Spring Flowering Bulbs:
Why Don't They Bloom?
Spring-flowering bulbs are among our most beloved plants, signifying the end of winter with their brightly colored blossoms. Although relatively easy to grow, they can prove reluctant to re-bloom in subsequent years. This frustrating condition may be caused by lack of light or poor nutrition.
The inflorescence that a bulb sends up in spring is formed the previous summer shortly before the foliage dies down. After flowering, the plants manufacture food through sunlight hitting their leaves. Whether a bulb flowers is closely related to the amount of food manufactured the previous year.
To bloom well, most bulbs need at least a half-day of direct sun. Some bulbs, such as tulips or daffodils, do better with even more. Early flowering genera such as Crocus, Galanthus, and Scilla can flower well when situated under trees because they complete their growth cycle before the trees leaf out. Because foliage is part of the plant's food-manufacturing mechanism, it is important that it not be braided or removed until it yellows.
If bulbs are receiving sufficient light but still not flowering well, poor nutrition could be the cause. Although most bulbs are not heavy feeders, they can benefit from a light application of a balanced fertilizer in early spring.
By John B. Morse,
Curator of Outdoor Gardens