Planting in Crevices: Transforming Rock Walls and Boulder Gaps into Living Art

Plant collectors eventually face a hard truth: finite garden space. But hidden opportunities exist in rock walls and narrow boulder gaps. All you need: a small crevice, microclimate knowledge, and ingenuity. The result can be a subtle celebration of form and texture or an exuberant burst of color.

Jeffrey Gordon Smith Landscape Architecture

Shown: Dudleya

Pennsylvania Landscape & Nursery Association

Match plants to your specific climate and microclimates to avoid disappointment.

Succulents for Sunny, Dry Crevices

Warm, dry, sunny walls absorb and radiate heat — perfect for succulents. Their variety of colors, shapes, and textures is unmatched. Check cold hardiness on tags; some common succulents aren't cold-climate suitable.

Shown: Echeveria and Agave attenuata

Schwartz and Associates Landscape Architecture

Sedums are another excellent choice, adapted to wider conditions than Echeveria. Easy in well-drained, sunny spots. Many are drought-tolerant once established — ideal for stone walls. Shorter creeping varieties work best.

Shown: Echeveria and Agave attenuata

Lewis Aquatech

More great succulents

Ground Covers for Sunny, Dry Walls

Mediterranean plants excel in sunny, dry crevices. Consider thyme (Thymus spp., zones 5–9), prostrate rosemary (Rosmarinus officinalis 'Prostratus', zones 7–10), and cheddar pinks (Dianthus gratianopolitanus, zones 3–9). Plant in well-drained soil.

The Carter Rohrer Co.

Ferns for Shaded, Moist Crevices

Shaded walls near water features are perfect for ferns. Choose lower-growing species: Japanese painted fern (Athyrium niponicum var. pictum, zones 3–8), Korean rock fern (Polystichum tsus-simense, zones 7–9), tassel fern (Polystichum polyblepharum, zones 5–8), or Christmas fern (Polystichum acrostichoides, zones 3–9).

Jay Sifford Garden Design

Moss for Humid, Shady Spots

Moss thrives in moist, humid shade. This wall was planted 50+ years ago by David Benner. Purchase from specialty nurseries or transplant from your garden — never collect from wild habitats. Keep consistently moist until established.

Jay Sifford Garden Design

Vines for Cascading Effects

Plant vines in rock crevices or along wall tops to cascade downward. Options: ornamental raspberry (Rubus calycinoides, zones 6–9), creeping Jenny (Lysimachia nummularia 'Aurea', zones 3–9), bougainvillea (Bougainvillea cvs., zones 9–11). Research invasiveness first.

Atelier Nelumbo Garden Design

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Grasses for Flowing Movement

Ornamental grasses bring peaceful cascading lines to walls. Consider Japanese forest grass (Hakonechloa macra cvs., zones 4–9) and sedges (Carex spp. and cvs., zones 5–10).

Jay Sifford Garden Design

More great grasses

Small Shrubs for Structure

Heathers (Calluna spp., zones 4–10) and low-spreading junipers like shore juniper (Juniperus conferta cvs., zones 5–9) suit wall and crevice planting.

Brian Mottershead

More great shrubs