When to plant and prune Sunflower (annual)
Helianthus annuus
No pruning or deadheading; leave the seedheads standing in autumn for finches to feed on.
Planting, flowering and pruning by region
Pruning is driven by dormancy rather than frost, so it is not shifted by region — the same cut is right in Inverness and in Penzance. Planting windows do move.
| Where you are | Plant | In flower |
|---|---|---|
| South West Coast and Cornwall | mid April to late May | early July to mid September |
| South Coast and Channel | mid April to late May | early July to mid September |
| Greater London (Urban Heat Island) | mid April to late May | early July to mid September |
| South East and Home Counties | mid April to late May | early July to mid September |
| East Anglia | mid April to late May | early July to mid September |
| Midlands and Lowland Wales | mid April to late May | early July to mid September |
| Wales and West Coast | mid April to late May | early July to mid September |
| Northern England | mid April to late May | early July to mid September |
| Scotland Lowlands and Central Belt | mid April to late May | early July to mid September |
| Scotland Highlands and Islands | mid April to late May | early July to mid September |
| Northern Ireland | mid April to late May | early July to mid September |
| Channel Islands and Isle of Man | mid April to late May | early July to mid September |
How to prune it
No pruning or deadheading; leave the seedheads standing in autumn for finches to feed on.
Severity: none.
Feeding
A potassium-rich liquid feed every couple of weeks helps container-grown sunflowers; plants in decent ground rarely need feeding.
At a glance
- Type
- Annual
- Hardiness
- H3
- Eventual height
- 2.5 m
- Eventual spread
- 0.6 m
- Years to maturity
- 1
- Spacing
- 45 cm
- Sun
- Full sun
- Soil
- Any reasonably fertile, well-drained soil in full sun and shelter from strong wind
- Evergreen
- No
- Pollinator value
- 5 out of 5
- Grows in a container
- Yes, 20 litres or more
- Difficulty
- Easy
Growing notes
Annual sunflowers last just one year - they flower, set seed and die, so save or buy fresh seed each spring. Sow indoors in pots from late March or outdoors in mid-April and May; young plants are extremely vulnerable to slugs and snails. Cultivars range from 30cm dwarfs to 3m or more, and most annual sunflowers need a strong bamboo cane put in at planting time, with the stem tied in as it grows (giants are best tied to a wall or fence). Do not cut the plants down as soon as they finish - leave the seedheads for chaffinches, greenfinches and goldfinches.
What usually goes wrong
- slugs and snails destroying seedlings
- wind snap on tall unsupported stems
- birds taking sown seed
- powdery mildew late in the season
- top-heavy plants in containers
Related guides
Cross-checked against RHS guidance.