The time to make a new rock garden is any time when the work can conveniently be tackled. Rock plants, as already mentioned, are mostly raised in, and can be set out at any time if handled carefully. A good time to choose in many ways is late summer, when most rock plants are resting, i.e., not in full flower, and are not likely to suffer from a move so much as when the are all open. Also, late summer is a period when, if ever, the home gardener can take a little rest from his ordinary labours. Plants have all reached their flowering quarters, with the exception of those to be flowered in winter under glass, and except for , there is not much “ extra “ work to be done in the main flower garden.
However, a new rock garden can be made at any time, and in the same way it would be possible, though not advisable, to remodel a rock garden at any season. Gardeners generally choose, however, to remodel the rock garden, when necessary, just before the winter, when alpine plants are preparing to sleep beneath a canopy of snow.
After a rock garden is made and planted, it will take a few months or the plants to become established. By that time it will be necessary to keep a sharp lookout for weeds, and also to watch the vigorous growers among the plants and see that they do not encroach on
the slow growers. Rock plants do not like to be smothered by decaying humus. From time to time, therefore, the pockets must be carefully gone over, and all old decayingtrimmed away. Leaves that blow on to the pockets from nearby trees in autumn are particularly dangerous to the health of alpines.
Occasional top dressings of gritty soil, or stone chippings, or, in the case of lime-loving plants, of crushed mortar, should be given towhich are bared by rains or frost; and any plants that have been loosened in the soil by weather action should always be made firm again.
Whenever a plant has finished flowering, it should be attended to according to the type. Carpet plants of vigorous habit such as arabis, the white rock cress, should be cut hard back after flowering, or they will quickly become a nuisance. If an increase in stock is desired, the pieces cut away can be inserted in sandy soil in a shady part of the garden, or in a frame or propagating pit, where they willwell in time for autumn planting.
Dead flowers should generally be snipped off with scissors; but if rock plants are to be raised from, some of the can be left to ripen on the plant. Most rock plants grow readily from such freshly gathered ripe , if it is sown at once, though in some cases it is better to wait until the following spring before . A few rock plants have decorative seed heads, and in such cases they should, of course, be left to ripen on the plants.