When to plant Gladiolus?

Gladioli are tender summer-flowering corms that thrive in full sun and well-drained soil. In temperate European gardens, plant corms from late March through May, once the risk of hard frost has passed and soil temperature reaches at least 10°C. Choose a sheltered spot in full sun with loam or sandy soil that drains freely—waterlogged conditions will rot the corms. Prepare the planting area by digging over the soil to a spade's depth and incorporating well-rotted compost or grit if drainage is poor. Plant corms 10–15 cm deep (roughly three times their own height) with the pointed growing tip facing upwards. Space them 15 cm apart in groups or rows for the best visual impact. Deeper planting helps anchor the tall flower spikes and reduces the need for staking. For a succession of blooms throughout summer and into early autumn, plant batches of corms at two-week intervals from late March to early June. This staggered approach extends the flowering season considerably. Immediately after planting, water the area lightly to settle the soil around the corms, but avoid saturating it. In exposed or windy gardens, consider placing supports such as bamboo canes or linking stakes alongside the planting row early on, before the foliage emerges. Tall varieties reaching 100–120 cm will almost certainly need staking as the heavy flower spikes develop. Apply a 5 cm layer of mulch around emerging shoots in late spring to suppress weeds and retain moisture, keeping the mulch clear of the stems themselves to prevent rot.