Growing bulbs in the spring can be an expensive adventure when buying new bulbs every year. Bulb propagation is a less expensive method of growing spring bulbs. The division of a bulb is considered a modification of the layering technique used for plant propagation, says the Virginia Cooperative Extension.
The true bulb, says the University of Illinois, has five parts: the basal plate, fleshy scales, tunic, shoot and lateral buds. The basal plate is the bottom of the bulb from which the roots grow. The fleshy scales act as the food storage tissue. The tunic is a skin that covers the scales. The shoot is the developing leaves and flower of the bulb and the lateral buds develop into bulblets or subsets.
New bulbs form from the lateral buds underground, next to the originally planted bulb. After the bulb clumps form, usually after three to five years, they are mature. The clumps are dug up from the ground after any leaves have withered. The bulbs are gently pulled apart by hand then replanted immediately to grow new roots. Small bulbs may not develop for two to three years after planting, although larger bulbs may grow right away.
Corms, a variation of the true bulb, are also propagated using division. A corm develops on top of an old corm, with tiny cormels appearing around the large one. Dig up corms once the leaves wither on the plant. Remove the small cormels the corm before the large, new cormel is removed from the old. New corms are dusted with fungicide, suggests the Virginia Cooperative Extension, then put into a cool, dark place until planting time.
Lillies are propagated by the use of the scaling technique. Remove pieces of scale from the mature lilly bulb using a sharp knife is used to gently peel away a scale. Dust the scale with fungicide to prevent disease and place it with its base end down into a moistened growing medium such as perlite. Bulblets form at the base. After one to four years the bulblets are ready to plant.
Strict sanitary precautions should be followed during division. Wear gloves to prevent grease and oils from touching the bulb. Work in a clean, dust free environment and keep the bulb cool throughout the process. Do not allow the bulb to dry out at any time. Place the bulb into a cool, moist growing medium until it is needed.