Why Sunflowers Are a Gift to Garden Birds

A single sunflower head can hold hundreds of seeds, and those seeds are exactly the kind of high-energy food that finches, tits and sparrows need to see them through autumn and winter. Grow the right variety and you effectively plant a bird feeder that refills itself, no cleaning, no refilling, no metal perches required. Better still, the flowers themselves are a magnet for bees and hoverflies in summer, and the thick stems and leaves offer shelter for beetles, spiders and other small invertebrates that birds will pick off later.

If you garden on a balcony, a small courtyard or a narrow strip beside a path, you might assume sunflowers are off the menu. They are not. You simply need to choose compact cultivars and treat them well. Here is how to get a proper crop of seed heads from even the smallest space.

Choosing Compact Varieties for Pots and Tubs

Standard sunflowers can reach two metres or more, which is hopeless in a window box but fine at the back of a border. For containers, look for dwarf and semi-dwarf types that top out somewhere between 60cm and 120cm. These tend to have sturdy stems that do not need staking in a sheltered spot, and they still produce generous heads.

• Dwarf branching types are the best value for birds because each plant produces several smaller heads rather than one big one, which means a longer supply of seeds and more flowers over the season.
• Single-flowered varieties are what you want. Double or "fluffy" sunflowers may look splendid, but many have little or no seed, and the pollen is often inaccessible to insects.
• Red and mahogany tones work well in pots and are just as attractive to pollinators, though birds seem to find the seeds every bit as tempting.

If you have a sunny windowsill and nothing else, a single dwarf sunflower in a two-litre pot will still deliver a seed head worth leaving standing. Two or three pots grouped together look better and give birds a proper little feeding station.

Sowing and Growing in Tight Spaces

Sunflowers are not fussy, but they are greedy and thirsty. Fill your pot with a good peat-free multipurpose compost and mix in a handful of slow-release fertiliser, or plan to feed fortnightly with a tomato-type liquid feed once buds appear. Choose the largest pot you can accommodate: a 10-litre container is far better than a 5-litre one because it holds moisture and stops the plant toppling in a gust.

Sow seeds from late April onwards, two seeds per pot about 2cm deep, and thin to the strongest seedling once they are a few centimetres tall. Keep them somewhere bright and frost-free until the risk of late frost has passed, then harden them off gradually over a week. From late May they can go outside.

• Water deeply and less often rather than little and often. Sunflowers resent drying out and will sulk, producing small heads.
• Shelter from strong wind. A south-facing wall is ideal, but keep pots out of the fiercest gusts or the stems will snap just as the heads fill.
• Succession sow a few seeds every three weeks until early June. This staggers flowering, so you are not left with one frantic week of seed and then nothing.

Making the Most of the Flowers While They Last

Let the flowers open fully and leave them alone. This is the moment when the garden earns its keep: bees, bumblebees and hoverflies will work the heads for weeks, and the insects they attract become food for hungry nestlings nearby. If you are growing in a small garden, position pots where you can see them from a window, because you will want to watch the traffic.

Try not to deadhead. It is tempting to tidy up, but a fading sunflower is doing valuable work. The petals drop, the head nods, and the seeds begin to swell and ripen. This process takes roughly four to six weeks after flowering ends, depending on the weather.

Leaving the Heads Standing for Winter

This is the single most important step, and the one most often skipped. Once the back of the head turns from green to yellow-brown and the seeds feel plump when you rub them, the crop is nearly ready. Resist cutting it down. Leave the stems standing right through autumn and into winter.

• Goldfinches are the classic visitors, clinging acrobatically to the head and picking seeds out one by one. A small group can strip a head in a couple of days.
• Greenfinches, chaffinches, siskins and house sparrows will all take advantage, along with the occasional great tit or coal tit.
• Insects overwintering in the hollow stems add another layer of value, and a frosty sunflower head looks rather beautiful with a bird balanced on top of it.

If the weather turns very wet, heads can rot and the seeds go mouldy. In a small garden you can simply bend the stem over and tuck the head under a nearby shrub, or cut it and wedge it into a fork in a branch. Either way, the birds will find it.

A Few Practical Pointers

Slugs and snails will nibble young seedlings, so protect them for the first few weeks with a barrier of grit or a cloche. Squirrels and mice may raid ripening heads, which is frustrating but rarely total. If you have space for several plants, you will always have some left over.

When spring comes and the head is finally bare, do not be too quick to pull the stem. Cut it down to about 20cm and leave the stubby remains in the pot or border until late spring, giving any overwintering insects a chance to emerge. Then compost it and start again.

For very little effort and a scrap of sunny space, sunflowers deliver twice: once in summer, bright and busy with pollinators, and again in the colder months, when a goldfinch on a nodding seed head is one of the finest sights a small garden can offer.