What is a Bulb?

Yellow tulips in bloom. (Photo credit: Karen Jeannette)

The general definition of a bulb is any plant that stores its complete life cycle in an underground storage structure. Types of underground storage structures that are classified under the term "bulb" include true bulbs, corms, rhizomes, tubers, and tuberous roots. Knowing the differences between each of these underground storage structures helps determine how to select, plant, and care for these bulbs.

For information and illustrations of different types of bulbs, see:

• Bulb Basics (University of Illinois Extension), part of the University of Illinois' Bulbs and More, provides a look at each type of underground storage structure.

Selecting Bulbs by Region

Crocus, a spring-flowering bulb, in bloom. (Photo credit: Mary Meyer)

Selecting bulbs that are appropriate for your region is made simple by visiting:

• Bulb.com (International Flower Bulb Center).

-User hint: Click on the "Public" link, then "Bulb Basics," and finally "US planting regions." Click on your planting region to get regional bulb information, including when to plant and what kinds of bulbs are best suited to your area.

Planting and Maintenance

Spring flowering bulbs are planted in fall (Photo credit: Mary Meyer)

The following sites provide information about planting and maintaining bulbs. The first three sites are geared toward gardeners whose regions are well suited for growing common spring bulbs. "Bulbs for Florida" takes a look at growing bulbs in a warmer region, where cold treatments for many common bulbs such as tulips, hyacinth, and even some lilies are inadequate or absent, due to warm winter temperatures.

See:

• Fall-planted Bulbs and Corms (Colorado State University Extension). Find instructions on site selection, planting, and growing bulbs. The bulb planting chart is especially helpful in visualizing how deep to plant the bulbs.

• Spring-Planted Bulbs, Corms, and Roots (Colorado State University Extension). This article covers site selection, purchasing, and soil preparation. The culture of some of the most popular specific bulbs is provided, too.

What happens to your bulbs if unseasonably warm temperatures cause your spring flowering bulbs to pop up early?

• Find out in this discussion: Warm Weather Brings Up Bulbs (Purdue University Extension).

• Bulbs for Florida (University of Florida Extension). Learn about growing bulbs in this warm region, including specific details as to which bulbs are well adapted to Florida and which are not.

Fertilizing and Nutrition

Bonemeal is an organic source of phosphorus and is best applied at planting time if a soil test indicates phosphorus is needed. (Photo credit: Karen Jeannette)

When is the best time to fertilize bulbs?

See:

• Bulbs Fertilizing (Colorado State University Extension)

Bulbs get hungry, too! Hungry for light.

See:

• Clean Up Bulbs to Encourage Next Year's Blooms(Purdue University Extension) discusses the importance of keeping the foliage on bulbs after flowering.

Forcing and Storing Bulbs

Forcing bulbs is one way to enjoy bulbs indoors at different times of the year, not just when outdoor conditions permit. Storing bulbs is a practice that permits a gardener to dig up bulbs and bulblike plants that would otherwise not overwinter in the ground and replant again the following growing season.

The following articles provide insight on what, when, why, and how you can force or store bulbs.

See:

• Forcing Bulbs for Indoor Beauty (University of Minnesota Extension). This offers instructions for forcing bulbs.

Should you save the potted tulips you bought at the supermarket and replant for future blooms?

• Saving Forced Bulbs (Colorado State University) discusses the effort needed to get forced bulbs to bloom successfully and eventually.

Tender bulbs are bulbs that will be killed by the cold and will not survive winters if not brought indoors.

For more information, see:

• Storing Tender Bulbs and Bulblike Structures (University of Minnesota Extension). This useful publication for storing tender bulbs includes a chart with detailed storage information for a number of popular tender bulbs.

Dahlias in bloom. (Photo credit: Mary Meyer)