To hear Colorado green thumbs talk, having a successful garden is almost as taxing as a full-time gig. It can take months (years!) of planning, tending, and watering (oh, the watering). Growing prize-winning flowers or heirloom tomatoes may be an admirable goal, but it’s also a ton of work. Is it wrong to want a garden that’s easy?
Crevice gardening, a rock-gardening technique that uses stones and small-growing plants to mimic a natural mountain setting, may be the hassle-free gardening hack you’ve been looking for. If you’ve ever seen weeds growing through a sidewalk crack, you’ve essentially seen a crevice garden in action. When flat stones are closely spaced, they create the same deep, narrow pockets of soil, forcing plant roots to stretch down and between the rocks where moisture collects.
We spoke with two pros, Denver Botanic Gardens’ curator of alpine collections, Mike Kintgen, and David Salman of Denver greenhouse High Country Gardens, to learn the basics of this gardening niche.
- Pick the Right Spot
Crevice gardens should be enjoyed up close and personal. Place yours next to a patio or the porch where you sip your morning tea.
- Gear Up
As with many gardening jobs, gathering the proper equipment is half the work. You’ll need a weed fork, a narrow-bladed trowel, and a watering can with a water-breaker nozzle that mimics rain. Choose rocks (especially flat slabs) of different sizes and shapes.
- Supplement Your Soil
A mix of equal parts topsoil, compost, and squeegee—a blend of coarse sand and gravel—works best. (You can buy squeegee at local Dreamscapes Landscape Center.) For native or xeric plants, use slightly less compost.
- Build a Berm
The berm is the soil mound foundation for your crevice garden. Once it’s the desired size, nestle the stones, fitting the edges together like puzzle pieces in the soil. The point is to make deep, narrow pockets between the rocks—that’s where the plant roots will take hold. Remember: The deeper you mound the soil and set the rocks, the more stable the garden will be. Mulch with small, crushed (not pea) gravel.
- Pick Your Plants
Crevice gardening works best with small vegetation: beardtongue (Penstemon), hens and chicks (Sempervivum), stonecrop (Sedum), rock cress (Aubrieta), dwarf conifers, and ice plants all work well along the Front Range. Water the garden a few times before planting to close any air pockets deep in the soil. Then tuck plants into the narrow crevices you’ve created between the rocks.
- Keep it Up
Once established, crevice gardens are low maintenance, especially if they contain drought-tolerant plants. Pull weeds regularly. Come autumn, pinch or cut off any dead flower stems to maintain a clean look.
More Info! The Rocky Mountain Chapter of the North American Rock Garden Society has an active Denver-based membership. Gardeners, photographers, writers, and artists are welcome at monthly meetings, typically held at Denver Botanic Gardens.