Selecting plants that will live and thrive in sunny, dry, rocky areas or rock gardens can be challenging. The plants in this picture were successful in sunny, 12” strips between steps made of railroad ties. The soil is rocky and unirrigated.
Top Step – Sedum ‘Angelina’ (on the left) is showing its bright chartreuse summer color. In winter it will take on shades of orange to red. Sedum acre (on the right) is displaying its early summer yellow blooms, which contrast with the purple-blue spikes of the Nepeta ‘Walker’s Low’ to the right of the steps. The ‘Walker’s Low’ will eventually get 2’-3’ tall as the summer progresses, but the Sedum will stay low and not interfere with foot traffic.
2nd Step – Sedum acre is joined by various Sempervivum, Orostachys iwarenge, a creeping thyme and Violas that self-sowed. To the right, Calylophus ‘Prairie Lode’, a Texas native, displays yellow buttercup blooms on wiry stems dressed with narrow green leaves. It starts its bloom in late spring and will continue into late fall. ‘Prairie Lode’ is a real showstopper and one of our favorites for hot, dry areas. It stays close to the ground at only 6”-8” tall and its spread can easily reach 18”. However, the main plant usually remains about 6” wide and the semi-woody stems do not root in.
3rd Step – Wooly Thyme flows over the left side of the step while Elfin Thyme, growing 1” tall, hugs its neighbor, the magenta flowered Delosperma ‘Tiffindell Magenta’. To the right Thyme ‘Coccineus’ spreads over the edge and blends into surrounding groundcovers.
4th Step – Thyme ‘Pink Chintz’ (center) reaches only 3”-4” tall, which allows the Sedum ‘Dragon’s Blood’ to peek through. Delosperma ‘Kelaidis’ (not available at this time), on the left, is pretty in pink. More Elfin Thyme shares space on the right with Orostachys iwarenge and creeps off the step into white-flowering Pratia angulata. (Yes, the tall sword-leaved plant is a German Iris, another plant great for sunny dry soil.)
Bottom Step – Dying crocus foliage is almost hidden by the dense growth of Wooly Thyme, more Sedum acre, pink blooming Armeria maritima, Acaena ‘Purpurea’ (not available), and Pratia pedunculata with its tiny blue star flowers. More of the Pratia Little Blue Star can be seen to right of the Thyme ‘Coccineus’ flowing off the third step.
If you are planning to create or expand your own sunny rock garden or similar area, look for other cultivars and species of the plants used here, particularly the Sedum, Sempervivum, and Delosperma. Other perennials to consider for your design include Allium, Callirhoe, Dianthus, Gaura, Iberis, Phlox subulata, and Yucca. Be sure to pay attention to a plant’s eventual height and width at maturity so that as your garden develops the plants fill in nicely and don’t become overcrowded for the design. Although all of these plants can tolerate drought or dry soil, they will need adequate moisture while getting established. Check the root ball of new plants regularly, particularly during hot, dry periods to be sure they have some moisture. If they are very dry, give them enough water to moisten the root ball and the soil around the planting hole. Usually, after a few months the plants will have extended their roots into the surrounding soil and will not need supplemental water.