by Ken Lain, the mountain gardener
Stones in the garden are pretty, but their colors and forms emerge dramatically when low growing, drought-tough plants are added amongst them. There are many plants that will grow between rocks, but these rockery classics are strong favorites of local gardeners.
Mountain gardens are mostly exposed to full-sun with fast-draining soil, so this list of rock garden plants is geared to sunny mountain locations. If your rock garden is shaded, there are plenty of plants suited for it, but you’ll have to visit the garden center for that list.
All choices are cold-hardy at our local zones, 6 & 7.
Small Plants: “Think Small” in plant selection if you have just a small space in which to garden. Luckily, the choices here are plenty and varied. There are many small rock garden plants whose delicate beauty is quite exquisite.
Keep in mind that features such as retaining walls made of small stones also may house rock garden plants. Small specimens such as Hens & Chicks are indispensable for planting in the crevices of stone walls. Bright cascading beauties such as yellow alyssum are ideal for planting in the tops of walls, allowing them to spill down the sides. The effect of these plantings is to soften the otherwise rigid lines of a sterile barrier.
Small Rock Garden Plants
- Angelina stonecrop
- Blue fescue ornamental grass
- Creeping phlox
- Creeping thyme
- Dragon’s Blood stonecrop
- Hens & Chicks
- Ice plant
- Pasque flower
Medium Plants: Think “Goldilocks” as in the fairy tale, and look for nothing too small, but not too big, either. So, here are the rock-loving plants that are just the right size, or “medium”.
One favorite is columbine; the shape of its flower is fascinating. Another is coneflower (Echinacea), which acts like a mountain wildflower. The silver leaves of rose campion easily soften a rocky landscape.
Medium Rock Garden Plants
- Autumn Joy Sedum
- Black-eyed Susan
- Blue Rug Juniper
- Purple fountain grass
- Rose campion
- Shasta daisy
Large Plants: Think “Proportion”
The next best thing to having the Hanging Gardens of Babylon in your yard is a steep slope with boulders and eye-catching rock garden plants. This is an example of turning what could be a landscaping nuisance into the bright spot in your yard. Big spaces scattered in boulders calls for the bigger plants. Just remember that the idea is to keep everything in proportion, which is why the word “boulders” is used here rather than “rocks.”
Rugosa Rose was used by our grandparents, and is equally hardy today, but with blossoms of many more colors. Another healthy specimen for large rocky spaces is rock spray cotoneaster. For Japanese-themed gardens a good evergreen choice is the mugo pine.
Blue Lace Russian sage and lamb’s ear are more delicate-looking than the other plants in this section but do offer some height.
Large Rock Garden Plants
- Blue Lace Russian sage
- Lamb’s ear
- Maiden grass
- Mugo pine
A well-planned rock garden provides a flow between rocks and plants, allowing them to work together in elevating the impact of one upon the other. Showy plants draw attention to the stones, which, in turn, offer a delightful framework to show off the plants in their best light.
My favorite book on rock gardens is a classic from 2009 and worth its space in every gardener’s library: The Rock Garden Plant Primer: Easy, Small Plants for Containers, Patios, and the Open Garden by Christopher Grey-Wilson.
Until next week, I’ll be here at Watters Garden Center helping friends plant amongst the rocks.