Don’t leave gladiolus out of your garden plans for this summer. One season of growing them will let you understand why gladiolus are a top favorite with so many people. Gladiolus bulbs are also called “corms”, which is their correct botanical classification. The corm is a shortened and thickened section of the stem that appears at the base of the plant. It is solid and is covered with dry husks-really the base of old leaves. They’re called tunics. On the corm are buds for each layer of leaves. Gladiolus require much the same growing condition as most vegetables and garden flowers. They like lots of sun, and a fertile, well-drained soil. Although they can be grown successfully in almost any type of soil, you’ll get best results in sandy loam. They don’t like to compete with tree and shrub roots, nor do they grow their best crowded up against a foundation. If you plant in such places, be sure to supply extra food and water.
Before planting, dig complete plant food into the bed, about 4 pounds for each 100 feet of row. Plant food used later in the summer should be watered in immediately after applying to let it get to the roots at once.
Plant glads as early in the spring as the soil is fit to work (about two weeks before the last expected spring frost). Set bulbs 6 inches deep in light soil, 4 inches deep if soil is heavy. Fill the hole only half full when making the first spring planting to let bulbs get extra warmth from the sun, and fill rest of hole after growth starts. Large bulbs should be about 7 inches apart. The blooming season can be stretched by making succession plantings, by planting bulbs of several sizes, and by using varieties which take different lengths of time to mature.
Start shallow hoeing when first leaves come through the ground. Glads suffer when forced to compete with weeds. Eliminate weeds early in the season. The new corm and the new roots are formed on top of the old one during the growing season; deep cultivation too near the roots breaks off the new roots and slows up growth.
The worst insect enemy is the gladiolus thrip, a very tiny, black, winged insect. It sucks the juice from the plant, and leaves a silvery appearance at first and then causing them to turn brown. Thrips also cause deformed flowers and prevent flower spikes from opening at all.
Thrips on bulbs should be killed before planting. In the garden, start dusting or spraying with insecticide when leaves are six inches tall. Apply once a week (oftener if rain comes) right through flowering time.
Water is very important! In fact, it’s usually the greatest single factor in the success of full gladiolus growing. Rain seldom supplies enough moisture so make sure the bed gets an inch of water every week. Start watering when there are five leaves on the plants.
Tall varieties will probably need staking to prevent the flower spike from flopping over in the wind. Hilling the soil will help, but staking individual flower spikes or creating a grid with stakes and string are the best ways to keep flower stalks upright.
Cut the flower spikes ordinarily when only one or two flowers are open. The rest will open in water indoors. Cut spikes cleanly and at a slant. Put the spikes in water at once. Laying them down for any length of time will make the tips take on a permanent curve.
Leave at least five leaves on the plant since it must continue growth to mature the bulbs for next year.
Keep weeds under control even after the blooming period is over. However, you can let up on watering except in very dry weather. Thrip control can also be relaxed unless there is a serious infestation.
Digging time for the bulbs depends on the planting date. Lift them, a spading fork will do, when growth has stopped but before foliage turns brown, usually 4 to 6 weeks after blooming. Cut off the tops just above the corm, and store in an open box to let them cure for a month. You can make your own shallow screen-bottom tray containers for storing them; the screen allows circulation of air through the corms. Deep containers like bushel baskets keep them too hot and confined, and they aren’t recommended. After the corms have cured, clean them by removing the dried up roots at the base of the new corm, and break off the dried old corm. Leave the husks on the new one unless there is danger of thrip infestation.