If you empty out a container of daffodils in summer you will find that the old bulbs are still intact but have now formed offsets, each one capable of growing on to produce flowering stems and offsets of its own.
Look at the old bulbs of a Muscari armeniacum (grape hyacinth). They will have increased in size and produced several tiny ones, each clinging to the parent. In years to come, these will each grow on and become flowering bulbs in their own right. If left undisturbed, they will form clumps of bulbs and in time produce a beautiful carpet of bright blue flowers. Meanwhile, the flowers will have produced a generous crop of viable seeds. No wonder they naturalize so well. The same is true of alliums, which produce copious quantities of seed. The leaves spring up, looking like chives around the parent plant in spring, each little leaf with a miniature bulb at the base. Grow them on and they will produce flowers within three or four years.
Hyacinthoides spp. (bluebell) are prolific self-seeders. If you wanted to plant a new bluebell wood, you would no doubt be impatient for the results, but if you had them growing in your garden borders, you would probably be waging war on the new patches of bulbs before too long. Avoid planting Hyacinthoides non-scripta (English bluebell) near H. hispanica (Spanish bluebell), because cross-fertilization will occur with a dilution of the natural stock of English bluebells, which are less vigorous than the Spanish plant.
1. Allium hollandicum ‘Purple Sensation’ produces generous quantities of seed and will self-seed beneath the parent plant.
2. Within a short time, small bulbs have grown that can be carefully harvested in the autumn.
3. Replant the small bulbs in a pot or directly into border soil where you would like a display in the future.
Lifting and storing
Because bulbs multiply underground by producing daughter bulbs around the parent, sooner or later clumps become congested. Some species, such as nerines, flower better when they are congested, and these are best left alone for many years until flowering dwindles. When this happens, it is time to lift and divide the bulbs. Clumps of other bulbs, such as alliums, Muscari spp., narcissi, tulips and tulbaghia, are best divided every three years or so. Where they have become well established you will be amazed by the proliferation that has occurred. Lift the bulbs during the summer dormancy and tease them apart carefully, replanting the largest bulbs as needed.
All seedlings, whether they are Galanthus (snowdrop), Eranthis hyemalis (winter aconite), Muscari spp. (grape hyacinth) or bluebells, do better in border soil than in turf, where there is too much competition from dense, coarse grasses for the young plants to establish themselves, but these species will still multiply in grass, albeit more slowly. For best results, choose an area with fine grass, where competition will be less intense.
1. Eucomis bicolor produces many small black seeds. These may be sown into pots ready to be grown on for a year before being potted on the following year. They should flower within two years of sowing.
2. Alternatively, eucomis may self-seed in the pots in which they are growing. Remove the tiny new plants and grow them on in a pot in gritty compost for a year. Then repot into individual pots to flower the following summer.
Lilium regale seeds
Lilium regale will produce lots of seeds. If uncollected, these may self-seed beneath the parent plant. Alternatively, gather the seedpods, empty the contents and sow the seeds thinly in pots or trays filled with a moist, sieved, gritty compost, ready to grow on.
Lilies have another way of propagating themselves. As well as forming offsets and seeds, some lilies will produce bulbils at leaf axils up their stems. These fall off in time and form new plants when they root into the soil at the foot of the parent plant, where they will soon develop. These miniature bulbs can be lifted in autumn and potted on ready for planting out 18 months later. This type of propagation occurs most commonly on Lilium lancifolium (syn. L. tigrinum; tiger lily) and many of the Asiatic hybrids.
Another method of propagation is to collect the bulbils themselves, detaching them carefully from the stem, and plant them into small pots. Grow on for two years before planting out in the garden.