• Aloe (Aloe barbadensis and other species). Grow these as annuals or as specimen plants in containers, to be moved to windowsills inside for the winter. Many exotic aloes from South Africa are now commonly available, in a wonderful array of shapes and colors.
• Chives (Allium schoenoprasum). Early spring bloomers, pink pops of color top the strappy leaves. This plant will toss some seed around, but not usually in a troublesome way.
• Pinks (Dianthus spp.). These little treasures show up among bedding plants every spring in a wide variety of pink, purple, white or magenta. The petal edges are usually fringed or look like they were cut with pinking shears.
• English lavender (Lavandula angustifolia). This hardy herb-garden classic earns its place on the rock wall with its intense fragrance, color and drought tolerance. Its soft mounds and flower spikes offer good contrast. There are many, including white-, purple- and pink-flowered forms, and dwarf varieties.
• Oregano (Origanum spp.). Try the ornamental side of this large genus, including ‘Kent Beauty’, hardy and well-behaved; the more tender Dittany of Crete; ‘Hopley’s Purple’; and other showy varieties.
• Prostrate rosemary (Rosmarinus officinalis ‘Prostratus’, ‘Santa Barbara’, ‘Severn Sea’ and other trailing or creeping varieties). In mild climates, this fragrant herb is an excellent landscape plant for cascading down a wall; in harsher environments, perch it in a clay pot, and move it to a protected spot in winter.
• Santolina (Santolina chamaecyparissus, S. virens). Soft clumps of foliage, available in both gray and green varieties, are topped by numerous bright yellow button flowers in early summer.
• Winter savory (Satureja montana). This dark green, clumping perennial herb will thrive in rock-wall conditions. After a few seasons, the stems may start to get woody, so take cuttings and replace it occasionally.
• Thymes (Thymus spp.). Grow them all, or as many as you can find, as these are star performers on a rock wall. They are generally low-growing. They spread in clumps and are heavy bloomers, and their fragrant flowers are favorites of bees. Try ‘Pink Chintz’, ‘Doone Valley’, woolly thyme, caraway thyme and lemon thyme.
• Succulents. This vast category of plants includes far more than just prickly cacti. Suitable for growing in dry spots of a rock-wall garden are the annual moss rose (Portulaca grandiflora), sedums, echeverias (one of a number of genera that form “hen and chicks”), graptopetalums, and many others worth seeking out. They are excellent companion plants for herbs, love the rocks and can be dramatic focal points as well as crevice fillers.
Kathleen Halloran writes and gardens in Texas.
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