By their nature, most rockery plants are miniature in height, foliage, and flower. Alone or combined with miniature bulbs, the smaller perennials and annuals, and the tiniest shrubs and trees, they invite close-up enjoyment of their daintiness in these small plantings. Rocks and rock-loving plants have a perfectly natural way of blending and contrasting, each bringing out the best qualities in the other.
Although they’re of different design and construction, rock gardens and dry walls are usually planted with the same or similar plants, and given similar care. Paths, pavements, and garden steps are close kin. But pools and water plants, even though they are often included in rock gardens, are a separate subject, and are covered in Chapter 12.
ROCK-AND WALL-GARDEN DESIGN
“Cemetery,” “penitentiary rock pile,” “collection of geological specimens”—these and other unflattering phrases have been used to describe what a rock garden should not be. This eliminates the artificial rock-studded circle in the center of a lawn, rocky slopes with nothing to back them up, isolated paths and steps that have nowhere to go, stone-stuffed piles of loam with no conceivable excuse for being where they are.
What a rock garden should be, is an integral part of the landscape, completely at home and in harmony with its surroundings, and having a sound reason for its existence. Except for a few functional affairs such as walls that retain terraces and steps that climb banks, their purpose is mainly ornamental. Neither rocks nor plants are featured at the expense of the other. Both work together to create the picture—the plants to add brightness, vitality, and life; the rocks to help provide favorable growing conditions and a naturally suitable background for their display.
Designs for these gardens can be, as for others in the landscape, formal or informal. The fixed geometry of walks, walls, and raised beds in formal pattern are seen less frequently. But this is a type of rock garden that might be placed advantageously in even the flattest, barest suburban lot where naturalistic plantings and rocks look out of place. If you long for a rock garden, try something like this in either classic or contemporary style.
Informal rock gardens must, above all else, look convincingly natural, as if the glaciers might have placed them. This is equally important to a cluster of bulbs at the base of a single, half-sunken boulder; the arrangement of rocks and plants on a small slope; or the series of rocks that line a winding path. Builders of ambitious rock gardens are often advised to study the nearby countryside and use it as a guide.
Designs for Naturally Uneven, Rocky Land
This type of terrain makes a natural setting for rock and wall gardens of all sizes, shapes, and contours. Generally, the design is informal and naturalistic. I don’t know whether it’s really easier to work out such designs in miniature, or whether I merely think it’s easier because that’s the kind of land I have to work with. So far, we’ve never disagreed with Nature about the placement of a rock outcropping, for example. The few we’ve uncovered and cleaned up have almost told us what and how to plant.
A small existing slope or bank is a perfect site for a composition of rocks and rockery plants, or, if you prefer, a retaining wall between the two levels with plants grouped at the bottom or top, or planted horizontally in the cracks. Or consider a series of ledges that create small, irregular terraces.