Tired of the bright, colourful pots full of annuals? Try a crevasse garden, a shallow container filled with strategically placed rocks and alpine plants.
Once established, crevasse gardens take little care and are a source interest all season.
Like other pots, they can be placed in a sunny, but not extremely hot, location.
Make a crevasse garden in a flat container that is approximately five inches (12 cm) deep and at least 12 inches (30 cm) in diameter.
Choose the container wisely. Smaller containers hold less soil and plant material, therefore they dry out quickly. Larger containers have more interest but are heavier to move.
Containers need to have holes on the bottom for good drainage.
Alpine plants that are used in crevasse gardens do better in dry as opposed to wet soil. A mixture of one-third potting soil or peatmoss, one-third compost and one-third sharp sand works well.
Start by filling the pot with soil and contouring the top; adding miniature hills and valleys.
Next, add rocks as they are an essential part of the mountain landscape. Choose flat rocks that are at least six inches (15 cm) in one direction. These rocks are placed into the soil on an angle with enough of the rock buried to support the rock and look natural. Rocks add ornamentation while catching heat or providing shade for the plants. The number of rocks used depends on the size of container and size of rocks. A balance must be achieved between the two.
Dig in the plants next to, under or beside the rocks.
Do not overplant as the plants will self-seed and expand. Three to four plants in a 15-inch (37-cm) container is plenty.
Add a layer of pea gravel to the surface of the pot. It adds grit and keeps the foliage from being in constant contact with wet soil.
Water the container garden daily during the first growing season to ensure that the plants are well established. The container will need less care is subsequent years.
Overwinter crevasse gardens outside. The method used depends on the container as well as what is available.
Plastic and glazed ceramic pots can be covered with an old nylon and dug into the ground. Keeping the rim level with the soil will insure that the plants in the container have protection from cold winter temperatures. The nylon becomes a barrier between the soil and pot, making it easier to clean next spring.
Unglazed ceramic pots should be surrounded by dry peatmoss before being buried. The peatmoss will absorb excess moisture, keeping the clay relatively dry, thus avoiding cracks in the pot when the water in the clay freezes.
An alternative way to winter crevasse gardens is to place them in an area that will be covered with snow all winter.
Alpine plants are available at most garden centres but they are not clearly marked. Different varieties of drabs (whitlow grass), saxifrage and lewisia (bitterroot) are readily available.
Often alpine plants are sold as groundcovers, miniature or dwarf plants. They are also listed in the rock garden section. When making a purchase for a crevasse garden, make sure the plants are slow growing as an aggressive plant will take over the container.
A larger variety of alpines are available through the Devonian Gardens in Devon and Beaver Creek Gardens in Fruitvale, B.C. (www.rockgardenplants.com).
Linda Tomlinson is a horticulturalist who lives near Rocky Mountain House. She who can be reached at www.igardencanada.com or firstname.lastname@example.org.