Although there are still many rock gardens in existence, they are not nearly as popular as they once were. A well-designed rock garden can be extremely attractive. Unless such garden is well executed and fit into the landscape, however, it may seem little more than a rock pile out of place.
Rock gardens, especially those that have been newly planted, require more maintenance than the average flower garden. Most weeding among the rocks will have to be done by hand because most equipment cannot be used among the rocks. Herbicides may be used sometimes, but always check plant tolerance before using them There are two basic types of rock gardens, the formal and informal designs. The formal type tends to have more straight lines, circles, squares, or other geometric forms. The naturalistic garden is based around gentle curves and more irregular placement .
Naturalistic rock placement should be done to make the rocks appear to be natural outcroppings of the site in which the garden exists. The informal rock garden is often located in a more distant, secluded section of the
landscape. The formal rock garden more likely is associated with the outdoor living areas, perhaps a feature seen from the patio or picture window.
Rock gardens often are used as a means for handling a change in grade. On steep grades the rock garden may be little more than a dry stone wall containing a few plants. Where the grade is very gentle, the rocks may be spread over a wider area. Therefore, the rocks contribute little in the way of holding soils but provide a setting for a collection of plants. The slope or change in grade associated with rock gardens is important to the plants normally grown in them, because the plants need excellent drainage.
In addition to the need for good surface drainage, provided by the rocky slope, most rock garden plants need a loose soil with good internal drainage. When constructing a rock garden, provide good soil between rocks or in pockets where plants are to be grown. Better still, take out poor soil and provide a layer of topsoil behind or beneath the entire rock structure or bed.
Few rock garden plants tolerate tight, heavy clay soil. Most rock gardens are best suited to northern or northeastern exposures, especially when small, delicate alpine or wild plants are chosen. In a southern or western exposure, not only high temperatures may be a problem in mid-summer, but rapid drying may damage plants or make frequent watering necessary.
Even in winter, the southern or western exposure is more subject to freezing and thawing as well as rapid temperature changes. These conditions may be damaging to some plants. If they can be located where there is light afternoon shade, a southern or western exposure can become more desirable.
Although one may begin designing and building a rock garden in the fall, most planting should be delayed until spring. Spring flowering bulbs might still be added, however. In northern or eastern exposures, the rock garden may contain wild flowers or alpine plants. In west exposures, plan to use such durable plants as sedums, rock cress or creeping phlox.
Rock Garden, Rock Garden Design and Construction by North American Rock Garden Society.
