Build a Rock Garden This Fall
A rock garden adds visual interest and conserves water in your yard. And cool weather is the perfect time for big landscaping projects. Here’s how to proceed.
As the weather cools off, it’s a great time to handle the manual labor type of jobs around the yard. Rock gardens are natural looking, low maintenance, and colorful additions to the landscape. The Alpine plants used in rockeries are drought tolerant and perfect for saving water, especially with the widespread drought conditions we are experiencing.
A large rock garden can show off groundcovers, shrubs, and trees. A walkway through it would make it more accessible to the homeowner and visitors. Groundcovers work well in smaller versions. No matter the size, rock gardens add year round visual interest to a yard.
The most natural spot for a rockery is a sunny slope. If you are lucky enough to have one, decide if you want to cover the entire thing or just a section. Make an outline with fine sand, and step back. Look at it from various points in the yard and the house. Don’t be in a hurry. Take a day or two to get used to it.
When you have figured out the location, dig down about 1’, removing soil, grasses, and weeds. Fill this back in about 1/3 of the way with fill – gravel, rocks, and chunks of cinder block. Top that with about 3-4” of coarse sand. These layers are necessary for good drainage.
The soil mix that the plants will go in should be made of 1/3 topsoil, 1/3 compost, and 1/3 sand. Paradoxically, this provides water retention and drainage at the same time. It’s a very basic mix you can use for any planting bed or container.
Adding rocks and boulders
Hopefully you can gather rocks and boulders from your land. If not, you can find them from reputable nurseries or suppliers of landscape materials. Do not go onto public land for rocks without a permit. Check with the Bureau of Land Management (BLM), the National Forest Service, and your state and local agencies to obtain one.
Native rock is the best to blend your rock garden in with your property. Gather a variety of sizes and shapes for a natural appearance. Some of these may be of considerable size and weight, so be sure to get help moving them. Have the right tools and equipment available, too.
Scatter the rocks in the garden area so they look as though they were pushed up out of the soil or tumbled down the hill naturally. Starting with the largest, bury them 1/3-1/2 way into the soil to stabilize them. Leave a path for a walkway if you are adding one.
Use up all the boulders, filling in around them with your soil mix. Create planting pockets, angling the rocks towards them so runoff will irrigate the plants. Tamp the soil down lightly, and water it to settle it. Let it settle for a few more days. Add more soil, if need be.
If you can find plants this time of year, they may have a chance to put on some growth before the ground freezes. Trees and shrubs especially prefer fall planting. Nurseries have good sales at the end of the season.
You will probably have to wait until spring to do the bulk of the planting. You will have a bigger selection to choose from, too. In the meantime, a layer of bark mulch will protect the soil.
When designing the planting, consider color, bloom time, size, texture, and shape. Plant for winter interest, too. Branches, flower stalks, and evergreen foliage color will be important when the rest of the yard is brown or covered in snow!
Here is a list of very basic rockery plants.
Experiment and find the unusual. Don’t be afraid to move things around, or remove or add plants after the first season. Balance out the shapes, textures, colors, and bloom times. Give the eye something to look at all year long. Make sure you can see and enjoy it from your indoor and outdoor living spaces. And always garden organically for the soil and the pollinators.