Bulb flowers, often the first harbinger of spring, bring bright blooms to the garden long before anything else is growing. Many bulbs, such as daffodils, need dividing every few years in order to continue producing healthy flowers. While midsummer to fall is the best time to divide bulbs, if you are moving the garden bed or having trouble getting the bulbs to thrive earlier digging and separation may be necessary.
When to Divide
Spring bulbs flower in late winter or early spring. Once the flower dies off, the leaves remain green and on the plant for six weeks to three months to replenish the nutrients in the bulb for next year's blooming period. Removing the foliage during this time might inhibit the bulbs blooming ability because there is no way for it to gain its nutrients. The earliest to dig bulbs without any chance for damage is six weeks after the flowers fade, or in late spring and early summer. Digging them sooner could kill the bulbs, which won't be apparent until the following year. If you must dig sooner, try to leave as much of the roots and foliage in place when you replant to give the bulb the best chance for survival.
Dividing the Bulbs
Cut back the foliage before separating the bulbs if it has already begun to yellow. Otherwise, leave green foliage in place. Dig a 6- to 8-inch-deep trench around the bulbs then slide your trowel under them. Lift them out of the ground and brush off any excess soil. Examine the bulbs for signs of damage, such as soft spots that indicate rot or shriveled bulbs that indicate disease. Dispose of the damaged bulbs. Twist apart bulbs where they join together until they separate. The larger the bulb, the more likely it is to survive and produce healthy flowers, so discard smaller bulbs unless you have a large planting bed you wish to fill in.
Replanting the Bulbs
Replant separated bulbs as soon after digging as possible, especially if you dug them up before the foliage and roots began to die. Plant spring bulbs in full-sun garden beds that are well drained. Overly wet beds lead to bulb rot. Working compost and bulb fertilizer into the bed before planting aids both drainage and soil nutrition. Plant bulbs to a depth equal to three times their width. Water them thoroughly after planting so they have instant access to water and the nutrients in the soil.