This will entail careful husbanding of all existing topsoil, removal of subsoil to the proper depth, and substitution of the topsoil in its place. A copious supply of well-rotted manure and other fertilizers will have to be worked into the soil before it is put back into the bed.
The soil will have to be well drained, either naturally or artificially. Drain-tiles placed under the bed and connected with a suitable outlet may be used, or a bottom layer of stones will be satisfactory.
Transplanting time is governed by the flowering season and local climate and soil conditions. Spring planting is better than fall planting where the winters are severe and the soils are likely to heave the plants. Fall planting is better than spring planting where winters are moderate and soils do not heave badly. Unless the winters are nearly free of frost, plants which are propagated by division and which bloom in the fall should be moved in the spring.
Do your fall planting 4 to 6 weeks before freezing weather is expected; better still, do it 2 or 3 months before, to let the plants become established by winter.
In dry regions, especially those swept by severe, drying winds, newly planted beds must be watered thoroughly soon after planting and mulched to keep in as much moisture as possible through the winter.
Hardy perennials prefer a winter mulch, especially in cold areas in which the frost penetrates to a depth greater than that reached by the roots. The mulch should be spread on just after the ground freezes. Be careful not to apply too thick a winter mulch to plants which have fleshy leaves which stay green all winter; they heat up and rot if covered deeply.
Where a snow blanket remains throughout the winter, only a slight covering of straw, leaves, or other litter is needed, just enough to hold the early winter snows.
Here is a suggestion which may not jibe with the gardener's sense of neatness, but it is certainly a good practice: do not clear away the tops of the perennials in the border until the coming of spring. The fallen tops make a fine protection for the plants themselves and keep the mulch from packing too closely about plants whose tops die every year.
There must be an unceasing attack on weeds, which grow persistently among perennials and are, more difficult to eliminate than among annuals, for which the ground may be spaded thoroughly each year.
Perennials multiply at a pace that makes their division desirable every 3 or 4 years. When they are divided a new manure supply should be worked into the soil, and it should be enough to keep the soil stocked with humus for another 3 or 4 years.
Beds among shrubbery
The stronger plants are most likely to succeed in beds among shrubbery, which usually are less well prepared for planting than gardens and borders. The principal culture in such plantings consists of weeding. Usually there is little hoeing, but a mulch may be used to keep down weeds and conserve moisture.
It is necessary to divide and reset perennials planted among shrubbery as frequently as in borders or gardens. Mulching also is beneficial, not only to the flowers but to the shrubbery as well, and a summer mulch is more practical than continued cultivation to curb weeds and conserve moisture.
Naturalized plantings are those in which the flowers are planted in a manner as similar as possible to that in which they would be likely to grow wild-the seeds sown in favorable locations and given little more attention. Naturally the plants selected for such use must be well adapted to the conditions of soil, shade, and competing growth.
Making rock gardens
Once a rock garden is built, little can be done to fertilize the soil except in an occasional pocket. Thus, the plants which serve best in such a setting are those which thrive in relatively poor but well-drained soil. A rock garden must be watched carefully for weeds, but dry, gravel-laced soil is uncongenial to the growth of many plants which, in better soil, might become troublesome weeds. Most rock-garden plants require either no mulching or only a winter mulch of gravel to prevent winter rot at the crown. They also do not have to be thinned out periodically to prevent overcrowding, as do those perennials in other settings.
Making wall gardens
Plants in wall gardens should not be too large, and growth may be checked if the soil used to fill the pockets is not too rich. The cultivation consists chiefly in eradicating undesirable plants. There is no mulching in such a planting, and the plants that survive are only those which grow in well-drained soil without protection.
Making wild gardens
Wild gardens must simulate as nearly as possible the natural conditions of the woodland. Thus the soil may not be hoed or stirred, and the gardener may not remove fallen leaves or dying stems. In addition, hardwood leaves should be spread on the ground in autumn and allowed to rot there. The fight on weeds is waged by pulling them up.