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Are you considering a rock garden? Try these plants for coverage and color — they’re tried and true, and they’ll provide delightful highlights among boulders and stones.
Whether you live on the West Coast or in New England, an arid region or one with plenty of moisture, there’s a rock garden style for you. In fact, these unique structures can be the focal point of nearly any type of garden—provided you incorporate the appropriate plants. Be sure to select those that are hardy to your region, and those that can withstand the occasional period of low moisture. Your local garden center professionals can help you choose the best plants to make your rock garden flourish. They can also recommend the proper soils for your particular use.
Given the appropriate soil, perennials will thrive in rock gardens. If you incorporate flowering perennials, select varieties that will bloom in succession, just as you would in a standard garden setting. When one plant’s flowers begin to fade, another is just opening its display, and the profusion of color can last for season upon season.
Ground—or rock—hugging perennials can quickly form mats and carpets of lush green foliage that soon produces swaths of blooms. Look for varieties like Arabis species (rock cress), which fills in crevices with evergreen foliage and produces clusters of tiny, white, four-petaled flowers that cover the plant in spring. Iberis sempervirens (candytuft) is a similar plant, with snowy white flowers that fade to a light pink.
Veronica bombycina (woolly Turkish speedwell) produces a ground cover of fuzzy, silvery foliage that maintains its color all year. During spring, small, light blue to periwinkle blooms appear above the leaves, covering the plant in a blanket of soft color.
Taller blooming perennials like Aquilegia (columbine) and Penstemon (beardtongue) add scale to a rock garden setting, sending up slender stalks that support spurred and trumpet-shaped flowers. The blue-and-white columbine, the state flower of Colorado, is among the most recognizable. But the genus boasts such a variety of colors and habits that selecting just a few will be difficult. Choose from white or yellow to bicolor red-and-yellow to the deepest of purples.
Penstemon flower colors rival those of Aquilegia, ranging from true blue to rosy pink to deep red-orange and rich maroon. The ‘Husker Red’ cultivar features dramatic, purple-red foliage and delicate white flowers, providing a pleasing contrast among green-foliaged plants.
Succulent plants provide a surprising range of textures and colors that can outcompete party-colored annuals. A happy collection of hens and chicks (Sempervivum tectorum) presents a bouquet of sturdy foliage that can resemble the finest flowers. “Mother” plants—the hens—form rosettes in colors ranging from light green to the deepest red-purple, with many leaves emerging green with reddish tips. These central plants produce “chicks,” which are smaller rosettes that crowd around their mother. Bright, rayed flowers appear on sturdy stalks.
Delosperma species (ice plant) have exploded in popularity over the past several years, with many stunning introductions coming from programs in the Rocky Mountains. This fast-and-low-growing groundcover forms a rich, green carpet of small, evergreen, succulent leaves that resemble swollen needles; the foliage supports daisy-like blooms in a riot of colors in spring. Flowers may reappear periodically through warmer months until autumn.
Sedum species (stonecrop) grow in such a wide range of colors, textures, habits, and sizes that a rock garden composed entirely of Sedum would be a standout in any setting. They’re easy to grow, and many produce white or pink flowers that attract butterflies in summer and fall. Several selections are sold in tile-like combinations—sort of like sod—making it even easier to cut to shape and tuck in between rocks.
Nothing provides a sense of permanence like the boulders and stones in your garden. That is, nothing but woody plants, which can enhance that impression and create an instant perception of history.
Low-growing, trailing, creeping, needled evergreens are natural choices, and once they’ve established, they appear to have grown there since time began. They form a foundation for colorful flowering perennials, but they also provide attractive color on their own.
Smaller Abies species (fir), such as A. koreana ‘Compact Dwarf’, A. concolor ‘Charming Chubb’, and A. nordmanniana ‘Golden Spreader’, are specifically recommended by the North American Rock Garden Society. Colors range from rich green through silvery blue to a brilliant gold.
Picea abies ‘Nidiformis’ (bird’s nest spruce) is a slow-growing favorite, both for its dwarf size and its dense, rounded habit.
In larger sites, Juniperus species (juniper) can be incorporated both for coverage and height. J. chinensis ‘Angelica Blue’ is a spreading variety with intense, bright blue foliage. It reaches about 5 to 6 feet in height and spreads up to 10 feet. A more compact, but just as intensely blue selection is J. squamata ‘Blue Star’, which forms a neat mound about 2 to 3 feet tall by 3 to 4 feet wide. ‘Blue Rug’ creeping juniper forms a dense groundcover only about 6 inches tall, but reaching up to 6 feet wide.
Your favorite flower colors will always be your go-to, but when you’re selecting plants for a rock garden, keep in mind that the background—the palette against which those flowers will be framed—is a bit different from a normal garden. Rather than gardening amid rich, deep earth or lush green foliage, you’ll be planting among rocks that may tend to carry lighter tones. Buff, cream, and shade of gray are common, but you may also choose boulders or stones that blush in pinks and rose colors. In Western regions, however, the most popular and most readily available rock may be deep red, or even near black. So if you want your flowers to pop, choose the colors accordingly.
Rock gardens are no longer limited to mountain and desert locations. With a broad range of plants from which to choose, you can design and plant the rock garden of your dreams in nearly any setting. As long as sufficient drainage is supplied, and the plants are selected for the appropriate region, microclimate, and sun/shade conditions, why not experiment? You may discover that your favorite garden plant shines among the rocks.
To create your perfect garden, find a landscape professional near you.