Most gladioli reach 90-120cm in height with some reaching even higher, and their sword-like foliage adds interest even before the blooms arrive. They begin flowering around 80–100 days after planting. In Scotland, this means planting in April or May for blooms from late July through September. The flowers come in almost every shade imaginable from pure white to saturated crimson and deep purple, as well as pastel shades of coral, peach, and lavender, and there are even varieties which are bi-coloured.
Gladioli thrive in a sunny, sheltered spot with well-drained, fertile soil. In colder areas or exposed plots, a south-facing wall or raised bed offers extra warmth and protection. In wetter gardens, they can be grown in large pots with added grit to ensure good drainage.
Gladioli are also brilliant for cutting to enjoy indoors. It is best to harvest the stems when the lowest two or three flowers have opened and the rest are still in bud and they’ll continue to open in the vase bringing dramatic vertical interest to floral arrangements. Cut the stems early in the morning and plunge straight into water to maintain freshness.
‘Green Star’ – unusual lime-green flowers on tall, sturdy stems
‘Peter Pears’ – a classic coral-orange colour which is long-lasting in the vase
‘Purple Flora’ – a bold, rich purple bloom for late-season impact
‘Prins Claus’ – white blooms delicately flecked with pink
‘Flevo Laguna’ – a compact, dwarf variety ideal for exposed sites or for growing in containers
Succession plant for longer blooming: stagger corm plantings every two weeks from April to early June to extend flowering into late summer.
Plant deeply and stake gently but firmly: set corms 10-15cm deep and about 10cm apart. As soon as the shoots are 15-20cm tall, insert thin canes or pea sticks beside each plant and tie loosely with soft string or twine. In more exposed areas, a grid of twine supported by perimeter canes can help keep groups of gladioli upright without damaging stems.
Feed for finer flowers: keep soil moist but not waterlogged. Regular watering once the buds appear will encourage larger, longer-lasting blooms. Gladioli are hungry feeders so apply a high-potash liquid fertiliser, like a tomato feed, every 10-14 days once the flower spikes begin to form. Avoid high-nitrogen fertilisers, which can lead to lush foliage but fewer blooms.
Deadhead to channel energy: remove spent flowers promptly to encourage the plant to direct energy back to the corm rather than seed production to benefit next year’s blooms.
Lift or protect over winter: in colder areas of the country, lift corms in autumn after the foliage dies back and store in a frost-free, dry place. Let them dry fully, remove loose husks and old roots, then store in paper bags or trays. In milder areas, mulch deeply and hope for mild weather.