A Spring-flowering Bulb's Growth Cycle
When a bulb arrives in fall, ready to be planted, it is easy to think of it as dormant until spring, when visible growth starts. However, root growth starts as soon as the bulb is placed in the ground. The optimal time to plant is during the fall, when soil temperatures approach 55 degrees F.
After planting in the fall a bulb immediately sends out roots. In most cases top growth will remain safely underground until spring.
The changes a bulb undergoes from the time it is planted in the fall until it goes dormant in summer is known as its growth cycle. While there are some variations, the growth cycyle for most spring-flowering bulbs is on the whole quite similar. The illustration at right shows what happens under, as well as above, ground during the growth cycle of a tulip.
In the spring, after they have flowered, the bulbs will start to reproduce themselves, usually by some process of division. To do this successfully the bulb needs to be able to build up fresh strength, and this is the reason why the foliage should never be cut before it has ripened. When you dig up a tulip bulb in early summer you will not find the large bulb you planted in the fall. Instead there will be a clump of two or more medium-sized bulbs plus a large number of tiny baby bulbs, or offsets. These offsets will not be able to produce a flower.
