Creating a Rock Garden
Photographed by Kindra Clineff
Although vacationers flock in summer to Rye’s beaches, Wallis Sands and Jenness, for cool water and hot sand, there is more to this town’s terrain than the seashore—there is also abundant granite ledge, the most familiar intrusive igneous rock, which appears in vast outcroppings throughout the Northeast and chiefly in New Hampshire. The mineral grains of granite, easily visible, give the rock its characteristic speckled look.
After 25 years, my Rye garden, which covers less than an acre and is a block from Wallis Sands, has matured. It includes a lawn, flowerbeds of perennials, flowering shrubs, vines, and trees to line the property, in the English garden style. But turning the granite outcrop on my land into an English-style rock garden proved to be challenging because it is in the shade.
Through trial and error, I learned to look for indented areas in the granite where vegetation (usually weeds) was already growing. The green growth signaled to me that the soil could be used for planting. After removing the weeds, I amended the soil with compost.
The following plants thrive in my shady rock garden and contribute to the look and feel of my English-style garden:
Midsize ferns such as maidenhair fern (Adiantum pedatum) are a good choice for shady spots. They have no flowers but the foliage adds a touch of color to the garden. Maidenhair’s light green fronds reach a foot and a half in height.
Hosta also thrives in a shady, rocky area if it receives enough water. An easy small blue hosta cultivar is ‘Blue Cadet’. ‘Golden Tiara’ hosta fits in a spot with little sun to bring out the yellow in the leaves. ‘Francee’, an old cultivar with white-edged green leaves grows large and adds structure to the garden.
A useful plant on an outcrop is astilbe, which tolerates some shade. Astilbe forms clumps of foliage topped by feathery plumes of pink, red, white, or rosy purple florets. It looks wonderful when planted with hostas or irises.
Heartleaf bergenia, also known as pigsqueak, fits well into soil pockets among rocks. Thick flower stems tipped with clusters of bell-shaped, rose-pink flowers emerge from clumps of large, glossy cabbage-shaped leaves. This bold plant can reach one foot high and puts on a show in a rocky area.
‘Silver Mound’ artemisia looks attractive among rocks, its fine, silvery blue-green foliage harmonizing with the gray stone. This plant grows about 12 inches high, 18 inches wide, and prefers some sun.
Groundcovers add a carpet-like effect to a rock garden. Maiden pinks (Dianthus deltoides) bring color along with texture. The cultivar ‘Zing Rose’ spreads a little each year, producing tiny pink carnation blooms that last almost all summer. Sedum acre is a good choice to cover an extensive area. This low, moss-like, yellow-flowered species spreads quickly, climbing rocky areas with ease.