Rock Gardening: Creating a Miniature World of Plants
by David Salman
There are many styles of rock gardening. Europeans were the first to develop rock gardening as a way to mimic the Alps and other European mountain ranges and plant them with alpine plants, and this style of rock gardening remains extremely popular here and across “the Pond.” But rock gardening has evolved and reflects an expanded interest in small growing plants, many of which are not of alpine origin.
Rock gardens can feature a wide variety of xeric plants.Rock Gardening in Arid Climates
Rock gardening is my favorite style of gardening, and the front yard of my Santa Fe home is planted as an expansive rock garden with a wide variety of xeric plants, large and small. Having been a gardener in the Rocky Mountains for most of my life, rocks and plants are a natural combination that I see all around me. I have adapted my style of rock gardening to reflect a xeric palette of plants best suited to the searing high elevation sun and dry growing conditions here in New Mexico. That, and I can’t afford the water needed to keep alpines happy.
The Importance of Rock
The rocks in rock gardens are just as important as the plants. For a more natural look, I think it is important to use a single type of rock as the foundation of a rock garden. And these rocks should be used in conjunction with soil berms (small hills) to give the rock garden topography that simulates a mountain and valley environment. In dry climates I always recommend sloping the rocks back into the slope so to facilitate water flowing into the berm. In moister climates, rocks should be arranged to shed water away from the berm.
Aloinopsis 'Psychedelic' is a South African succulent that works well in rock gardens.A Well Drained Soil Mix
It is of vital importance to create a fast draining soil mix to build your berms with because many rock garden plants need excellent drainage. Especially in winter when a soil that is too moisture retentive can cause root rot. I like a mix of half coarse sand/crushed gravel with a good garden loam amended with some compost and rock dust (a trace mineral-rich blend like Planters II). Then I mulch with 1 to 2” thick layer of crushed (angular) 3/8” diameter gravel.
Rock Garden Plants
Over the years, I have developed a palette of small growing perennials, cold hardy succulents (native and South African) and cacti as a basis for the xeric rock garden.
Some of my favorites include:
Agave toumeyana ‘Bella” - a cold hardy, miniature century plant
Aloinopsis ‘Psychedelic’ (and other South African succulents) – extravagant flowers and incredible, other worldly succulent foliage
Aquilegia flabellata ‘Nana’ – a tiny blue flowered Columbine
Arenaria sp. Wallowa Mountains – a deep green xeric moss look alike
Delosperma ‘Gold Nugget’ – a sub-alpine Iceplant for north facing crevices
Dianthus ‘Nyewood Cream’ – incredibly fragrant
Erigeron scopulinus – a very rare native fleabane with cheerful white daisy flowers and tiny bright green leaves
Geranium dalmaticum – fantastic miniature perennial geranium
Phlox kelseyi 'Lemhi Purple' is a stunning small grower.Hymenoxys scaposa and H. acaulis v. ivesiana – cheerful long blooming yellow daisies
Penstemon pinifolius ‘Compactum’ – brilliant scarlet flowers over evergreen foliage that resembles tiny pine needles
Penstemon virens – small and colorful Beardtongue
Phlox kelseyi ‘Lemhi Purple’ – a stunning small grower with fragrant blue and dark blue flowers
Thymus neceffii – fantastic foliage and flowers
Veronica bombycina – superb nearly white foliage and bright blue spring flowers
There as so many great rock garden plant species, but these are really good, easy-to-grow plants to get started in this fascinating style of gardening.
Text and Photos by David Salman
'Blue Spruce' Creeping Sedum (Sedum reflexum) is a standout among low-maintenance Sedums. This easy-to-grow and eye-catching features succulent blue-green foliage, much like little spruce needles! A pollinator favorite, it is covered with small star-shaped yellow flowers in summer for over a month. A great evergreen groundcover where low maintenance, drought-tolerant, deer-and-rabbit-resistant plantings are desired.
'Cape Blanco' Creeping Sedum (Sedum spathulifolium 'Cape Blanco') is sheer elegance with unusual pewter, powder-blue succulent foliage in a well-behaved groundcover. Clusters of tiny yellow flowers cover the plant in summer. Cape Blanco is an award-winning standout. Easy-to-grow and pollinator-friendly this North American native is a must-have!
Fast-growing, and colorful, 'Angelina' Creeping Sedum (Sedum rupestre) adds a dazzling highlight with colors from chartreuse to golden yellow. Easy to grow, it will spread quickly as a drought-tolerant groundcover. Bright yellow star-like flowers bloom in summer and foliage turns golden-orange in autumn. A great pick for rock gardens, dry borders, and large expanses of ground that need planting.
A soft orange-flowered selection of pineleaf beardtongue, SteppeSuns® Sunset Glow Penstemon (Penstemon pinifolius) is a native cultivar that starts flowering in late spring and attracts numerous pollinators and hummingbirds. Reminiscent of Colorado summer sunsets, its long-lasting blooms add a warm glow to dry area gardens. Finely textured evergreen foliage forms a compact mound for year-round interest.