and the cacti. The plants listed above should grow well in El Paso, West Texas, and southern New Mexico. Many of them will also grow in more northern parts of New Mexico and at higher elevation, but not all are adapted to the colder regions.

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Q. The wind broke a branch out of my tree. That branch is now hanging on by only a thin strip of bark. What can I do to re-attach the branch?

Belen, NM

A. When did the branch break? If it was only a few hours ago (not likely by the time I received your message and replied), you can attempt to “graft” it back in place. However, the chances of success, even a few hours after the break, are slim in New Mexico. This is especially true when there is only a thin strip of bark still attached to the branch. Success is also dependent on the size of the broken branch and the species of tree.

The best advice is to remove the branch. Cut it at the point where the strip of bark is still firmly attached to the tree. Once it has dried, this is the only option.

If you repair it quickly after the branch breaks and the branch is not too large, and if the tree is one which has the capacity to graft easily (produce wound closure tissues easily), you may be able to reattach the branch. That is a lot of “ifs”. It is not impossible but can be difficult. You may be able to graft the branch back into place by holding it tightly in place with wood screws or (for a short time) with plastic grafting bands. It is essential that the “cambium layer” of the branch is united with the cambium layer of the trunk. The cambium is a critical layer of dividing cells found just below the bark in trees. The cambium layer of cells produces the new cells that allow “knitting together” of the branch and the tree. These cells replace the xylem and phloem cells which transport water and nutrients in the tree. Once the cambium has dried, there is no chance for successful grafting. If you want to try grafting (the next time this happens) you can find good books on grafting techniques in your local library or bookstore.

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Q. The leaves on my daffodils have turned yellow and died. Should I dig the bulbs now?

A. You don’t have to dig up your daffodils just because the daffodils are dormant. If they produced a lot of blossoms and are not in an inappropriate location, you can just leave them there. They will need a little water through the summer, but very little. In the late winter next year, their leaves will appear again, perhaps with extra leaves produced from newly formed “daughter bulbs.” These will then be followed by the flowers.

In a few years, after the daffodils have multiplied to form a clump of several bulbs, their blooming may decline. Then you may want to dig them and replant them. If nearby trees have grown larger and have begun to shade the daffodils, you may need to dig and move the bulbs, but you don’t have to dig them up just because they are dormant.

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Q. I live in a townhouse and have a very small patio, but I want to grow watermelons. The last time I tried to grow them, they spread all over the patio so that I couldn’t use it. Are there some melons that won’t take over?

Albuquerque, NM

A. There are some melons advertised to have “compact vines.” I don’t know if they will be compact enough to solve your problem. However, if you combine them with the concept of using “vertical garden space” you should be able to grow melons if the location provides enough light. Plant the melons along a strong trellis or wire fence and encourage the melons to climb this supporting structure. This will keep them from sprawling across the patio.

Then the next concern, the weight of the melons, must be addressed. You will need to support the melons on the trellis to keep them from breaking and falling from the vine under their own weight. To do this, form a sling from old t-shirt or old panty hose material. Tie the ends of the sling to the trellis and support the melon in the sling. Be certain that the sling surrounds the melon enough to prevent it from falling out when the wind blows (plan on strong winds). If you choose one of the varieties of smaller “icebox” melons, you should have no problem growing your own tasty melons. This will also work for cantaloupe and small pumpkins. You will also benefit from some additional shade on the patio - just don’t sit under a suspended melon. If the sling fails, that could be a dangerous location.

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Q. How close to a house may I plant a tree? I want to cool the house with the shade, but I don’t want the roots to damage my foundation.

Socorro, NM

A. In our arid climate, the roots are unlikely to grow under a foundation. That is because roots cannot grow where there is no water. Unless you have a plumbing problem, over-irrigate your landscape, or live on a slope that drains water to the base of your house, there should be no water under your house to encourage root growth. In many cases, there is a fairly deep footer (concrete wall underground) that also discourages root growth under the house. Roots may grow up to and along the footer but should not grow under.

A more important consideration is keeping the branches from rubbing against the house and damaging the stucco, siding, or paint and shingles. By planting the plant a distance greater than the expected mature crown radius from the house, you will avoid damage to the house by branches. You will still benefit from shade if the tree is properly positioned.

Many trees are planted so that their branches are trimmed to be higher than the roof and then grow over the roof. Remember, if one of these large branches breaks in a wind storm, it can damage the roof, so distance from the house is the best protection from such damage. Learn how widely the branches spread from the trunk when the tree is mature and plant at least that distance from the house. Yes, you can break this rule-of-thumb, but the hazards increase when you do.

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Send your gardening questions to:
Yard and Garden, ATTN: Dr. Curtis Smith
NMSU Cooperative Extension Service
9301 Indian School Road, NE, Suite 112
Albuquerque, NM 87112

Curtis W. Smith, Ph.D., is a an Extension Horticulture Specialist with New Mexico State University's Cooperative Extension Service. Dr. Smith and Dr. George Dickerson host Southwest Yard & Garden, a weekly program for gardeners in the Southwest. It airs on KRWG in Las Cruces Monday-Friday at 6:30 p.m., Thursdays at 1 p.m. and Saturdays at 11:30 a.m.; on KENW in Portales on Saturdays at 10 a.m.; and on KNME in Albuquerque on Saturdays at noon and Fridays at 2:30 p.m.

Questions or Comments? Email editor@nmjournal.com