Bulbs in the Florida Garden
Florida's warm climate allows gardeners to choose from a wide variety of plant bulbs. With proper care, these plants will thrive and produce beautiful flowers year after year.
What Is a Bulb?
Bulbs are thick underground storage organs that help plants survive tough weather conditions, such as drought or cold. Bulbs are usually the plants' reproductive organs as well.
Not all bulbous plants have true bulbs. Others have corms, tubers, tuberous roots, or rhizomes. In this article the terms "bulb" and "bulbous plants" will refer to all bulbous plants, not just true bulbs.
Choosing a Bulb
Florida's climate lets growers raise a variety of tropical and subtropical bulbs in their garden for bedding plants or cut flowers. However, common northern species such as tulips, hyacinths, and some lilies do not do well this far south.
The types and varieties listed below are bulbs that do well in Florida.
Kaffir Lily (Clivia)
Marcia (Walking Iris)
Moraea (African Lily)
Shell Lily (Shell Ginger)
The Planting Site
Sunlight & Shade
Most bulbs thrive in a sunny location, but some (such as caladiums) do best in partial shade. Avoid planting bulbs in heavily shaded areas to prevent thin, spindly growth and poor flowering and foliage color.
Bulbs require well-drained soil, so bed preparation is important. If the site does not drain properly, build raised beds filled with soil that has good drainage. You can also improve soil drainage by installing drainage tiles or digging ditches to carry water to lower ground.
Soil & Fertilizer
Till and amend the soil by adding a 3- to 4-inch layer of organic matter (such as peat, compost, or well-rotted manure) and 1 to 1 ½ pounds of 12-4-8 fertilizer or an equivalent amount of other complete fertilizers per 100 square feet of bed.
Particular bulbous plants may require additional soil preparation. For more information, contact your county Extension office.
Once you have prepared the site, you can plant the bulbs. The amount of space between bulbs will vary with the species and the effect you want to create.
Spacing and depth recommendations are similar for many bulbous plants, but some may require more room than others. Dig holes with a trowel or small shovel, and place bulbs in the holes with the points facing up. Then firm soil around and over the bulbs, and water them.
In order to have healthy plants and beautiful flowers, follow these general care recommendations :
- Control weeds through mulching.
- Fertilize with a complete fertilizer (12-4-8) once or twice during the growing season.
- Keep the soil around the bulbs moderately moist at all times (except when you are drying off bulbs at the end of the season).
- Remove dead blooms before they produce seeds. Seed set will reduce flowering the next season.
Digging & Replanting
Many bulbs grow best if left in the ground year after year. Others may become crowded and bloom poorly. Digging them up and replanting will promote regular flowering and larger flowers.
Tropical bulbous plants in North Florida should be dug and stored to prevent injury from cold winter temperatures.
After digging up bulbs, store them for a few days in a dry, well-ventilated place away from the sun. Remove the roots, dead leaves, and soil, and place the clean bulbs in a single layer in trays to store them.
Bulbous plants are easily propagated vegetatively.
True bulbs develop bulblets (miniature bulbs). Once the bulblets are full-size, they are called offsets. Separate the offsets from the original bulb and use them as additional plantings.
The number of growing seasons required for the offsets to reach flowering size will vary with the kind of bulb and the size of the offset.
Corms produce new corms on top of the old corms. Miniature corms (called cormels) are produced between the old and new corms. Cormels can be separated from the mother corms and stored along with the new corms over winter for planting in the spring.
New corms usually produce flowers the first season, but cormels require two to three years of growth to reach flowering size.
Tubers, tuberous roots, and rhizomes are propagated by cutting them into sections that contain at least one bud each.
Bulbous plants will also produce seed that will grow into flowering plants. This method of propagation is not recommended, however, since many varieties today are hybrids. Flower color and type may be highly variable in seeded plants, and results cannot be predicted.
Diseases & Pests
Bulbous plants are susceptible to damage by many diseases and pests.
Insect-transmitted viruses are difficult to control. Symptoms of virus infection include stunted growth, mottled or striped leaves, and malformed foliage and flowers. The only treatment for viruses is to destroy infected plants and to control insect hosts.
Rotting Bulbs & Roots
Poor drainage can promote the growth of soilborne bacteria and fungi and lead to bulb rot. Once the pathogen has invaded the root zone, little can be done to control the disease. Increase the soil drainage and remove all infected plants to keep the disease from spreading to healthy plants.
Chlorosis (yellowing of foliage) is a common symptom caused by lack of nitrogen, iron, zinc, magnesium or manganese. Chlorosis may be caused by an actual nutritional deficiency in the soil, or the roots may be unable to absorb these nutrients because of poor aeration, disease, or nematodes.
Your local Extension office can help you determine the cause of foliage chlorosis.
Insects directly damage bulb plants and allow disease organisms into plant tissue. Bulbous plants are susceptible to chewing insects, aphids, thrips, spider mites, mealybugs, and nematodes.
If pest infestations are severe or large numbers of plants are involved, chemical control may be needed. For recommendations on pesticide selection and application, as well as non-chemical control options, contact your county Extension office.
Moles, pocket gophers, rabbits, and squirrels can all damage bulbs and bulb-like structures. Contact your county Extension office to learn about the best control methods for wildlife damage.
For more detailed information on the best bulbs to plant in your area, how to grow bulbs, pest management, and other questions, contact your local Extension agent.
Adapted and excerpted from:
R. Black, et al, Bulbs for Florida (CIR552), Florida Cooperative Extension Service (Archived).