If you pay attention to the essential points regarding care, location and wintering, you can get the attractive gladioli to bloom every year. However, the perennial flowering plant from the iris family is not winter-proof as it originally comes from regions where there are no ground frosts.
Are gladioli perennial and how do you overwinter them?
Gladiolus are perennial plants that are not winter-hardy. In order to get them to bloom every year, their bulbs must be protected from frost over the winter: shorten the plants, dig up the bulbs, let them dry out, store them frost-free and replant them in spring.
Onions overwinter protected
If you simply leave the tubers in the ground in autumn, the heat-loving gladiolus will freeze and therefore will no longer germinate next year. When the first night frosts threaten, you have to shorten the gladioli to around ten centimeters and dig them up. Be very careful when doing this, as the fine membranes surrounding the onions must not be damaged.
Take a close look at the perennial bulbs, because only solid flower bulbs without external damage are he althy. Discard soft, rotten, or pest-infested bulbs immediately to avoid infecting other bulbs.
Storage in winter quarters
Carefully remove the coarsest soil and allow the gladiolus bulbs to dry out a little. For this purpose, the onions are layered in a wooden box lined with newspaper (€44.00 on Amazon) and placed in a frost-free but cool room.
So that the perennial onions sprout quickly next year, you should check them several times in the first few days for pest infestation. You can then overwinter the bulbs covered with a sand-soil mixture.
Planting gladiolus bulbs
As soon as the outside temperature is above freezing at night, the gladioli are placed in the bed. If you want particularly early flowering plants, you can plant the bulbs in a flower pot filled with soil for a few weeks beforehand. If you delay planting the bulbs over a few weeks, you can extend the flowering season from summer into October.
Tip
If you want the gladiolus bulb to produce long flower blades every year, it is important not to cut too many flowers. This weakens the plant even if you leave some leaves standing. The gladiolus needs flowers and foliage to store nutrients in the bulb.