A true bulb is a plant that stores its entire life cycle in an underground structure. There are several types of these underground structures besides true bulbs. There are corms, tubers, tuberous roots and rhizomes. These structures store water and other nutrients to ensure a plant's survival. Each type has different characteristics, but only certain ones are referred to as true bulbs.
Kinds of Bulbs
There are two types of true bulbs: turnicate and imbricate. Turnicate bulbs have a paper-like wrap around to them protect them from drying out or damage. These types of bulbs include tulips, hyacinth or daffodils.
The imbricate bulb does not have the protective wrap. These types of bulbs must remain moist until planting to prevent any damage. A good example of an imbricate bulb is the lily.
True bulbs are comprised of five main parts. The first part is the basal plate or the bottom from where the root grows. The second main part is the fleshy scales where the primary tissue is going to develop. The third part is the tunic--the protective covering for the fleshy scales. The fourth part is the shoot that emerges with the flower and leaves. Finally, there are the lateral buds, which later will develop into shoots or offsets.
Planting bulbs requires some thought before starting. Bulbs can be planted alone in mass plantings in a garden, but once they are done blooming the space will be empty for the rest of the season. Bulbs can also be worked in around other plants so that as they fade other plants will hide the yellowing leaves of the bulb flower.
In addition, good soil preparation is a must for bulb beds. Good soil is well-drained and amended according to the type of soil in the garden. Clay soil needs compost and peat moss added to help with drainage. The added materials should be tilled in 12 to 18 inches deep. pH balance is important too, as flowering bulbs need a pH of 6 to 7.
Planting depth depends on the size of the bulbs. The holes should be 1 ½ to 2 times the size of the bulb. Bulb fertilizer is recommended to help feed the bulbs. A thin layer of dirt should cover the fertilizer before the bulbs are planted pointed end up. Freshly planted bulbs should be watered thoroughly.
Bulb planting is also seasonal. Certain flowers that bloom in the spring are planted in the fall; crocus, tulips, and hyacinths. Other bulbs can be planted in the spring and will grow and flower in the summer. For example: different kinds of lilies and dahlias.
Digging and Separating Bulbs
Once the flower blooms and fades, the bulb goes dormant. Before digging up or separating bulbs, wait until dormancy. Separating can be done if a plant needs to be relocated in a garden, but is also beneficial to the plant. Plants can become overcrowded and this will cause poor blooming later on. It also removes diseased or dead bulbs and revitalizes the bulb bed.
In United States Department of Agriculture (USDA) hardiness zones where winters are too cold, some bulbs need to be dug up and stored for the winter. In fall before the first hard frost the bulbs should be dug up and the loose dirt shook off. Certain bulbs can even be rinsed, but not cannas or dahlias. Bulbs can be stored in paper or mesh bags and hung in cool dry places. Temperatures should be about 55 degrees Fahrenheit.