The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
American Rock Gardens
The rocks should be placed in as natural a manner as possible. When there are some boulders already on the site, it is not difficult to add others. An old stone quarry is a rock garden all prepared for minor changes and planting. Where the ground is uneven or sloping, it is not too much to imitate a rocky field, but on flat land, especially in city lots, to give a pile of rocks the appearance of Farmer Brown's barren stony pasture is a feat of great mental and physical agility. Stones native to the region are preferable, not so much because they are more cheaply and easily obtained, but for the effect of naturalness. The more the stones—after being placed— seem to have been deposited by natural forces, and thus attract little notice to themselves, the more attention will be given the plants; for this is a garden and not a geologist's pile of samples. The distance hauled is often governed by circumstances, as when carloads of rocks were transported from a New England town to Illinois. Though placed carefully on the bluffs of Lake
Michigan, the owner refers to this area as the garden of precious stones. Rocks of brilliant color, or special character, are usually to be passed by, unless red sandstone or green slate is the common local rock formation.
In picking the stones there are many to be rejected. Too frequently, because of ease of handling, the rocks chosen are too small, and the garden resembles the chip pile of a stone-cutter's yard. Few stones should be used on the finished surface that are less than a foot in major diameter. This preserves naturalness and assures stability. The extreme of size is limited by the equipment for handling, but moving boulders of several tons is expensive as well as unnecessary. There is a rock garden in New England built on a slope where no stones existed, heaped with massive slabs laid up by a derrick, in effect of the Giant's Causeway rather than a deposit by the glacier. The larger stones should be not less than three feet in shortest diameter, of a weight that two men can move with bars, and horses or tractor can pull easily on a stone boat.
Stones of very soft structure, as some slates and sandstones, will melt in several winters of frost. These should not be used in any quantity or the garden will soon look like an ice palace on the approach of summer. Very hard stones, as quartz and trap, are very durable as foundation, but offer little weathered surface, for the growth of plants and vegetation will not clothe them. Rounded water-worn boulders are difficult to place to look stable; these egg-like rocks are to be used but little. The extreme of slablike rocks is equally to be avoided—either they resemble stepping-stones when placed flat (use them all for walks) or when set on edge we have the garden of the dragon's teeth (page Jason). Of course, dressed stones, nagging, and lumps of concrete will be discarded.
