How (and Why) to Grow a Crevice Garden

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A crevice garden is an exceptional way to deal with one of the hardest terrains to grow a garden. But more than that, crevice gardens can create architectural interest and structure, while growing a drought-tolerant garden that can be full of native plants. You can even create a crevice garden in a place that didn’t previously have rocky terrain, if you like the look of them.

With climate change bringing hotter summers, a garden that is drought tolerant while also improving the soil and providing food for pollinators is a win all around. Since these gardens are so low maintenance, they’re perfect for people who want a dramatic, natural garden without a lot of upkeep.  

Crevices provide the perfect growing conditions

If you have a patio, driveway or bricked walkway, you know that plants love to grow in the nooks and crannies, whether you want them to or not. There’s good reason these plants grow in the tiny spaces—the surrounding matter, whether that’s rock, brick, or pavement, provide almost perfect germination conditions. They keep the seeds dark, warm, and moist in the soil, shaded from the sun. The roots are protected, and hard surfaces almost always trap heat, offering the plant what it needs to survive. 

With a crevice garden, you embrace this idea, and either create or adapt rocky spaces. If you have a rock wall, adding plants between the rocks creates a symbiotic relationship: The roots help the wall maintain stability, holding soil and rocks in place, even in storms; the rocks provide drainage, insulation, and minerals that leach into the soil, providing nutrients for the plants. The rocks also act as protection. 

How to start planting in your rock wall

If you have an existing rock wall or outcropping of rocks, you just need to check the conditions to get started on your crevice garden. You'll need enough soil between the rocks to anchor your plants. Use a cup or scoop to pour garden soil into the crevices, only enough so the seedings you place there will touch soil. Once you ensure that your rock wall has enough soil between the rocks, tuck small plants into the crevices. When you pull these plants out of the plastic containers they come in, be sure to free up and spread out the roots, so they’ll begin rooting into the soil once planted. While they’re establishing themselves, ensure the wall gets watered only enough to keep the plants alive. Don’t baby these plants—overwatering will stop the roots from seeking water deep within the soil. Water the plants once after planting, and then watch for signs of plant stress such as wilting before watering again. Remember, water flows down, so if you’re watering a rock wall, don’t overdo it: Water well at the top of the wall and then allow gravity to move the water down to lower plants.

There are different variations on crevice gardens

A new generation of landscapers is using the notion of a rock wall to landscape entire flat yards. Washington State University recently demonstrated this, laying stone slabs parallel to one another, creating gorgeous diagonal lines between which to plant. Plantings are made in small groupings, two or three together.

You don’t need to design your entire yard around the crevice concept: A small outcropping of large rocks creates vertical interest in a large yard. Consider a long, low rock wall to define a change of elevation in your yard, or to shield a sitting area from the wind. 

Once you have rocks or slabs in place, the instructions are the same as for a rock wall. Make sure there's some dirt or soil for the plants to grab onto in the crevices between rocks, or add enough soil to do so. Plant small, drought tolerant plants in the crevices and encourage root growth by watering minimally.

Resources to start your own crevice garden

If you’re interested in starting a crevice garden, consider the book “The Crevice Garden: How to make the perfect home for plants from rocky places,” which is full of suggestions for plants and layouts of 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 zone. This is the perfect time of year, as nurseries are beginning to stock for the spring and summer. This early in the season, you also have time to grow your own seedlings from seed. Seeing what is available will help you envision the colors, shapes and textures your garden can embody. From sedums that will tolerate a Northeast winter to caper berry plants that would thrive in a high desert, your crevice garden has to be suited to the local weather. 

If you’re interested in building a crevice garden from scratch, consider working with a landscape designer. If you want to go it on your own, seek out a local rock yard. These businesses have different rocks, soils, and sands are separated out, and you can walk or drive around and look at each. You’ll purchase the material by the ton, not pound, and can usually opt to pick it up yourself or have it delivered. Someone will walk with you through the yard and show you options. 

You can be as organic or rigid in your design as you'd like, by just placing a few rocks close together or by laying out an entire yard's worth of stone in distinctive planes. The formula remains the same: Identify the spaces between the rocks (the crevices), ensure there's enough soil to plant into, and then place drought-tolerant plants in those spaces.

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