When to plant and prune Gladiolus
Gladiolus flowers from late May to early September and the dates below cover planting, flowering and the pruning window.
Planting, flowering and pruning by region
Gladiolus is frost-tender, so its timings shift across the UK. Plot works them out from the Midlands and Lowland Wales baseline using Met Office average frost dates.
| Where you are | Plant | In flower | Prune |
|---|---|---|---|
| South West Coast and Cornwall | mid March to late April | late May to early September | late May to early September |
| South Coast and Channel | late March to early May | late May to early September | late May to early September |
| Greater London (Urban Heat Island) | mid March to late April | late May to early September | late May to early September |
| South East and Home Counties | early April to mid May | late May to early September | late May to early September |
| East Anglia | mid April to late May | late May to early September | late May to early September |
| Midlands and Lowland Wales | mid April to late May | late May to early September | late May to early September |
| Wales and West Coast | early April to mid May | late May to early September | late May to early September |
| Northern England | late April to early June | late May to early September | late May to early September |
| Scotland Lowlands and Central Belt | early May to mid June | late May to early September | late May to early September |
| Scotland Highlands and Islands | late May to early July | late May to early September | late May to early September |
| Northern Ireland | mid April to late May | late May to early September | late May to early September |
| Channel Islands and Isle of Man | early March to mid April | late May to early September | late May to early September |
Growing notes
Depth: plant corms 10-15cm deep - the RHS rule of thumb is the depth of three corms stacked on top of each other - and space them roughly the same distance apart as they are deep. Planting can start in mid-April even though the last frost may not have passed, because the shoots only emerge once the danger of frost is over; flowering follows from the end of May and June onwards. Tall large-flowered types need staking or a sheltered spot.
At a glance
- Spacing
- 12 cm between plants
- Eventual height
- 100 cm
- Eventual spread
- 15 cm
- Hardiness
- H3
- Sun
- Full
- Frost tender
- Yes
- Grows in a container
- Yes, 15 litres or more
- Balcony rating
- 3 out of 5
Feeding
General fertiliser raked in at planting, then a tomato-type (high-potassium) feed once the flower spikes start to emerge.
Pruning group
Cut spikes for the vase or remove faded spikes; leave the leaves standing to feed the new corm
Winter protection
Garden hybrids that are not fully hardy should be lifted in late summer/early autumn, about six weeks after flowering and before the foliage fades: cut the leaves to a short stub, dry the corms in a warm airy place for a few weeks, then store them in trays somewhere cool and frost-free indoors. Only on light, free-draining soils in warm counties can they be risked in the ground over an average winter.
What usually goes wrong
- gladiolus thrips
- gladiolus corm rot / dry rot
- aphids and virus
- wind snap on tall spikes
- slugs on young shoots
Related guides
Timings cross-checked against RHS guidance for gladiolus.