How to grow Sunflower in New Zealand
Sunflowers are the giants of the summer garden, with big golden, bronze or lemon flowers that are magnets for bees and other pollinators. They grow fast from seed sown where they are to flower, in full sun and warm soil. Grow giants for fun, branching types for cutting, or dwarf types for pots, and save the seed heads for the birds or for roasting.
📖 Our full guide: How to Grow Sunflower in New Zealand
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| Northland | September to December | |
| Auckland | September to December | |
| Waikato & Bay of Plenty | October to December | Sow from October, once the inland frosts are over in late September. Warm coastal Bay of Plenty gardens can start a few weeks earlier under cover. |
| Central North Island | November and December | |
| Wellington & Lower North Island | October to December | |
| Nelson & Marlborough | October to December | |
| Canterbury | November and December | |
| Otago & Southland | November and December | |
| Central Otago | December |
Not to be confused with: Sunflower microgreens, which are young seedlings of the same plant grown on a tray for eating, and Jerusalem artichoke, a perennial sunflower grown for its tubers.
Where to plant
Sunflowers want full sun and some protection from strong winds, in free-draining soil enriched with compost or sheep pellets. They are best sown in the warmer months. Tall types make useful summer shade for heat-sensitive crops on their shady side.
- Northland and Auckland: sow from September once the soil warms.
- Waikato and the Bay of Plenty: sow from October, once the inland frosts are over.
- Wellington and Nelson: sow from October to December.
- Central North Island, Canterbury, Otago and Southland: sow in November and December; in Central Otago, in December.
Choosing a variety
- Giant single-stemmed types are grown for height and huge heads; stake them in windy spots.
- Branching types such as Bronze Shades give many smaller flowers over a longer season, excellent for cutting.
- Dwarf types such as Dwarf Sensation suit pots and borders.
- Pollen-free cut flower types are bred for vases and do not drop pollen.
How to plant
- Sow seeds where they are to grow, about 2 cm deep, as sunflowers dislike root disturbance. Cover, firm down and water well.
- Keep the soil moist while the seeds germinate.
- Thin seedlings to about 50 cm apart for large types.
- When seedlings are about 5 cm tall, mulch around them with bark or pea straw.
Watering and feeding
Water regularly, especially once flower buds form; deep watering encourages deep roots that keep tall plants upright. Sunflowers are not heavy feeders; a little compost at sowing is plenty.
Pruning and care through the year
- Stake tall varieties in windy spots before they get top heavy.
- Protect seedlings from slugs and snails, which can wipe out a sowing overnight.
- Pick cut flowers just as the petals begin to open, early in the morning.
Harvesting
For seed, wait until the back of the head turns yellow-brown and the seeds are plump, then cut the head with a length of stem and hang it somewhere dry and airy, covered with a paper bag to catch the seed. Rub the dry seed out. Or leave heads on the plant for birds to feed on in autumn.
Growing in pots
Dwarf sunflowers grow well in pots of container mix in full sun. Sow directly into the pot, keep moist while germinating, and water regularly.
Companion planting
Sunflowers bring in bees and helpful insects, and tall types can give summer shade.
Good companions
- Cucumber Can scramble up sturdy sunflower stems and benefits from the bees they attract.
- Sweet Corn Shares the tall back row of a summer bed.
- Tomato Benefits from the pollinators and helpful insects sunflowers attract.
Keep apart
Avoid planting these close to sunflower.
- Potato Both are hungry, and tall sunflowers shade the potato bed.
Pests and diseases
Slugs and snails on seedlings are the biggest threat. Mature plants have few problems.
Pests to watch for
- Slugs and snails (slugs and snails) Seedlings eaten off at ground level overnight.
- Aphids Clusters of small insects on stems and under flower heads.
- Caterpillars Holes in the leaves and chewed flower heads.
- Birds Seed stripped from ripening heads.
Diseases to watch for
- Downy mildew Yellow patches on leaves with white growth beneath, and stunted plants.
- Botrytis Grey mould on the back of flower heads in wet weather.
Common questions
When should I plant sunflowers in New Zealand?
In the warmer months, once the soil has warmed and frosts are over: from September in the north and November or December in the south.
Should I sow sunflowers in pots first?
It is best to sow them where they are to grow, as they dislike root disturbance. If you start them in pots, transplant them young.
Why do sunflowers face the sun?
Young sunflowers turn to follow the sun across the sky during the day, a habit called heliotropism. Mature flower heads usually settle facing east.
How do I harvest sunflower seeds?
When the back of the head turns yellow-brown and the seeds are plump, cut the head and hang it somewhere dry with a paper bag over it. Rub out the dry seed.
Are sunflowers good for bees?
Yes. Each flower head produces a large amount of pollen and nectar, which draws bees and other pollinators to the garden.
Sources we checked: Yates NZ: How to grow sunflower; Kings Plant Barn: Sunflowers grow well guide; Kings Seeds: Sunflower range.