One of the features of bulbs that make them so attractive is the ability for the gardener to divide their bulb plants to produce new growth, share with friends, or just plant in different areas of the landscape.
In addition, many bulb flowers become overgrown, and reducing the growth through dividing bulbs is the best way to get things back under control. It is generally easy to tell when a planting of bulbs needs to be divided. One sure sign is when a previously well blooming planting of bulbs has begun to provide only sparse blooms. Most times the culprit is overcrowding, and the solution is to divide those bulbs. Properly dividing the bulbs will reduce the overcrowding and allow the remaining bulbs to bloom for vibrantly.
The techniques used to divide bulbs depend on the exact type of bulb to be divided. There are actually five different types of bulb flowers – true bulbs, corms, tubers, rhizomes and tuberous roots. The techniques for dividing each type of bulb vary, so it is important to know which type you are working with. Any good gardening guide will tell you which type of bulb you have, and that information is usually provided when you buy the bulbs as well.
To divide a true bulb, you should begin by carefully separating the original bulb from the smaller bulb growing at its base. When dividing lily bulbs, you should be careful to first remove the outer scales from the basal plate. After the outer scales are removed, the ends of the bulb should be dipped in a rooting hormone, and the bulb should be planted immediately.
Corms are not true bulbs, and they renew their growth each season through the production of a new corm, and sometimes also small cormels growing on top of the original corm. To divide corms, the gardener should simply separate the healthy new corms, as well as any cormels, from the original corms.
As tubers mature, they increase both their size and the number of growing points. However, most tubers do not form distinct increases. Therefore, to divide tubers, a large tuber should be cut into two or more sections, being sure that each section contains at least one growing point.
The new growth on rhizomes is produced from growth points located at their sides. Rhizomes are divided by breaking the sections apart at the natural divisions between them, being sure that each of the new divisions has at least one growth point on it.
A tuberous root will contain several growing points. Some, like daylilies, form separate and distinct plants, which can simply be pulled apart. This type of sectioning is generally done in fall or summer while the plant is still in its growth stage. Other tuberous root plants, such as dahlias, are more difficult to separate. In order to separate more difficult plants like dahlias, you will need to cut the clumps apart so that each root has a growth bud from which to start. With these types of plants, it is best to separate them in early spring, before planting.