By Matthew Biggs

Published: Wednesday, 15 June 2022 at 12:00 am

---

The wild sunflower Helianthus annuus, one of 70 species in the genus, is found in any sunny, dry open place, often as a weed in cultivated fields of North America, from the Mississippi and Pacific Coast, south to Mexico and beyond.

Growing up to 4.5m tall it has rough, coarsely toothed, leaves and large, flat, ‘daisy’ flowers in branched clusters atop stiff, green stems.

Cultivated by North American Indians as early as 3000BC for oil, medicine and textile dyes, they were introduced to Europe by the Spanish around 1500. By the 18th century, they were popular in gardens and by 1769 were being developed extensively for cooking oil production, particularly in Russia.

Commercial breeding focussed on producing sturdy, single-stemmed giants with seed-filled heads. Even today, varieties such as Helianthus annuus ‘Russian Giant’ remain unrivalled for height – the tallest on record was 7.5m tall with flowerheads over 30cm in diameter.

Modern varieties tend to look more like wild species: they are shorter, usually slender-stemmed, with branching flowerheads displaying many smaller flowers with variation in the size of the petals and central boss. The palette has diversified from traditional yellow to a host of multicoloured beauties, combining sophisticated hues with simple flowers, many of them pollen-free, blooming over many weeks and lasting well as cut flowers.

They range from dwarf, pollen-free Helianthus annuus ‘Munchkin’, reaching 60cm, its large, green-tinted centre fringed with attractive pale yellow petals, and ideal in pots or at the front of borders, to the imposing Helianthus annuus ‘Taiyo’ – raised in Japan, with robust stems reaching more than 3m, and boasting imposing, single flowers up to 30cm across, with deep orange-yellow petals and a rich chocolate-brown centre.

As they were an inspiration in art, so they are in gardens. Sunflowers may not be the most sophisticated garden plants, but their robust nature and blooms beaming with good-natured, bucolic honesty, make them worthy of a place in any garden – it’s impossible not to respond with a smile.

How to grow sunflowers

Where to grow sunflowers

Sunflowers are most successful in an open sunny site on moist, free-draining soil. Growth can be increased by placing them against a sunny wall.

Modern cultivars of sunflower are ideal for filling gaps in borders, grouped among mixed shrub borders, grown alongside informal bedding displays or even in cottage gardens.

Taller varieties make very good temporary screens and are striking grown in graded ranks, with the tallest at the back of a border as transient vibrant colour.

Smaller varieties can be grown in containers and it is worth remembering when placing plants, that the buds follow the sun from east to west but once open, they usually face east.

Caring for sunflowers

Improve the soil by forking in well-rotted organic matter beforehand if necessary. Keep them well watered throughout the growing season, stake tall varieties growing in windy locations, particularly those with large flowers.

How to direct sow sunflowers

Sow seed when soil is warm (usually from mid-April) at 5cm deep, with 30cm between rows for small varieties and 45cm for large varieties. Cover seeds with wire mesh to protect them from birds and squirrels. Keep the soil moist and feed tall varieties with a half-strength solution of general liquid fertiliser once they reach a height of 60cm. Make a second sowing two weeks later to extend the flowering season. Plants grow better when sown directly – transplanting tends to check growth and make plants less floriferous.

How to start sunflowers in pots

Sow seeds singly from March onwards, at a depth of 2.5mm in 7.5cm pots of seed or multipurpose compost. Water thoroughly then cover the pots with clingfilm, place in a clear polythene bag or cover with bubble wrap.

Alternatively, place the pots on a warm windowsill or in a propagator at 13°C (55°F). Remove the cover when the first leaves appear. Harden them off in a sheltered position before transplanting outdoors once frost is no longer a danger.

Cutting sunflowers

Set aside a part of the garden for growing as cut flowers: blooms can then be harvested without spoiling an ornamental display.

Plant the seeds 20cm apart and, once established, feed with high potash fertiliser to encourage flower production. Sow every fortnight for six weeks from April onwards for continuous production; in hot summers, allow 60 days from sowing to blooming.

Pick flowers early in the day, when the dew has dried. Remove leaves so that just two or three remain near the bloom, then place in a bucket of water, leaving them to stand for several hours in a cool room before placing in a vase. Change the water every few days.

The best sunflowers to grow

Helianthus annuus ‘Pastiche’

Helianthus annuus ‘Pastiche’ is packed with blooms, around 12.5cm in diameter, in a diverse blend of ‘sunset’ shades. At 1.5m, they are ideal for adding height and structure to borders.

Helianthus annuus ‘Russian giant’

Ascending effortlessly to 3m or more, the large, yellow face and bright petals of this famous old variety make for a guaranteed prize-winner at the village show.

Helianthus annuus ‘Munchkin’

This little chap reaches just 60cm tall and is the first pollen-free sunflower for growing as a pot plant. Ideal at the front of a border, it is also a great novelty plant for children.

Helianthus annuus ‘Sundown’

‘Sundown’ is a manageable 1.8m tall, with pleasing chestnut and yellow contrasting tones. It becomes almost single-stemmed when planted densely.

Helianthus annuus ‘Taiyo’

Tall but perfectly formed and topped by a huge single flower up to 30cm across, ‘Taiyo’ is excellent when planted in regimented ranks as a temporary screen.

Helianthus annuus ‘Magic roundabout’

With its sharply contrasting colours, ‘Magic Roundabout’ is one of the most stylish sunflowers of all. Reaching 2.4m, it is an ideal backcloth for ornamental borders.

Helianthus annuus ‘Orange mahogany’

The striking diffusion of colour from the central boss is a particularly pleasing trait of this cultivar. Grows to 1.5m in height.

Helianthus annuus ‘Vanilla ice’

© Jason Ingram

A serene, elegant plant, with delicate chocolate brown centres and ice-cream yellow petals, carefully disguising its ‘sunflower’ genes. 1.5m tall.

Helianthus annuus ‘Bicentenary’

© Jason Ingram

With its outstanding flowering period and deep chestnut eyeliner on contrasting yellow petals, ‘Bicentenary’ is well worthy of its status on the RHS anniversary list. 1.8m tall.

Helianthus annuus ‘Black magic’

The colour of ‘Black Magic’ makes it one of the most spectacular sunflowers of all. Planted in a large group, they add an aura of mystery to beds and borders. Grows to 1.8m.

Helianthus annuus ‘Music box’

These perky little faces create a feast of eye-catching colour. Bushy and free-blooming, they are ideal for front gardens, for the world to join in and enjoy. Just 80cm tall.

Helianthus annuus ‘Claret’

Free-flowering ‘Claret’ is a dramatic sunflower with shiny black discs and deep-coloured petals. A reliable specimen, it keeps its colour, even in the heat of summer. Up to 1.8m.

Helianthus annuus ‘Velvet queen’

‘Velvet Queen’ proudly displays 15cm diameter blooms on well-branched stems around 1.5m tall. They come in a range of shades but are often a rich, brick red in colour.

Helianthus annuus ‘Sparky’

© Jason Ingram

This distinctive variety, is worth growing for the unusual quilled, forward-facing petals carried the length of the stem over many weeks during the summer. 1.5m tall.

Helianthus annuus ‘Earthwalker’

© Jason Ingram

The tall stems of ‘Earthwalker’, can reach 2-3m and are ideal for displaying its earthy blooms to their best effect. This is very much a ‘designer’ sunflower.

---