Annual sunflowers bloom from summer into autumn. Depending on the variety, they can take 11-18 weeks to flower from seed sowing. With that in mind, it’s a good idea to sow sunflower seed every couple of weeks, so you’ll have a constant supply of cheerful sunflowers throughout summer.
Sunflowers are easy to grow from seed and are ideal for growing with children.They can grow to heights of up to two metres, bear impressive, long-lasting flowers, and look fantastic in gardens and allotments. They make an excellent cut flower.
Did you know? Sunflowers are related to Jerusalem artichokes, Helianthus tuberosus. If you plant Jerusalem artichokes and let them flower, they will bear beautiful, sunflower-like blooms.
How to grow sunflowers
To grow sunflowers you need a sunny, sheltered spot and a good soil – add plenty of well-rotted manure or garden compost before planting, if you can. Protect the young plants from slugs and snails and water your sunflowers regularly. You may also need to stake them if they’re in an exposed position.
Choose your variety carefully as some sunflowers will grow 50cm, while others grow over 3m. Sow seeds in pots from April and plant out when all risk of frost has passed. Prepare the soil well and add plenty of organic matter to the planting hole. Keep your sunflowers well watered and feed weekly to encourage them to grow tall. You may need to stake some of the taller varieties.
Sunflowers: jump links
- Where to grow sunflowers
- How to care for sunflowers
- How to propagate sunflowers
- Sunflower problem-solving
- Growing sunflowers: buying advice
- Types of sunflower to grow
More on growing sunflowers:
- How to plan for year-round colour
- Unusual sunflowers to grow
- Five-minute fun: Growing sunflowers with children
Find out all you ned to know about growing sunflowers, below.
Where to grow sunflowers
Sunflowers need sun. They do best in fertile soil in a sheltered spot, but will also do well in containers. However, if you want your sunflower to grow really tall, it’s best to plant it in the ground.
When to plant sunflower seeds
Sow sunflower seeds from April to May, individually in 10cm pots of peat-free, multi-purpose compost. Plant out into the garden when all risk of frost has passed, from early June.
How to plant sunflowers
Sow sunflower seeds into individual pots of peat-free, multi-purpose compost in April. Sow one seed per 7.5cm pot. Push the seed 1.5cm into the compost and water in. Cover pots with a clear plastic bag and place in a cool but bright place.
Watch Monty Don sow sunflower seed as part of his giant sunflower trial, in this clip from Gardeners’ World:
After the sunflowers have germinated, keep them well-watered until they’re ready to plant out at the end of May. Prepare soil by removing weeds and add plenty of organic matter. Plant the sunflowers at the same depth they were in the pot. Water well and stake plants with a bamboo cane or similar.
Here, Monty plants out his sunflowers and explains how to stake them:
Caring for sunflowers
Annual sunflowers need plenty of water. Feed them with 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.
Find out which sunflower fares best in Monty’s giant sunflower trial update:
How to propagate sunflowers
After flowering, sunflower heads develop masses of sunflower seed. You can harvest these to use in cooking, but bear in mind you will need to remove the tough seed coat before eating. Better still, take the seed and leave them to dry for a few days, before storing in a paper envelope in a dry spot, so you can sow them the following year. Make sure you leave some seeds for the birds, too.
Growing sunflowers: problem solving
Sunflowers are generally trouble free but young seedlings are susceptible to slug and snail damage. If you are only growing a few sunflowers, make sure you let them grow quite tall before planting out. You could also use wildlife-friendly slug pellets or copper tape to deter them.
Advice on buying sunflowers
- Choose from seeds, plug plants or young plants
- Bear in mind that some sunflowers grow very tall. Will they look out of place in your garden borders? Would a shorter variety be more appropriate?
- Check seed before sowing, making sure it’s free from mould
Where to buy sunflowers online
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 ‘Lemon Queen’ – a perennial sunflower, with lemon-yellow July to September flowers. Reaches 1.8m
- Helianthus giganteus – large single yellow blooms held on 2m long stems from June to August