Designing a High Altitude Garden

When gardening at a high elevation, it helps to realize that there are a lot of options. Learn how to choose plants and locations for high altitude gardens.

Rhus aromatica 'Gro-Low'
Item # 82550 		Rhus aromatica 'Gro-Low'
Gro-Low Sumac

each $8.29
3 to 6 $7.99
7 or more $7.79
Chrysanthemum x superbum 'Snow Cap'
Item # 37061 		Chrysanthemum x superbum 'Snow Cap'
Snow Cap Dwarf Shasta Daisy

each $8.29
3 to 6 $7.99
7 or more $7.79
Papaver orientalis
Item # 74860 		Papaver orientalis
Beauty of Livermere Poppy

each $4.99
3 to 6 $4.79
7 or more $4.59
  • Topic: High Altitude Gardening
  • Author: Katherine O'Brien
  • Keywords: zones 3-4, microclimates, high altitude, Garden Design, gardens
  • Date: February 2003

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When creating a landscape at a high elevation, approximately 7500 feet and higher, it’s helpful to realize that there really is an opportunity to grow a large range of plants. The high altitude site varies considerably because of its different microclimates, those being the weather and growing conditions of a limited area. The high altitude site typically has four microclimates: the open exposed area, the sunny but wind sheltered area, the deep shaded area, and the canopied area.

In the mountains of the Southwest, an open area is exposed to high velocity winds from the northwest and southwest. These winds cool the site below thermometer readings. For example, the temperature reads 10 degrees above zero. With a cold wind, the wind chill affecting the exposed vegetation may be 20 degrees below zero. The winds are also very dehydrating to vegetation. It’s this harsh and dry coldness that makes gardening a bit of a challenge in this landscape.

The United States Department of Agriculture has established zones for cold hardiness. The zones are defined by minimum temperatures. Zone 5 (Santa Fe, White Rock, Las Vegas, Placitas, Edgewood) has a minimum temperature of —20 degrees Fahrenheit. Zone 4 locations (Los Alamos, Pecos, Ruidoso, Taos) have a minimum temperature of —30 degrees. Zone 3 (Chama, Questa, Eagle Nest) has a minimum of -40 degrees. The County Extension Service can provide information on local cold hardiness zones; also sales representatives for our High Country Garden catalog have most zone information.

Plants in an open exposed area need to be able to tolerate the intense sun of higher elevations. Plants in these sites situation in Zones 3 and 4 generally are native with small leaves and flowers, which often can escape leaf burn.

Some suggestions are:

  • Trees: Blue Spruce, Ponderosa Pine, Bosnian Pine, Austrian Pine, Scotch Pine, Limber Pine, Swiss Stone Pine, Mugo Pine, Rocky Mountain Juniper, Bristlecone Pine, Gambel Oak, Bur Oak, Foresteria.
  • Shrubs: Mountain Mahogany, Cliffrose, Peashrubs, Sumac, Rock Spirea, Four Wing Saltbush, Artemesias, Potentillas, Barberry, Buffalo Berry and shrub junipers.
  • Perennials: Penstemons, Mexican Hat, Boltonia, Blue Flax, Asters, Gaillardia, Yarrow, Tanacetum, Nepeta, Thyme, Sulfur Buckwheat.
  • Grasses: Grama, Wheatgrass, Sheep Fescue.

A microclimate that is very sunny but wind sheltered has many more plant possibilities. Since the wind chill is no longer a factor in this area, plants that are one zone warmer than the listed zone can be used. Also many plants can be used that would be otherwise desiccated by the wind.

Some suggestions for this area are:

  • Trees: White Fir, White Pine, Limber Pine, American Smoketree, Green Ash, Honey Locust, Mountain Ash, Crabapple, Plum, Linden, Hawthorn, Serviceberry, Amur Maple.
  • Shrubs: Apache Plume, Butterfly Bush, Fernbush, Gooseberry, Honeysuckles, Virginia Creeper, Trumpet Vine, Caryopteris, Perovskia, Lilacs, Forsythia, Cistena Plum, Western Sandcherry, Brooms, Roses, and some ornamental grasses.
  • Perennials: English Lavender, Purple Coneflower, Jupiter’s Beard, Evening Primrose, Coreopsis, May Night Salvia, Solidago, Oriental Poppy, Delphinium, Shasta Daisy.

The north side of a high wall or building is a microclimate that is moister than the sunny areas. Take advantage of the extra water by planting moisture loving species. Care must be taken in selecting species that can tolerate frozen ground for weeks at a time.

Some suggestions are:

  • Trees: White Fir, Gambel Oak, Peachleaf Willow, Aspen, Amur Maple.
  • Shrubs: Dogwood, Spirea, Willow, Mahonia fendleri, Mahonia repens, Serviceberry.
  • Perennials: Columbine, Lungwort, False Nettle, Ornamental Comfry, Daffodils and other shade loving bulbs.

The final microclimate is a grove of trees, where tree canopies overlap as they do in the native forests. This creates a microclimate that protects plants from harsh winds and blazing sun. Soil here has a higher degree of organic matter and a thick mulch of leaves or other porous material. Many shrubs that we associate with the Rocky Mountains live in this microclimate.

Some garden suggestions are:

  • Shrubs: Currant, Chokecherry, Silverberry, Serviceberry, Viburnum, Mahonia, Artcto- staphylos nevadensis, Kinnickinnick, Holly, Wood’s Rose, Gambel Oak, Virginia Creeper.
  • Perennials: Vinca, Saponaria, Veronica, Columbine, Whipple’s Penstemon.

The big limitation in high altitude gardening is usually the lack of soil. Plants require enough soil to establish a root system that will furnish adequate moisture, air, and nutrients. Limit landscapes to areas where adequate soil can be created. Plants will not thrive in bedrock or tufa, our native soft volcanic rock, even when they have been chosen correctly for their microclimate.

Be aware that browsing deer and elk can be a real hazard to mountain gardens. Choose deer-resistant plants or be prepared to fence garden areas, especially when plantings are located away from the house.

The best clue to plants favorable to your area are the natives. Take a look around. Natural plants know best where to grow.