The living wall at Powell Gardens is magnificent, and the hardy succulents, tough herbs and perennial flowers that thrive here will nestle snugly into the cracks in a stone wall around a patio. All those plants will do fine in a rock garden, even in the most challenging, relentlessly sunny spot.
The plants are full of character, hugging the wall in dense little colonies that seem to bubble up from deep between the stones, elbowing one another in cheerful and colorful crowds.
There are cliff hangers and cave dwellers: Lavender and santolina billow out from the face of the rocks, like puffs of silvery smoke; little button-heads of Sempervivums and Jovibarbas emerge from the shadows of overhangs only a few inches deep. Sedums of every description jostle for space and tumble down the steep face of the wall; tufts of Allium senescens fringe the hard edges of rocks.
These plants grow in a very lean mixture of grit, compost and local soil (one third each), and the gardeners in charge of the living wall jam plants into the cracks using a crowbar, trowels and their fingers. They start with very small plants, massage the roots into the cracks, and caulk around them with a slurry of sphagnum moss mixed with local clay soil to preserve moisture while the plants get their start. These techniques--go easy with that crowbar--work at home too.
Want to see the living wall at Powell Gardens? See my video.