Mountain and High-altitude Landscaping

Although high-altitude and mountain landscapes may not be the easiest to work with, those gardeners who perservere can create some of the most beautiful landscapes of any region.

Working with mountain soil

Soil in mountain areas often has to be re-worked for anything to grow in it and plants chosen should be cold-hardy, deer-resistant, and produce before the autumn frost. Some mountain landscapes also require plants that can thrive in the shade and tolorate fallen needles of evergreen trees.

Soil preparation

Soils in mountainous areas vary from light and sandy to heavy clays to adobe that can become stone-hard when dry. Throughout most of the Rocky Mountains, what’s on the ground is more inorganic decomposed granite than soil. Not to mention that fact that mountain soil is often full of stones and pebbles that have to be picked out (preferably to a depth of eight to ten inches, although you'll never get all of them) before planting. Although exactly how you prepare your soil will depend on what you’re starting with, most soils will require added organic material. Don’t rush this -- it's the whole foundation of your garden. Really work organic matter into the soil, espesially if the soil is very poor. Althought it's possible to slowly alter the soil once you’ve planted on it, it’s much easier to get it right the first time. Better to have a good base of soil than limit your choice of plants.

If you’re working with decomposed granite, add sphagnum peat moss to new beds and work it into planted beds during spring cleanup and re-planting. Spread three inches of sphagnum peat moss over an area and work it down into the soil 8-12 inches deep. When you plant, add compost to the bed in a ratio of 1/3 part compost to 2/3 part soil. Most mountain soils have a rather high (alkaline) pH. If you find your soil pH is too high, add sulphur directly to the soil prior to planting the garden and avoid adding akaline materials, such as wood ash, to the soil.

If you’re worknig with clay, add a good, rich compost such as Back to Earth Organic Cotton Boll Compost, made from uneeded parts of organic cotton. Avoid peat moss. Peat moss retains water well, but so does clay, and the combination can result in a drown plant. Moreover, once the peat moss dries, it take hours to become damp again and will, in fact, repel water before it absorbs any.

Another option, rather than adjusting the soil of the whole landscape, is to build raised beds and either mix the local soil with compost as you fill the raised bed or add potting soil. These beds work especially well for clay soils or for soils with poor drainage or heavily compacted soil. Raised beds save space, drain faster, warm up earlier in the spring and save water by keeping it where the plants are. [For more information, see BLI's Raised Garden Beds

Choosing plants

If you’ve prepared the soil well, there are actually quite a number of plants that will thrive in high-altitude landscapes. Perennials, because they die down in autumn and so are not affected by winter elements, are ideal for mountain landscaping. Because of the short growing season, stick with perennials that bloom in early to mid-summer such as brown-eyed susans, painted daisy, yarrow, sunflowers, tiger lilies, oriental poppies, pansies, sweet peas, hollyhock (if your summers are warm), gaillardia, and sweet William. Columbines are one of the most unique-looking mountain natives. Both the Rocky Mountain columbine (Aquilegia coerulea) with blue petals and spurs, white center cups, and yellow centers, and the golden columbine (A. chrysantha) a yellow variety, should do well. Bearded iris and Siberian iris also put on a good, if rather short-lived, show. If you're looking for a climber, the trumpet honeysuckle, which produces sweet-scented, reddish-pink trumpet-shaped flowers for many weeks in the summer, will work well on an arbor or any other climber-support.

Roses
Grafted roses are often not hardy over 6500' and thus will probably not survive the winter. Other roses, such as miniature roses and Rugosa roses, when grown on their own roots, will do well. The Canadian, Parkland, and Explorer series are also good choices. Some varieties that thrive in mountain landscapes are: "Lady Rose", Harison's Yellow (a particularly tough plant), John Cabot, Jeannie Le Joi, Persian yellow, William Baffin, Golden Showers, Hansa, and Theresa Bugnet. These hardy varieties will also be more resistant to mildew. It is important to follow instructions on winterizing your roses by protecting stalks and roots from cold temperatures. The biggest threat to roses is often not the cold, but deer, who seem to consider rose buds a delicacy. Sometimes a simple tomato cage will disuade them, other times not even barbed wire will keep them out.

Shrubs and trees

In a high-altitude landscape, shrubery can serve as insulation and a wind-break. Several mountain-hardy shrubs and trees also bear edible fruit. The serviceberry, with white flowers in the spring, edible berries in summer, and orange-yellow foliage in autumn is a good makes a good year-round pick. The evergreen wild cranberry offers delicate foliage followed by cranberries in the autumn. Another evergreen, the lingonberry, whose fruit is often used in jams and preserves works well as a partrial-shade border.

Other shrubs and trees offer color and shape as their main asset. The bark of the red twig dogwood stands out dramatically against the snows. The Apache plume offers white, rose-like and plume-like pink seed tails. Its white stems stand out nicely against dark foliage. The evergreen curl-leaf mountain mahogany offers not only a graceful shape, it bears colored seed heads in late summer, as well. For autumn color, try the yellow to orange autumn display of the Russian hawthorn, the seeds of which provide food for the birds in winter. In winter, the cinnamon-colored bark of the river birch can add an interesting texture to the garden.

Planting

At high altitudes it's difficult to sow seeds directly into the garden. The ground often doesn't thaw until late spring, and by the time the weather warms up, the intense sun can dry out the soil several inches down in a one day. The simplist alternative is to start seeds in containers indoors in early to mid-spring. When the weather warms up, put the containers outdoors for short periods of time -- starting with a few hours a day and working up to over night. Once the seedling has become used to outdoor weather, it can be planted in the garden. Never transplant a house-kept seedling directly into the garden or the shock could kill it. Also, avoid starting seeds too early as many seedlings become thin and weak if kept in containers too long.

If you do direct sow, try placing boards (either on bricks or directly on the soil) to shade the soil and hold in the moisture for germinating seeds. Check under the boards daily and remove the boards when the seeds germination or the seedlings will become spindly from lack of light.

Greenhouses are another option. If you plan to start a lot of seedlings indoors or want to have place to move your container plants before the autumn frosts come, a greenhouse may be the solution. An inexpensive, simple-to-build lean-to greenhouse will serve basic needs. [For more information, see How to Build a Greenhouse.]

Mountain Landscaping designs

Rock Garden or Apline garden
Most mountainous areas are blessed with a seemingly unlimited supply of rocks. Besides piling them up in some unused corner, there are several ways you can make use of them.

Rock gardens can be created in several ways. The tradtional style consists of several large, half-buried boulders with clumps of plants interspersed between them and bare soil in the remaining area. A rockery -- a "pool" of pebbles edged with a row of medium-sized stones -- will help make use of smaller stones.

Most of the plants that are best suited for rock gardens are Perennials. However, there are some annuals that fit quite nicely with this type of landscape. Some of these include dianthus (Dianthus barbados) shades of pink, white and red. Dianthus is in the carnation family and has the clumping habit that works well in rock gardens. Allysum (Lobularia maritama) fragrant mounding plant. Flowers are very small and white. It is excellent as a border or accent plant for rock gardens. , portulaca (Portulaca grandiflora) moss rose, is a very showy annual that is available in many different colors. A very low-growing plant , and vinca (Catharanthus roseus) Available in white as well as shades of pink and red, the annual type of vinca forms dense clumps with very showy flowers

Alpine meadow
If your landscape includes a large, flat area that you would rather not have to mow, an alpine meadow may be the answer. There are seed mixes of native wild-flowers. Native birds and butterflies will love you for it, so if you enjoy bird-watching, add a pond to attract even more.

Choosing garden accessories

Needless to say, any garden furniture or decor will have to put up with heavy snows and sub-zero temperatures in winter as well as baking sun in summer. These extremes age garden accessories quickly. In this landscape, strong material, like teak and natural stone, is worth the investment. Cheaper material, like pine or concrete, will usually fall apart within a few years. Also, when choosing any roofed structure, be sure the roof will withstand the snowfall in your area.

Garden heating
Summers at high altitudes can be disappointingly short and even at the height of summer evening tend toward chilly. With a little garden heating you can lengthen the warm weather and spend more time enjoying your landscape. Visit BLI's Garden Heating section for more on chimineas, fire baskets, and electric patio heaters.