Helianthus Shock-o-Lat

How to grow sunflowers

Find out how to grow, plant and care for helianthus, or sunflowers, in our expert Grow Guide.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Sow
Sow

Do not Sow in January

Do not Sow in February

Do Sow in March

Do Sow in April

Do Sow in May

Do not Sow in June

Do not Sow in July

Do not Sow in August

Do not Sow in September

Do not Sow in October

Do not Sow in November

Do not Sow in December

Plant
Plant

Do not Plant in January

Do not Plant in February

Do not Plant in March

Do Plant in April

Do Plant in May

Do Plant in June

Do not Plant in July

Do not Plant in August

Do not Plant in September

Do not Plant in October

Do not Plant in November

Do not Plant in December

Flowers
Flowers

Plant does not flower in January

Plant does not flower in February

Plant does not flower in March

Plant does not flower in April

Plant does not flower in May

Plant does flower in June

Plant does flower in July

Plant does flower in August

Plant does flower in September

Plant does not flower in October

Plant does not flower in November

Plant does not flower in December

Cut back
Cut back

Do not Cut back in January

Do not Cut back in February

Do not Cut back in March

Do not Cut back in April

Do not Cut back in May

Do not Cut back in June

Do not Cut back in July

Do not Cut back in August

Do not Cut back in September

Do Cut back in October

Do Cut back in November

Do not Cut back in December

Choose your sunflower variety carefully as some will grow 50cm, while others up and over 3m.
yellow-sunflower-2

Where to grow sunflowers

A sunny position is favoured – the annual flowers will always grow towards the sun. Annuals are happy to grow in pots of multi-purpose compost, whereas perennials prefer a border setting, planted in the ground. Avoid very small pots as plants will suffer if they are left to dry out.

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If planting annual types in garden soil they prefer a neutral or alkaline soil and one that is humus-rich and well-drained.

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Young sunflowers

Where to plant sunflowers

Annual sunflowers can be sown directly into their planting position as they’re hardy annuals. Sow in May in a weed-free soil and water well. If you miss the sowing time in April or May you will be able to buy potted plants in June.

Perennials plants can be quite enthusiastic growers, so ensure you give them plenty of space at the back or middle of a border. Feed with a general purpose fertiliser in spring.

sowing-sunflowers-in-tin-cans-2
Sunflower seedlings

Propagating sunflowers

Grow hardy annual types from seed by sowing directly into the garden in April or May.

If you would rather sow them into pots then plant one seed per 7.5cm pot. Push the seed 1.5cm into the multi-purpose compost and water in. Cover pots with a clear plastic bag and place them in a cool but bright place. Plant out young plants after the last frost. If you have any seed left over don’t be tempted to eat them – seed in packets may have been treated. Buy ones to nibble from the health food shop instead!

Perennial types are easily divided in autumn or spring. Simply dig out a section of a mature clump and pot on.

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Sunflower seedlings

Sunflowers: problem solving

Sunflowers are trouble free but young seedlings are susceptible to slug and snail damage. If you are only growing a few annual sunflowers try placing a copper garden band around each seedling. When the slugs meet the band they get what is similar to an electric shock.

sunflower-seedhead-2
Sunflower seedhead

Care

Annual sunflowers need plenty of water. They’re helped with a feed of tomato feed just before flowering. Don’t allow plants to dry out as very tall varieties will have a job to recover.

Very tall varieties may need the support of a garden cane – especially when growing in an exposed position.

After flowering leave the faded flower head intact so the birds can feast on the seeds. Once they have eaten their fill pull out the entire plant and put it on the compost heap.

Perennial types need very little care. Simply cut plants right down to ground level in autumn.

Leave the seeds for birds

The large seeds of the annual sunflower are adored by garden birds. Don’t deadhead plants. Allow the seed to ripen and be feasted on by our feathered friends. You could also use the seeds to make a pumpkin bird feeder.

Watering can
helianthus-lemon-queen-2
Helianthus ‘Lemon Queen’

Sunflowers to grow

  • Helianthus annuus ‘Russian Giant’ – this is a real cracking annual with flower stems reaching as high as 3m. A traditional yellow flower from July-September. A real race winner!
  • Helianthus annuus ‘Velvet Queen’ – coppery red flowers from July to September from this popular annual. Reaches 1.8m
  • Helianthus annuus ‘Teddy Bear’ – an annual with large pom-poms of double yellow flowers from July to September. Height 50cm
  • Helianthus giganteus – large single yellow blooms held on 2m long stems from June to August
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Discover more sunflower varieties to grow here