There are few places on earth as well-suited for rock gardens as Utah. No matter where in the state you travel, you are never far from rocks, from the stunning red rock of the south to the massive stone formations of the Wasatch and Uinta Mountains.
Purists cringe at the commonly flippant way most people design these gardens, but true rock gardens appear as they came from nature. Imagine a small section of various sizes and textures of rock materials as they are arranged naturally. The plants fill the cracks and crevices, making the garden a delight to behold.Just because your garden is not as big as Mount Olympus, there is no reason to despair. A garden the size of a ping-pong table could hold dozens of plants and create seasonal interest throughout the year. The generic turf-and-petunia landscape is being challenged by these plants.
The definition of a rock garden is not hard and fast. It is a collection of rocks of various sizes and shapes where a careful selection of low-growing perennials and appropriate annuals, bulbs and shrubs are grown. Although they make look haphazard, they are carefully designed to look like a natural garden might appear.
Installing them is not easy. Spend the time to design the garden on paper or in your mind so you are not moving stones from here to there with no idea of what you want.
A rock garden is a good choice for a slope. The angle of the slope emulates the mountains, and many plants traditionally used in rock gardens come from mountainous or alpine areas. Constructing a rock garden on level ground is more work, but rock gardens do well in areas that are well drained with ample sunlight.
Remove or kill the turf prior to starting the project. Form the slope or berm with rock and other well-drained soil. Next acquire the featured stones from a suitable site. Remember that rocks are not just free for the taking. They belong to private landowners or to the government. Get written permission before removing rocks from any sites. Of course, numerous companies sell rock of all kinds to fit your needs.
Select rocks of the same type but different sizes. Place the largest rocks within the soil base near the bottom of the slope. Arrange smaller ones to give the impression that they have tumbled down. Place all rocks on their broadest side and bury them at least half-way into the finished grade.
Installing the rocks takes a lot of work, but the fun starts when the plants go in the ground. Use the niches between rocks to provide interesting areas for plants.
Many rock gardens feature alpine plants. Again there are no hard and fast definitions. Rock garden plants are generally dwarf types, growing under a foot in height. They usually form tight carpets, clusters or rosettes of foliage that are covered with seasonal flowers Most rock garden plants are perennial and grow larger each year.
The big question about rock gardens is why the rocks? They have a definite and important purpose. They shelter delicate plants from too much sun and keep the roots cool.
Choose a your garden site where it can be enjoyed. Sun or partial shade allow the widest variety of plants. Separate them from the regular perennial and annual borders with their large plants and overpowering or invasive tree or shrub roots.
Well-drained soil is essential. Poorly drained soil is fatal to many of these plants. Never use heavy clay or silt soil. Add organic matter as needed to create a favorable growing environment. Soil depths of 18 inches or more are best for these plants because they are native to harsh environments and sink deep root systems.
Native rock harmonizes with gardens better than exotic rocks. Choose all sizes and arrange them in masses or groups. Do not make walls or fortresses or scatter them in rows around the garden.
Here's list of plants for Utah rock gardens
Aquilegia flabellata "Nana"
Crocus, wild species
Dianthus, perennial types
Dwarf conifers and dwarf shrubs
Erigeron, dwarf species
Iris pumila & cristate
Phlox, creeping kinds
Potentilla aurea "Nana'
Primula polyanthus & species
Saxifraga (many kinds)
Sedum (many kinds)
Sempervivum (many kinds)
Silene alpestris, schafta
Veronica, dwarf species
More information on rock gardening is available through:
American Rock Garden Society
15 Fairmead Road
Darien, CT 06820
Wasatch Rock Garden Society
1564 Wasatch Drive
Salt Lake City, UT 84108