This section is from the book "How To Make A Flower Garden", by Wilhelm Miller. Also available from Amazon: The Well-Tended Perennial Garden: Planting and Pruning Techniques.
Sow seeds in poor soil well exposed to the sun as soon as the ground becomes warm. Thin the seedlings to stand eighteen or more inches apart. Dwarf varieties should stand closer. In rich soil the colours of the foliage and of the flower heads are less brilliant.
Sow seeds near porches, verandas, or very large trellises. They may be started under glass in pots and the seedlings transplanted when the weather has become settled. The perennial tuberous roots may be used after the plants have become established, or cuttings may be rooted. From Washington southward the tops may live over winter.
Plant the bulbs like those of Scilla and Chionodoxa.
Sow seeds in late winter or early spring in the greenhouse or mild hotbed. When the plants are large enough, transplant to small pots and make one or two shifts before setting in the garden when the weather becomes settled. Allow four or more feet between plants. Select a warm place in ordinary garden soil. After becoming established the plants may be propagated by division.
Sow seeds in mild hotbed or greenhouse in early spring and transplant to small pots. When the weather becomes settled plant in ordinary soil eight feet apart as a background for smaller plants. Dwarf varieties may be set four feet apart. If desired, established clumps may be divided.
See Cress and Aubrietia.
In early spring sow seeds where the plants are to remain or in a border for transplanting. Allow about eighteen inches between plants, which will form clumps. These may be divided when necessary for further propagation.
Plant the rootstocks in any good soil, rich, sandy loam preferred. Moisture and shade are favourable. The plants need no further attention than annual manuring, and should be undisturbed for years.
See Chapter XVIII (Roses. I. Where Shall We Plant Roses?).
Sow seeds in spring either in the garden or earlier under glass. Transplant as the plants become large enough, either to pots, nursery beds, or to permanent quarters. Any soil or any exposure suits them. After once becoming established the clumps may be divided in spring.
Sow seed where the plants are to remain. Rather moist, rich soil is most favourable. Very likely to become a pest from the spread of its underground stems.
Sow seeds in late winter; transplant seedlings when about two inches tall to small pots. Keep them growing steadily; avoid any kind of check. Set in light, rich, deep, moist soil when danger of frost has passed. They need about eighteen inches space. Seed may also be sown where the plants are to stand and the excess thinned out. For winter bloom the seeds may be sown in midsummer or later, and the plants kept growing steadily in rather frequent shifts of pots until they approach the flowering stage, when they may be allowed to become pot-bound.
Sow seeds in late winter in a greenhouse or hotbed; transplant when an inch or two tall to small pots, and again if necessary before setting in ordinary soil eighteen inches apart, after danger of frost has passed. Greenwood cuttings may be easily rooted in a warm soil or in the greenhouse.
See Sage, Scarlet.
Plant the bulbs in mid-autumn in good garden soil, in beds or upon the lawn, and leave them to themselves. If desired to remove them, dig after the foliage has turned yellow, dry in the shade and store in a cool, airy room until planting time.
Sow seeds in mild greenhouse or hotbed during winter or early spring; transplant to flats when large enough, and to the garden when the weather becomes settled. From four to eight inches are the usual distance for planting. The soil should be sandy and well drained, especially if the plants are to remain outdoors during the winter, which some may. For further propagation, offsets are usually employed. They are taken in summer or autumn and from their increase during winter a supply should be ready by spring. They need little care.
Sow seeds where the plants are to remain or in a mild hot-bed for transplanting; first to small pots and later to ordinary garden soil. Allow about eighteen inches between the plants. Select some part of the garden where the plants may self-sow or where the volunteer seedlings will not be obnoxious as weeds.
Propagation by seeds is slow. Use divided plants when possible. Plant in partial shade in fairly rich, well-drained but moist soil. Good among rocks. The leaves die after the plants flower.
For winter ornamental purposes sow the seeds during the previous February or March in ordinary potting soil; transplant the seedlings to small pots when about two inches tall, and give frequent changes of pots as root development seems to demand. By Christmas time the plants should be in four- or six-inch pots. They may be managed as easily as geraniums, and will stand as much bad usage. A new lot of seed should be started each year, since the plants become bare below as they become large.
Sow seeds in early spring under glass and transplant the seedlings to small pots or flats when large enough to handle. When the weather becomes settled place the plants about a foot apart in the garden, allowing about a foot between the smaller kinds and eighteen inches between the larger. Any garden soil. These plants should blossom in late summer, if not earlier. For earliest spring blossom and for winter use the seeds may be sown in late summer, the plants that are to bloom during the winter being removed before cold weather, the others, which are to blossom where they remain, being protected with a light mulch of straw or leaves until spring.