How (and Why) to Grow a Crevice Garden
The crevice garden is an exceptional way to tackle one of the most challenging gardening landscapes. But more than that, crevice gardens can create architectural interest and structure while growing a drought-tolerant garden full of native plants. You can even create a crevice garden in an area that previously didn’t have rocky terrain if you like the look of them.
As climate change brings about hotter summers, a garden that is drought-tolerant while also improving the soil and providing food for pollinators is a win all around. Because these gardens are low maintenance, they are ideal for people who want a dramatic, natural garden that doesn’t require much maintenance.
The crevices provide ideal growing conditions.
If you have a patio, driveway or brick path, you know that plants love to grow in nooks and crannies whether you like it or not. There’s a good reason why these plants grow in tiny spaces: the surrounding material, be it stone, brick or pavement, provides almost ideal conditions for germination. They keep the seeds dark, warm and moist in the soil, shaded from the sun. Roots are protected and hard surfaces almost always retain heat, giving the plant everything it needs to survive.
By creating a crevice garden, you take this idea and either create or adapt rocky spaces. If you have a stone wall, adding plants between the stones creates a symbiotic relationship: the roots help the wall remain stable, holding the soil and stones in place even during a storm; Rocks provide drainage, insulation and minerals that fall into the soil to provide nutrients to plants. Stones also serve as protection.
How to start planting in a stone wall
If you have a rock wall or rock outcrop, you just need to check the conditions to get started on your crevice garden. You will need enough soil between the rocks to anchor the plants. Use a cup or scoop to pour garden soil into the cracks, just enough so that the seeds planted there are in contact with the soil. After making sure there is enough soil between the stones in the stone wall, tuck small plants into the crevices. When you remove these plants from the plastic containers they come in, be sure to loosen and spread the roots so they begin to root into the soil after planting. While they are getting established, make sure to water the wall just enough to keep the plants alive. Don’t over-water these plants – overwatering will prevent the roots from searching for water deep in the soil. Water the plants once after planting, and then watch for signs of plant stress, such as wilting, before watering again. Remember that water flows downward, so if you’re watering a stone wall, don’t overdo it: water the top of the wall well, then let gravity move the water down to the plants below.
There are different options for slot gardens.
A new generation of landscape designers is using the idea of a stone wall to landscape entire flat yards. Washington State University recently demonstrated this by laying stone slabs parallel to each other, creating stunning diagonal lines between which plants can be planted. Plantings are done in small groups, two or three at a time.
You don’t have to design your entire yard like a cleft; a small outcropping of large rocks creates vertical interest in a larger yard. Consider a long, low stone wall to define a change in elevation in the yard or to protect a seating area from wind.
If you have stones or slabs, the instructions are the same as for a stone wall. Make sure there is some dirt or soil in the crevices between the rocks for plants to get caught on, or add enough soil to do so. Plant small, drought-tolerant plants in crevices and encourage root growth with minimal watering.
Resources for Creating Your Own Crevice Garden
If you are interested in creating a crevice garden, consider the book Crevice Garden: How to Make the Perfect Plant Home from Rocky Places, which is full of suggestions for plants and planning crevice gardens.
The best way to start is to visit a local nursery that specializes in natives; explain your project and find out what plants are recommended for your area. This is the perfect time of year as nurseries begin stocking up on supplies for spring and summer. Early in the season also gives you time to start seedlings from seeds. Browsing through what’s available will help you imagine the colors, shapes and textures your garden can embody. From sedums that tolerate northeastern winters to caper plants that thrive in the high desert, your crevice garden should be suited to the local weather.
If you want to build a crevice garden from scratch, consider working with a landscape designer. If you want to do it yourself, find a local rock yard. These plants have different rocks, soils and sands separated and you can walk or drive around and look at each one. You’ll be buying material by the ton rather than the pound, and you can usually pick it up yourself or have it delivered. Someone will walk around the yard with you and show you the options.
You can be as organic or rigid in your design as you like, by simply placing a few stones close together or laying out a full yard of stone in different planes. The formula remains the same: identify spaces between rocks (cracks), make sure there is enough soil for planting, and then place drought-tolerant plants in those spaces.