Making a Rock Garden

by H. S. Adams

plant of Saponaria ocymoides will spread out over four square feet of soil, and thus fill completely a moderate-sized pocket, whereas to conceal the same amount of ground three dozen auriculas might have to be used. The same is true of the white rock cress (Arabis albida). So, too, with a crevice. A single plant of one of the trailing stonecrops would fill it, perhaps, when a number of rosettes of the smaller kinds of house leek would be called for.

Tall plants, like the foxglove, may sometimes be used, in a small group, at the end of a bay on the level of the path; but they are best placed behind the rock work, as a background, or as dominating features of the entrance or exit of the garden. At the entrance or exit such bold plants make a good bridge between the rock garden and the outer grounds. Spreading and trailing plants should be

placed a foot or more above the path level and most plants with tufts or rosettes of foliage. If the path is broad enough some of the wide-spreading plants may go at the base of the rocks, but the rule there is to use those of moderate spread, with a few tufted plants and some that grow upright, but are not tall, to lend variety. When the path is of flat stones, irregular in both size and placing, this growth should fill all the soil space—even between the stones. Such a path will be found more than worth while, and not as much of an undertaking as it may seem.

Obvious considerations are that plants with a decided hankering after moisture or shade should be favored in the matter of location, though it is astonishing how adaptive many of them are.

Do not plant the weak next to the strong. Unless you are a gardener of

eternal vigilance, the weak will have the worst of it before you realize what a mistake you have made.

Finally, do not forget that planting is not the end; it is only the beginning—of planting. So long as the rock garden exists there will always be planting. Normal mortality will necessitate some, there will be thinning out, and time will suggest additions and more or less rearrangement.

And with the planting goes on the continual care, much of which can be done in the course of the daily walk in the garden, and therefore the loss of time will not be felt. Water in case of a real drought, but use a sprinkler, and do not stop until the ground has been soaked to a depth of a few inches. Mere surface watering is bad enough in the ordinary garden; in a rock garden it is a fatal error, as the growth of roots near the top of the soil

leaves the plants in no condition to stand the full force of the summer sun.

Go over the garden thoroughly once a year and all the time keep a sharp lookout for weeds. If the soil is heavy, top-dress with grit in the fall. Grit is good for rock plants. Stone chips placed around a plant will prevent too much dampness lodging about the collar in winter. Watch out for weak spots after very heavy rains.