Sitting in the garden last week I heard a sudden sound behind my ear, a delicate buzzy knocking that continued for a few seconds, stopped, and then started again before lapsing into silence.

I knew without looking that it was a bumble bee visiting the last of the foxgloves, its whole body, I could imagine, hunched into a purple flower like a bear in the mouth of a cave.

Where would a garden be without bees? Unpollinated to some degree, of course. Fewer apples, fewer rose hips.

But there is also an aesthetic pleasure in watching bees and butterflies at work, just as much as there is in watching house martins build a mud nest or a bat swoop around the garden at dusk; it’s seeing beauty at work.

Everyone knows bees are becoming scarce — look at the price of a jar of local heather honey if you want to see it in pounds and pence — but at least in gardens we can do something to boost their numbers.

You could start by planting heather. No, not a moor’s worth, but a patch of half a dozen of our native, summer-flowering Calluna vulgaris, planted now.

You’ll need a lime-free soil of course, or a raised bed of acid compost. Just the thing for a sandstone rockery.

People write to me to ask how to get rid of white clover in a lawn because it sticks up and — yes — it brings in bees that might be trodden on with bare feet. Well, here’s an idea for you: have some longer grass but cut to 10-12cm where the clover can flower away.

On the bear-in-a-cave principle you can plant penstemons now. They share the foxglove’s pouch-shaped flowers and are also tempting to the bees. Slimmer bees, at least. And they will go on flowering and providing colour until the end of the season.

Bees love honeysuckle and everyone should have some somewhere. To avoid mildew, remember head in the sun, feet in the cool.

Bees are too busy to worry about clever colour schemes and so the occasional less-than-spectacular flower is fine by them. Fennel, for instance, throwing up its green or bronze feathery pillars, topped by a cow-parsley plateaux of flowers on which the bees can land, helipad fashion. Teasels are excellent too. Bees come first, to feast on the mauve cones of flowers, followed by seed-eating birds in winter.

And for the butterflies? Well, buddleia of course. It’s not strictly the time to be planting shrubs, but in the case of buddleia where the colour is strong — purples and blue-pinks — it’s not a bad idea to plant it while you can see the colour properly. Glorious Verbena bonariensis, a serious weed in some parts of the world, makes the perfect mauve eyrie for butterflies, and if you plant it now it will also self seed usefully into cracks and crannies, even if the plant you buy fails to make it through to next winter (pot-grown ones often don’t because of too-soggy peat compost).

In a hot spot beside the house you ought to plant a pot of 2-3 dark blue heliotropes (Heliotropium arborescens). Some smell more than others, some are pale and others dark, but butterflies seem to enjoy them all. Maybe they feel safe on the cauliflower-shaped head?

Plausible nonsense, I’m sure, but still in autumn they absolutely queue up to land on the mounded pink heads of the ice plant Sedum spectabile.

You can plant that now too, or better still scrounge some. Slice away a fork of root and shorten the stem to 6-7cm and it will be fine.

Butterflies enjoy the daisy family too, and there are a few that they especially love. Helenium is a medium-sized perennial, flowering now until the autumn. The dear old pot marigold, Calendula officinalis, is another, a half-hardy annual grown from seed sown either in autumn or spring. Michaelmas daisies are another. But all these flowers are best for the insects if you plant single-flowered varieties that have the minimum of petals and maximum nectar. The many-petalled doubles contain less nectar, and diving through all that fluff is not as productive for the poor butterfly.

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