Rock Garden Design
Basic instructions on designing a rock garden including planning, selection and placement of rocks, and plant selection and arrangement.
Rock gardens offer fascinating possibilities to express your creativity. A well-designed rockery will not only add interest to an otherwise unremarkable landscape, but can also provide an attractive solution for a difficult gardening problem. A rock garden can adorn a hard-to-maintain slope that cannot be easily managed with turf or can be an attractive focal point where dry, poor soil or deep shade limit your gardening options.
Even the most natural looking rock garden must start with a good plan. Make a sketch of the shape of your proposed garden, with measurements, and determine where rocks will be placed. It is always best to use native rock when available and suitable for the intended project. If you must bring in rock, choose a type that is compatible with the landscape. If you are planning to build a rock wall garden on a steep slope, you will need stones that have flat surfaces. If, on the other hand, the slope is gentle or less than three feet high, you will have more options on where and how to place your stones. Experiment with rock placement on paper and then on the ground to achieve the most aesthetically pleasing arrangement. For those who want the "look" without all the labor, there are "light" rocks, developed from composite material, available in many areas.
Select the varieties of plants you want to include in your garden and decide where they will be placed in relationship to the rocks. The plants you choose will be determined by the type of rock garden you want to create as well as your climate and exposure. If you have a sunny, fast draining spot with rocky soil, you should choose among the many succulents and cacti species. For colder climates there are hardy sedums and attractive rosette-forming succulents like hen-and-chickens (sempervivum). For shady rockeries, you can choose among the many varieties of ferns, mosses, and shade-loving perennials. An alpine rock garden will contain plants that are native to stony soils and cool temperatures. To keep them dwarf, the soil should not be too fertile. Some common alpine plants include alpine anemone, alpine pink, alpine rockcress, edelweiss, alpine for-get-me-not, and savory. Whatever varieties you choose, remember that the size of the plants should be on the same scale as the garden itself. Tiny plants are most attractive in a small rock garden; tall perennials and dwarf shrubs are best suited in a large, wide, contoured garden. Be careful about introducing an aggressive or rampant growing ground cover into your rock garden. They will quickly crowd out some of the finer plants. Even though many of the alpine and dwarf plant varieties are slow growers, their beauty will reward your patience.
When you have collected or purchased your rocks, plants, and soil for filling around the plants, you are ready to begin. Whether creating a wall or a small garden, start at the lowest point and work toward the highest area. If you are contouring the landscape, save the soil you remove in one location to add height to another area. When constructing a rock wall make sure the wall is slanted back toward the slope one inch horizontally for each vertical foot of wall. Tilt the flat surfaces back toward the slope to catch the water. All rocks have a “better” face and a more stable side. With luck, the most stable placement of your rocks will showcase the more interesting face. Try to bury at least half of each rock in the soil so it will be firmly anchored and have a more natural appearance, not just sitting atop the ground.
The best time to transplant seedlings is while you are arranging rocks; the rocks will help anchor and protect the plants’ roots. Water the plants and soak the soil around the rocks thoroughly to settle and compact the soil. Any soil added as fill should be wet.
Slugs and some insect pests may find the cover of rocks to be the perfect hiding place. Be on the lookout for possible damage while young plants are becoming established. Be careful when removing weeds from your garden. Remember that some plants may have shallow roots and could be easily damaged during weeding.