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.
Plant roots in spring in warm, well-drained soil protected from the wind. Allow two feet or more between plants. In autumn dig and store in a dry, airy, frost-proof cellar. From Washington southward the plants may be left out during the winter if protected somewhat with leaves or litter.
Sow seeds where the plants are to remain in ordinary garden soil well exposed to the sun. Thin to six or eight inches. Plant successionally for later blooming.
May be-propagated by seeds. Greenwood cuttings, which may be taken at any time, are more, often used. The plants succeed under the same general treatment as geraniums and fuchsias.
Plant seeds in spring in moist, partially shaded places,, preferably where the plants are to remain.. Thin the plants to stand four inches apart and during the summer thin out the smaller ones, leaving the large ones eight inches or a foot apart. These will flower the following spring and will re-seed abundantly. The plants will stand even stiff clay and full sunlight.
Most varieties can be treated the same way as Canterbury Bells, which see. The perennial sorts may be started in this way and after their establishment may be divided. They will succeed in sunny or partially shaded places and seem to prefer light, rather rich, friable, moist soil.
Plant the bulbs in autumn in ordinary potting soil and keep in a cold place until desired for successional blooming, when they may be brought into the mild greenhouse. Provide ample drainage in the pots-or flats and water sparingly until blossoming time. After growth starts, the plants require-about six weeks until the blossoms appear. The bulbs may be dried off like other species, of bulbous plants, but new ones are usually so much more floriferous and are so cheap that they are generally preferred.
In early autumn plant the bulbs four inches deep in rich, moist, but well-drained, sandy loam, allowing from a foot to eighteen inches between bulbs. The beds should be out of the direct rays of the sun, either shaded by trees or shrubs during the heat of the day or planted on a northern exposure. Since the bulbs form numerous offsets they should be dug every second or third year after the foliage has died down. After cleaning and dividing the clumps, store in a cool, airy, dry place until planting time.
Blooming plants may be grown from seed in about a year. Cuttings are more frequently used, since they are always obtainable and are very easy to root. The plants will do well in any soil and in the ordinary temperature of the living-room. Cuttings rooted in early spring should produce blossoming plants by Thanksgiving Day, and cuttings taken in September should bloom before spring. After blooming, the plants are generally thrown away, but they may be made to bloom again after a rest, during which the plants must be kept in cool quarters and watered sparingly.
Plant roots in deep, rich, moist soil in spring. The large-leaved kinds do best in partial shade, where the soil is very moist. The plants may be allowed to remain for years, during which time they generally improve. Some species produce seed freely. If seedlings are needed, the seed should be sown as soon as ripe.
Sow the seeds in midwinter under glass, and when about an inch tall transplant to two-inch pots and, if necessary, to a larger size before transplanting in the garden, where they should stand about fifteen inches apart in light, rich soil in an open, sunny situation. The seeds are very slow to germinate.
See Hyacinth, Summer.
Sow seeds as soon as ripe in the autumn, covering them an inch deep in a nursery bed, where the plants may remain until two years old. The seedlings should be thinned to six inches in the row and be undisturbed, since they do not bear transplanting well. Select for permanent quarters a fairly rich, rather neavy soil, and a situation in which the plants may remain undisturbed.
Transplant plants from the garden in autumn, allowing plenty of room in the pot, saving as much root as possible and cutting back the top severely. The firm green parts removed may be used as cuttings. They easily strike root and are of easiest management. They need only ordinary soil, and if kept growing vigorously should bloom for months. A greater amount of bloom is produced by allowing the plants to become pot-bound after they have reached blooming age. Plants which have been grown from cuttings taken in winter, and which are in three or four-inch pots, may be set in the garden after danger of frost has passed. Allow nine inches for the smallest bedding varieties and eighteen inches for the large ones.
Sow the seed in the autumn where the plants are to remain, because they do not bear transplanting well, unless the operation is done while the plants are very small. The bed should be covered with a light mulch of leaves or straw, which must be removed in spring. They do best in rather light soil, and, according to kind, should stand from six to twelve inches apart.
Plant the corms two inches deep in heavy soils and four inches in light. Successional planting should commence with the smallest corms as soon as the soil can be worked, and end with large corms planted about midsummer. If confined to beds, the first-planted bulbs may be set twelve inches apart, the later-planted ones set in the intervals; six inches apart is close enough. In late autumn dig, dry, clean and store the corms in a cool, dark, dry, airy place. Seeds are often used to produce new varieties. They are sown thickly in spring, a few radish or turnip seeds being planted with them to mark the rows. No flowers can be expected the first season from seeds. Even the second season some corms will fail. These should be saved for a third year's planting, because they often produce superior flowers.