Q.: My gladiolus quit blooming after a few years. What can I do differently?
A.: When you find that your bulb-type plants just don’t keep coming back like the rest of your perennials, the best thing you can do is to understand that these plants are often treated as annuals in Georgia. Some gardeners pull the bulbs at the end of the season and purchase new healthy mature stock the next spring, and some gardeners lift, store over winter, and replant their own favorite bulbs the following year.
Either is fine. If you like to change up your garden color theme each year, these plants are inexpensive enough to start afresh in spring with a whole new variety.
Gladiolus is sometimes called “Sword Lily,” the name coming from Latin. It is the diminutive of gladius, or sword. Looking at the shape of the leaves, you can see it is well named. Gladiolus is genus of the Iridaceae or Iris family, which also wield the long sword-shaped leaf.
“Glads” have a type of bulbous root called a corm. It’s not actually a bulb, rather a thickened section of the main stem, with papery layers. On the corm grow buds of the future leaves. Here’s where your problem with repeat blooming comes in. If you are leaving your Gladiolus corms in the ground over winter from year to year, the corms may be getting crowded in their soil, and simply don’t have the strength to force leaves and blooms up out of the crowded earth.
According to Walter Reeves, the best thing you can do for the vigor and health of your Gladiolus is to lift or dig them up each October, cutting the stalks to within an inch of the corm. Lay them aside in an airy space and let the soil dry around the roots for a week or two. After carefully knocking off the soil, inspect the large corms for damage or desiccated areas, and discard those corms.
Remove the smaller cormels around the main body and set those aside to plant in the spring near the larger corm. Store the larger and smaller corms by size in mesh bags or in boxes lined with dry peat moss, and leave in a well-ventilated area (about 50 degrees) for the winter. The larger corms will bloom the next summer, but it will take a year or two for the small cormels to grow large enough to flower.
As soon as the soil is warm enough to work in the spring, go ahead and plant the corms about four inches deep in a sunny, well-drained spot in the garden. Between the large corms, intersperse the smaller cormels about three inches apart to mature for the summer and prepare themselves for the following year’s blooms. Gladioli are moisture-loving plants, but are not bog plants. Give them plenty of water throughout the summer, but the soil must have good drainage. If your soil is heavy clay, you may just want to turn an amendment such as compost into the bed before planting the bulbs. The compost will lighten up the soil some, let air in, and let water drain away from the bulbs.
Mulch the plants well, using 2 to 4 inches of shredded mulch, pine straw or mini nuggets to keep weeds down and moisture in the soil. Gladioli are unhappy when they must compete with weeds for nutrients, so keep the bed well weeded. Take care not to cultivate too deeply near the roots when weeding, so not to damage new root growth (thus delaying bloom time). Planting time is a good time to go ahead and install support stakes near each large corm. Gladiolus is so top-heavy that a good head of blossoms will cause the entire plant to flop over onto the ground. As they get taller, just tie them up loosely to the stake for support.
Gladiolus is such a lovely flower that the work involved twice a year is really not a thankless chore. It’s all in knowing that a bit of tender loving care will help these beauties thrive in your garden from one year to the next.