The red succulent rosettes of these Jovibarba heuffelli have grown to fill the narrow space between two rocks.

The small Androsace darvasica which might be easily overrun by larger plants and is instead featured when planted in this narrow crevice .

Mat forming plants such as Azorella trifurcata 'Nana' creep down vertical spaces between rocks, stabilizing the soil on the steep slopes.

The green cushion forming Scleranthus uniflorus was intentionally planted in the crevice while the white flowering Androsace septentrionalis is a volunteer, creating an attractive combination. Seeds naturally lodge in crevices and young plants are nurtured where rocks and soil meet.

This Sandia Mountain Heuchera (Heuchera pulchella) is striking in the crevice between two rocks. When creating a rock garden, rocks are sometimes intentionally split to create a planting crevice.

Hens and Chicks (Sempervivum sp) adapt well to crevice plantings and are sometimes planted alongside more delicate plants to provide shelter and help prevent soil erosion until the smaller plant is fully established.
Greek native Pterocephalus perennis grows happily among the rocks, creeping into the narrow crevice at front.

Photo courtesy of E. Drcar
Fairy Foxglove (Erinus alpinus) has naturalized throughout this Scottish ruin, creating a charming and informal garden.