Published July 17, 2016, in the Wyoming Tribune Eagle Journey Section.
By Barb Gorges
Rock gardens became popular in the 1800s when tourists started visiting the Alps.
Travelers were enthralled by the tough but colorful plants growing on the rocky slopes and brought home alpine plant souvenirs.
It took a few decades to figure out alpine plants need gritty soil, rock and a cool climate to grow successfully. True alpine plants don’t need inches of compost or fertilizer.
Today’s rock gardens aren’t limited to cushions of small plants like the ones we see in our nearby mountains. There are plenty of other kinds of naturally rocky places to emulate.
Master gardener Wendy Douglass takes her cues from the nearby mountains and the prairie surrounding her rural Laramie County home.
The following is a tour of different rock garden styles and options seen through the lens of Douglass’ garden.
In her backyard, Douglass has a conventional rock garden, emulating a group of rocks on a mountain side. On one side of it is a small waterfall that flows via recirculating water pump. On the other side, rocks have been arranged informally, leaving pockets to fill with soil and plants.
But since her yard doesn’t get as much water as the mountains, Douglass has arranged drip irrigation soaker hose throughout.
Another secret is that the base of the natural-looking pile of rocks started out as a pile of concrete blocks. No sense wasting purchased landscape rocks where they can’t be seen.
Normally, when laying a flagstone patio, one tries to get the stones to fit as closely as possible. But not if you are planning to plant it. Tough little plants were blooming in Douglass’s patio when I visited in June. They enjoy the sandy soil in the cracks. When it rains, the water pours off the flagstones and into the cracks, giving the plants more moisture than they would get in an ordinary garden setting.
At the front of Douglass’s house is a dooryard, or more pretentiously, a courtyard, protected on the west side by the garage and on the north side by a low wall. Much of it is planted as a prairie rock garden.
The topsoil Douglass brought in has been eroded by the wind over the last dozen years, leaving a gravelly surface like the real prairie. In fact, among serious rock gardeners, this might begin to qualify as a “scree garden” – emulating those mounds of gravel below the rock faces in the mountains.
Douglas has placed a few rocks among the plants, just as they might show up on the prairie—in fact, many come from elsewhere on the property.
However, this is a garden and so it is a souped-up version of the prairie—more flowers and the grasses tend to be ornamental. Plus, many prairie plants are much taller than the diminutive alpine plants of the traditional rock garden.
And it harbors another secret—an artificial boulder. Douglass and her husband experimented with a technique taught by an Australian company that starts with a pile of rubble covered with a concrete mix and then artfully finished with colored mortar dabbed on by brush.
Similar to fake boulder-building, you can make hypertufa (lighter than concrete) troughs to display a particular collection of small rock garden plants. Multiple internet sites have directions.
Rock gardening took off in Europe and America in the 1920s and, based on the number of rocks installed by landscapers in local front yards, it continues to inspire people today. However, the Chinese and Japanese beat us to it by 1000 years at least.
But those gardens are more about emphasizing unusual rocks, not so much about plants. Douglass has what she calls her Zen garden, a tiny area protected by the house. The plants there can be pruned and shaped by Douglass, rather than the wind and the deer. Small rocks form a swirl on the ground. Sand can be raked in patterns as an act of meditation.
Nearby inspiration for your own garden
There are two fantastic resources close by, public rock gardens, where the plants all have nametags.
The first is the Rock Alpine Garden at the Denver Botanic Gardens. Designed by Panayoti Kelaidis and established in 1980, it is anchored by real boulders and every pocket is stuffed with plants from rocky habitats around the world.
On the left is part of the well-established crevice garden at the Denver Botanic Gardens. On the right is another, newly established for the future steppe garden. Photos by Barb Gorges.
The newest form of rock gardening is here too, crevice gardening, installed by Mike Kintgen, the current curator. You know how freezing and thawing will cause rock to crack along parallel faults? These cracks, or crevices, can be simulated by laying flattish rocks on edge, stacked against each other. Gritty soil placed in the cracks is just perfect for rock plants. Their roots are protected while they spread mats of colorful flowers.
Closer to home is the Gardens on Spring Creek in Fort Collins, Colorado. Installation began there about eight years ago. Arrangements of locally quarried rock display a colorful assortment of heat-tolerant perennials that would do well here in Cheyenne.
A tiny species of chickweed (top) forms a carpet and columbine (above) gets a toehold in a rock pile in the Snowy Range. Photo by Barb Gorges.
My favorite rock gardens are tended by Mother Nature, up on the Snowy Range, especially along the trail that begins at Lewis Lake. The plants aren’t labelled, but at the Forest Service visitor center above Centennial you might find a copy of a book published by the University of Wyoming Extension, “Plants with Altitude.” It identifies high elevation plants that adapt well to gardens and that can often be found at local nurseries.
A word about collecting rocks and plants
Do not take home rocks you find out in the country without permission from the private landowners or permits from the public land managers.
It is illegal to remove anything from a national park—rock, plant or animal, dead or alive. Period. Wyoming’s state parks also do not allow the removal of rock.
Our closest forest, Medicine Bow – Routt National Forest, no longer makes permits available for removing landscape rock for home use.
The Bureau of Land Management’s Rawlins Field Office, which includes southeast Wyoming, allows rock collecting for personal use with stipulations. Only collect along roads and trails, only by hand (no heavy equipment or explosives) and only less than a pickup load. Otherwise, a contract is necessary.
Check local landscapers and rock companies to find out where they obtained their rocks, especially moss rock—the kind that has moss and lichens growing on it. It should have been bought from private landowners or bought via permit from public land. Quarried stone is less likely to have a shady past.
As for collecting plants, cross public lands off your list. Consider private lands only with landowner permission. But usually, the domesticated relatives found at local nurseries transplant better than wild plants. Check the North American Rock Garden Society website for specialty catalogs for rock garden plants.
–Denver Botanic Gardens, www.botanicgardens.org.
–Gardens on Spring Creek, http://www.fcgov.com/gardens.
–North American Rock Garden Society, www.nargs.org: illustrated plant list, beginner instructions, recommended resources.
–“Plants with Altitude” by Fluet, Thompson, Tuthill and Marsicek, available through the University of Wyoming Extension.