Why sunflowers earn their place in a wildlife garden

Few plants give so much back for so little effort. A sunflower sown on a windowsill in April will be several feet tall by July, feeding bumblebees, honeybees and hoverflies from its wide, pollen-laden face for weeks. Come September, those same flowers turn into heavy, nodding seed heads that goldfinches, greenfinches, house sparrows and even the odd great tit will strip bare. You get height, colour and structure in the border in summer, and a free bird feeder on a stalk in autumn. There aren't many annuals that pull off both tricks.

They are also forgiving. Sunflowers will tolerate poor soil, a bit of neglect and a windy position (with a little help), which makes them ideal for new gardeners, school plots and the scruffy end of the garden where nothing else quite works. The main thing is to choose the right varieties, because not all of them are useful to wildlife.

Pick open, pollen-rich flowers rather than showy doubles

The sunflower has been bred hard for the cut-flower trade, and some of that breeding has been at the expense of insects. Pollen-free varieties and heavily doubled forms with dozens of petals look magnificent in a vase but offer bees almost nothing, as the centre is hidden or sterile. As a rule, go for single-flowered types with a broad, chocolate-brown disc in the middle. That disc is the engine room — hundreds of tiny florets packed with pollen and nectar.

• Tall classics: 'Russian Giant' and 'Mongolian Giant' reach 2.5–3m with huge, open heads. Brilliant for a sunny wall or the back of a border, but they will need staking.
• Coloured singles: 'Velvet Queen', 'Evening Sun' and 'Red Sun' are single-flowered with rich mahogany and rust tones, and bees work them just as keenly as the yellow ones.
• Small-space options: dwarf and semi-dwarf varieties will still flower and set seed in a large pot on a patio, though the heads are naturally smaller.
• Ones to think twice about: pollen-free F1 cut-flower types, and fluffy doubles such as 'Teddy Bear'. Pretty, but close to useless for pollinators.

Sowing and growing: the practical bits

Sow indoors in small pots from mid-April, or direct where they are to flower from late April to mid-May, once the soil has warmed and the last hard frosts have passed. Push each seed about 2cm deep, pointed end down if you can manage it, and allow 45cm between tall varieties and 30cm for shorter ones. Sunflowers resent root disturbance, so if you raise them in pots, plant them out young and keep the rootball intact.

Slugs are the biggest threat early on. A ring of grit, a night patrol with a torch, or raising plants in tall pots before planting out will usually see them through. Choose the sunniest spot you have — they will lean and sulk in shade. Tall varieties in exposed gardens benefit from a stout cane and a soft tie, and a little general-purpose feed once the buds appear will repay you with bigger heads.

Succession sowing for a longer feed

One sowing gives you a glorious few weeks, then a gap. Sow a second batch three or four weeks after the first and you will have flowers right into early October — valuable for late bumblebees and honeybees still stocking up before winter. A third sowing in June in a warm, sheltered spot often works in southern gardens, though the plants will be shorter and the heads smaller.

If you'd rather not fuss, simply let a few heads stand through the winter. Sunflower seed is generous with self-seeding, and you will often find seedlings popping up the following spring where the birds dropped a snack.

Leave the seed heads standing — the autumn pay-off

This is the part most gardeners get wrong. As soon as the yellow petals drop and the back of the head begins to turn from green to brown, the seeds underneath are ripening. Resist the urge to cut the stems for tidiness. Leave them standing and watch what happens: goldfinches will cling to the nodding heads and pick out the seeds with neat, deliberate flicks, often in small chattering flocks. Greenfinches, chaffinches, sparrows and tits will join in. The hollow stems are also used by overwintering insects.

If you want to save some seed for the bird table later in winter, cut a head once the seeds are plump and dark-striped, with the back of the head fully brown. Tie it in a paper bag and hang it somewhere dry and airy for a fortnight, then rub the seeds free and store them in a cool, dry jar. Thread a few heads onto garden twine and hang them from a branch or a washing line in January, when natural food is scarcest and the birds are hungriest.

Either way, you get a second season of wildlife from a single packet of seed — first the bees in August, then the finches in November. That is a very good return for a few square feet of sunny border.