Gladiolus needs drainage and space for developing flower spikes. Choose the container around the variety's expected height rather than the corm size alone.
Plant corms for the local season
Gladioli grow from corms, not layered true bulbs. Follow the variety's planting guidance and local frost conditions. Choose useful sun and drainage, with room for the mature flower spike.
Support before the spike leans
Tall varieties may need discreet support in an exposed position. Put it in carefully to avoid damaging underground growth. A container should be substantial enough to hold roots and remain stable.
Keep leaves after the flowers
Water active roots when needed and use appropriate feed where indicated. Cut spent spikes without removing all healthy leaves; the foliage helps replenish the new corm. Do not stop care immediately after taking flowers for a vase.
Overwinter according to the type
Hardiness differs, and tender varieties may need lifting and frost-free storage where winters are cold. Let material mature appropriately, keep labels and inspect stored corms. Discard clearly deteriorated pieces rather than planting an unchecked batch together in the next season.
Related reading
Gladiolus Types: Flower Spikes and Plant Names