Digging up your gladioli corms is a chore that some gardeners may be able to avoid. This is entirely dependent, however, on your local environment and climate type. A misjudgement and a desire to avoid extra effort might result in your gladioli plants not coming up in the spring. Armed with the correct information, you will be able to make a decision that will best suit your plants.
When You Can Leave Gladioli in the Ground
If you live in a zone where mild winters are the rule, you will be perfectly safe leaving your gladioli in the ground. This is especially the case when your gladioli appear to be healthy and thriving. A good rule of thumb is that if you do not have any chance of hard frost in your area, you may leave a gladiolus plant in the ground. In terms of USDA hardiness zones, the cut-off point at which you can safely winter gladioli in the ground is Zone 7.
When You Should Dig Up Your Gladiolus Corms
In places where winters are severe enough to cause death or damage to your gladiolus corms, it is mandatory that you dig them up and store them for the winter. Before you store them, you must allow the gladiolus corms to "cure," or dry out, for approximately two weeks so that they will become dormant and keep well for the entire cold season. Also, if you happen to have any gladiolus plants in your garden that are infected with disease, pests or fungus, you should dig them up and dispose of them before they can infect any other plants.
Advantages of Digging up Your Gladiolus Corms
Even if your climate permits leaving gladiolus corms in the ground, you may want to dig them up and store them for the winter nonetheless. By removing the gladioli for the winter, you will be able to inspect all the corms and make certain none of them are infected by root rot or another fungal disease. If one or more corms do happen to be infected, this allows you to remove the infected corms before they have the chance to spread the disease to the rest of your gladioli. This will also give you an excellent opportunity to sort old and young gladioli corms.
Advantages of Leaving Your Gladioli in the Ground
If your climate permits, there are a few advantages to leaving gladioli in the ground. First, you save yourself the effort of digging up and storing the corms. In addition, the gladioli will not have to undergo any replanting stress, and the root systems will remain well-established. You will also avoid the possibility of a mishap in storage, such as the corms getting wet and possibly decayed or infected.