The sunflower is one of the nation’s best-loved flowers. Although most sunflower varieties have yellow flowers, you can grow varieties with rusty red, green and even white flowers.
Annual sunflowers bloom from summer to autumn. Depending on the variety, they take 11-18 weeks to flower from seed. 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 blooms throughout summer.
Sunflowers are easy to grow from seed and are ideal for growing with children.They can grow to heights of up to 2m, 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
Growing sunflowers from seed is easy, you just need a sunny, sheltered spot and good soil – add plenty of well-rotted manure or garden compost before planting to enrich your soil, if you can. Protect the young plants from slugs and snails and water regularly. You may also need to stake them if they’re in an exposed position.
Choose your variety carefully as dwarf sunflowers grow to just 50cm, while taller varieties reach up to 3m in height. Sow seeds in pots from April and plant out when all risk of frost has passed. Water frequently and if growing for height – feed weekly with a nitrogen-rich fertiliser 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
Where to grow sunflowers
Sunflowers need sun. For best results grow your sunflowers in a rich, fertile soil in a sheltered, sunny spot. Sunflowers grow well in pots but if you’re growing for height it’s best to grow them in the ground.
When to plant sunflower seeds
The best time to plant sunflower seeds is between April and May. Sow seeds individually in 10cm pots of peat-free, multi-purpose compost. Cover pots with a clear plastic bag and place them in a sunny, warm spot for the best chances of germination. Remove the plastic cover once the seedlings have emerged. You may need to protect them from slugs and snails.
How to plant sunflowers
If you suffer with slugs and snails you may benefit from potting your sunflowers on into larger pots of fresh compost, before planting out. This means the plants will be bigger when planted into their final growing positions, and therefore more resilient to slugs and snails. Regardless of how big they are when you plant them, make sure you don’t plant them out until all risk of frost has passed, usually from June onwards.
Watch Monty Don sow sunflower seed as part of his giant sunflower trial, in this clip from Gardeners’ World:
When planting out, prepare soil by removing weeds and add plenty of organic matter such as compost or well-rotted manure. Plant the sunflowers at the same depth they were in the pot. Water well and stake taller varieties with a bamboo cane or similar.
Here, Monty plants out his sunflowers and explains how to stake them:
Growing sunflowers in pots
Sunflowers do well in pots although they usually don’t grow as tall as those growing in the ground. Sunflower plants are heavy feeders so make sure you water the pots regularly (daily in hot weather) and feed fortnightly with a nitrogen-rich fertiliser, switching to a high potash fertilise, like a tomato feed, when the plants begin to bloom.
To grow sunflowers in pots, sow the seeds in small pots as you would normally in spring, and then transplant them individually into larger pots when they’re large enough to handle, eventually potting them on into a 30cm pot of loam-based, peat-free compost, ideally with added organic matter. Stake taller varieties as you would for plants growing in the ground.
Where to buy sunflowers online
Caring for sunflowers
Annual sunflowers need plenty of water and will suffer if allowed to dry out. If you’re growing for height, feed fortnightly with a nitrogen-rich fertiliser and then switch to a potash-rich tomato feed just before flowering.
Stake tall varieties with a sturdy cane to prevent wind rock, especially if 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, remove the seeds from the seedhead 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 suffer with slugs and snails, avoid planting sunflowers until they are big enough to withstand being attacked. If growing sunflowers in a greenhouse or cold frame then regularly inspecting and removing slugs and snails can be effective. You may also consider using wildlife-friendly slug pellets or copper tape to keep slugs and snails at bay.
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
Sunflower ‘Russian Giant’
‘Russian Giant’ is a huge annual sunflower, bearing a single flower as high as 3m. This traditional yellow-flowered variety blooms from July-September.
Height x Spread: 3m x 30cm
Sunflower ‘Shock-o-lat’ F1
This red-flowered sunflower bears large flower heads with a red-brown central boss that yields edible sunflower seeds, and bronze-red petals with yellow tips. The stems have a purple tinge, which contrasts well with the green of the leaves.
Hx S: 2m x 30cm
Helianthus ‘Lemon Queen’
This perennial sunflower bears masses of small, lemon-yellow blooms from July to September, and comes back year after year.
H x S: 2m x 45cm
Sunflower ‘Choco Sun’
One of the best dwarf sunflowers to grow, ‘Choco Sun’ is fast growing and bears masses of large yellow flowerheads. It’s a perfect sunflower for pots and is fun for children to grow.
H x S: 34m x 35cm
Frequently asked question about growing sunflowers
How long do sunflowers take to grow?
Sunflowers are fast growers and can reach a height of 2m or more in just three months. Bear in mind that their growth rate and eventual height depend on factors like variety, availability of food and water, and weather conditions, so you’re not always guaranteed the heights predicted on your seed packet. For best results, grow your sunflowers in rich soil in open ground, in a sunny, sheltered spot, and water and feed frequently.
Are sunflowers perennial?
Sunflowers can be annual or perennial. The tall, often stingle-stemmed varieties we grow in our gardens tend to be annual sunflowers, while perennial sunflowers tend to be known by their botanical name Helianthus, and include the lovely variety ‘Lemon Queen’.
When do sunflowers bloom?
Sunflowers bloom from summer into autumn, typically around July to September. The flowering time of your sunflower can depend on several factors, including when you sowed the seed, weather conditions and availability of food and water.
from BBC Gardeners World Magazine https://ift.tt/GEbzxFS
