Unlike hardy bulbs such as Tulips and Daffodils tender bulbs are able to survive in only the mildest parts of United States. While this need for warmth will vary depending upon the type of bulb their ability to withstand colder temperatures is usually limited to USDA garden zones 8, 9 and 10. These tropical bulbs must be dug up in the fall and stored over the winter if they are to be planted again in the next growing season. While this sounds like a lot of work the extra effort is worth it as these are some of the most unique and beautiful flowers a gardener can grow and with a little bit knowledge you can grow them too!
Although tropical flowers are often referred to as bulbs this term is used to describe a variety of tropical plants including tubers, rhizomes and corms as well as bulbs. What they have in common is that they grow underground and during the growing season they build up nutrients which give them the ability to survive a period of dormancy before they can begin their growing cycle all over again. Cold weather brings on this dormant period and warmer weather initiates growth again. Examples of these tropical plants include Cannas, Caladiums, Dahlias, Gladiolus and certain types of Begonias.
Tropical bulbs are planted after all danger of frost in your area is past. This date will vary depending upon your USDA Zone but can be anywhere from Mid-March through Late-May. These bulbs can be planted directly in the ground, at a depth that will vary depending upon the bulb you are working with. Some bulbs, such as Caladiums, can be planted in areas that get more shade than sun while others such as Dahlias and Gladiolus grow best in places that get full sun all day long. Most of the bulbs require soil that is moist but that does not allow water to pool and they do best when but on a regular fertilizing schedule such as every 2 weeks if grown in containers and monthly if planted in a flower bed.
The fact that you must plant them after your last frost date means that tender bulbs will flower in the middle to late summer into the fall. While you wait for these blooms to appear many of these plants have colorful and attractive foliage which should be left in place until the first frost which will generally damage or kill the foliage. Once this occurs it is time to dig up the bulb, remove any foliage that remains and allow the bulb to dry out for a few weeks prior to storage for the winter. You must be sure to remove the bulb before the ground freezes or it will die.
After the bulb is dried out it can be put in a container such as a box that is lined with a material such as peat moss or even shredded paper and then placed in a cool, dry place such as a basement room or in the garage. You should check the bulbs during the winter to make sure they don’t get “fuzzy” because they are too moist or start to shrivel because they are too dry. Now that you know about tender bulbs why not give them a try?