Gardening the Desert of Southern New Mexico

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Gazanias growing in a garden in the old riverbed of the Rio Grande.  Photo by Sherry Fletcher.

Desert gardeners face conditions that would wither any other gardener: less than 10 inches of rainfall annually; rocky or caliche (clay) soil with few nutrients; extremes of temperature and weather; oh, and a bit of wind.

However, Southern New Mexican gardeners reap benefits gardeners in the north pine for. Long growing seasons mean active gardening for nine to twelve months of the year. Semi-tropical plants survive in protected areas. An assortment of flowers, grasses, cacti, shrubs, vegetables and trees thrive in this environment, providing exciting design ideas for a desert garden.

Gardens and small farms of Southern New Mexico were historically located in river bottoms and small canyons. They were sheltered from the wind and extreme temperatures. Away from the river bottoms, growing traditional flowers and plants in the Chihuahuan zone is a colossal task. Raised beds, amended soil, shade, wind protection, animal protection, and lots of water are required for plants not adapted to severe desert conditions.

A soil test will save many headaches. Fill a brown bag with a pint of dirt, sampled from around your yard. Take it to your county agent, or call the New Mexico State University Cooperative Extension Service for instructions. The cost is about $12.50. The results will guide you in preparing your site.

Almost always, the soil will need nitrogen, but the results of a soil test will specify the exact amendments your landscape needs. If you have caliche, the cement that stops water 6 to 20 inches below the soil, you must physically break it up, or garden in raised beds..

A drip irrigation system produces the healthiest plants with the least water use because the water penetrates the soil slowly without compacting. Uncompacted soil has room for oxygen, necessary for good plant growth. Drip irrigation encourages plants to develop extensive root systems, flourishing on less water than conventional sprinkling.

Compost and mulch work with the drip system to help plants thrive. Compost is decomposed vegetable matter you can buy or make yourself (over time). Mixed in with the soil, it adds nutrients. In some areas of the Chihuahuan Desert, there is less than 1% organic matter in the soil. Compost acts like a sponge to keep nutrients in the soil and slowly release them to the plants’ roots.

Mulch is placed on the surface of the soil. Use whatever it takes to keep the moisture in and weeds out. Old newspapers laid in garden rows work as mulch, and the newspapers break down after a season, adding to the organic matter in the dirt. Wood chips, dry lawn clippings, old straw and pine needles all work to keep the dirt from drying out. Sawdust is not recommended because it removes nitrogen, an important nutrient.

Microclimates

Some desert gardens use microclimates to benefit the plants. North facing walls provide cool shaded areas. Roofs, sidewalks and streets create areas of high water runoff for collection. Cool air flows into valleys. Be aware of walls and paving which add heat and channel winds. The microclimate includes variables such as sunlight, temperature, exposure, humidity and wind. Big differences can be found in microclimates among neighboring houses.

Groves of small trees or shrubs provide wind control and create “outdoor rooms” for microclimates. Form a mini-oasis by grouping moisture-loving plants where they can absorb collected rainwater. Color influences microclimates, as dark rocks or walls retain heat, and white reflects it.

Cactus

Even cactus gardeners face a challenge in the Chihuahuan desert. Much colder than the famous Sonoran desert of Arizona and Northern Mexico, the higher altitude of the Chihuahuan desert creates problems for non-native cacti.

Mary Lou McCord brought 400 pots of cactus with her when she moved to eastern Sierra County from Tucson three years ago. An avid cactus collector, she found many of her plants didn’t survive the cold winter and strong, drying winds.

Mary Lou remarks, “Cacti love alkali soil, and they can be very adaptable. If conditions are right, cacti don’t require a lot of care.” Two Joshua Trees transplanted from Tucson are doing well in her extreme climate.

For those wanting to grow a cactus garden, Mary Lou advises to dig down three feet to prepare the bed, and take the soil away. Mix gravel and sand to achieve a well-drained medium. She threw in rocks and pot shards for substantial drainage. “Drainage is the key, no matter what,” Mary Lou explains. “If cactus get soggy, they rot. Real sandy soil needs more organic matter, such as peat moss or potting soil.”

She sculpted terraces and small mounds. Recently Mary Lou added some black lava rock, to give tender plants more warmth and heat.

Dave Lamb, co-owner of Buffalo Bill’s Exotic Cactus Ranch, recommends digging a gallon-sized hole in the ground to check for drainage. Fill it with water and check the time it takes to empty. Two to four hours is good drainage. If it takes longer to drain, add gravel, or coarse sand.

Plant a yucca in the hottest, driest, coldest, most unproductive spot in your area. “There are 15 to 17 different yucca varieties,” Dave continues. “The soap tree grows 10-15 feet tall, while the soap weed variety grows lower to the ground. Some yuccas grow 5 to 6 inches a year. Joshua trees and datil yucca are tall types that branch out and have a lot of character.”

Dave’s advice for transplanting a cactus: “Protect yourself.” Mark the north side of the cactus with chalk before digging up, and then orient it in the same direction when planting. Leave the cactus out of the ground for a week, out of direct sun to let cut or torn areas heal over before planting.

Use a rope, rolled up plastic garbage bag or towel to wrap around the cactus. Wrap the towel around the middle of the cactus, and lift the towel, positioning the cactus in its location. It might take two people, if it’s a large plant. “Experiences teaches you not to grab fast, you get too prickled,” Dave explains.

Vegetable gardens

Vegetable growing can be wonderful in this region, if the gardener ameliorates the harsh conditions. Hot weather crops, such as beans, tomatoes, corn and okra start early in February or March, blooming and setting fruit before the high summer heat. In August, it’s time to plant cool weather crops: lettuce, broccoli, spinach and carrots. A variety of food can be grown in a small area by paying attention to the two, possibly more, growing seasons.

Desert Design

A profusion of pink thrives despite heat and wind of the Chihuahuan Desert.  Photo by Sherry Fletcher. blooms.jpg

Diminishing the harsh aspects of the desert is important in any desert garden. Wind, sun and glare rob plants of moisture. Designing a garden from scratch, or improving an existing one, requires planning and work before anything gets planted.

Adjust the contours of the land, adding raised berms and scraping arroyos or basins for water movement or collection. Observe traffic patterns for sidewalks or paths. Design a watering system and add nutrients to the soil. Decide how to mulch.

Orient a shady patio to minimize the heat and glare during the hot seasons. Be aware of the daily movement of the sun from east to west and seasonally from north to south when planning the shade structure. Group shrubs and trees together. Design an arroyo, or dry streambed, lined with gravel and river rocks, with plants alongside. A small fountain or trickle of water attracts birds, adds pleasant sounds and a little humidity. Plant native grasses or wildflowers to suggest a meadow.

Using native plants already adapted to the area increases success in desert gardening. Grasses, shrubs, trees and wildflowers are being used in innovative ways to create beautiful, hardy, water-wise and colorful landscapes.