Gardening: Oh, save me from the doldrums of August: Anna Pavord has the summertime blues. Flowers are flagging, the ground too dry, the mistakes too obvious

The second half of the summer in my garden is never as good as the first. Partly, I suspect, it is a question of attitude. The combination of a bronze-leaved rodgersia with mounds of spurge and francoa is actually better now than it was two months ago, because the francoa is flowering, with long, elegant, pink spikes. But I have got used to it. From mid-May to mid-July I could not pass this group without stopping to admire the lustrous sheen of the rodgersia. Now I stump up the bank just saying 'oh yeah, that'.

You greet spring and early summer with an enormous head of steam built up during the too-idle winter. You long for the garden show to be back on the road. You are out on your hands and knees in January looking for the first signs of aconites and snowdrops. You are filled with a glorious optimism. You tell yourself that this season will be the most delirious yet in the garden.

In August there are still treats to come, but I am not on my hands and knees looking for them. I badly need the cyclamen along the front of the winter border of hellebores, which has been without incident for too long. Yet I do not think I will be dragging in the first passer-by to look at them, the way I feel like doing earlier on in the season when the tulips or the first flush of the 'Buff Beauty' rose come out.

Part of the problem is August itself. It is a limbo month; a month in which, for most of our lives, we have been somewhere else. We are not used to anything important happening in August. September is back-to-school time.

By then I will have taken the garden by the scruff of the neck again. I shall be ordering bulbs, gathering up the filthy scraps of paper from the pockets of my favourite jackets and transcribing the cryptic scrawls into nurserymen's orders.

But what about now? It is too hot to labour. The ground is too dry. The green of the beech has turned heavy and sullen. Too many plants are looking secondhand. I did make a conscious effort this year to bring on fresh troops in August and, poor things, they are doing their best. The 'Goldilocks' rudbeckias raised from seed (Suttons, pounds 1.25) are coming into full flower now (rich brown-gold with bold, dark centres), but in most places their companions are too obviously flagging. The rudbeckias are like people turning up past midnight at a party where the other guests are beginning to wilt.

The only place they really work for me is in the dead ground around four handsome Helleborus foetidus. These are at their peak between March and May, but the plants have a naturally good shape and the evergreen foliage, though sombre, is always handsome. The golden rudbeckias give them just the right summer fillip and the group is given an extra boost because behind is a big clump of a particularly dotty Shasta daisy called 'Shaggy'. Each petal looks as if it has long forgotten whatever it was that it set out to do. So much like the garden's own fallible custodian.

If I lived in Scotland or the North of England, I am sure I would feel differently about the August garden. Things get going so much later up there: in August you cannot indulge, as I am now, in an unforgivable ennui about the garden. You have to grab the summer and make the most of it before the ground locks up again. And Scotland has long been geared to an August season: people go there to kill things this month and they like to have a herbaceous border to look at after their shooting.

I do not think I am alone, though, in thinking my garden better in the first half of summer. If you look at the National Gardens Scheme yellow book, you will find the feeling reflected in the times that people choose to open their gardens. The ones who need to make money from them, of course, have to open all the time, but the others open their gardens on days earlier rather than later in the year. In Berkshire, for instance, there are 28 open days until 10 July; nine afterwards. In Essex you get the same pattern: 52 open days up to the July watershed; 11 after.

Partly, of course, it is the way things creep up on you through June and July that makes August such an unsatisfactory month for gardeners. The bindweed, that has been sneaking around perniciously underneath currant bushes and roses, now begins to haul its great bulk on top of your treasures and flaunt its supremacy with its great white flowers, each one a metaphoric 'Yah boo sucks'.

The artemisia 'Powis Castle', you suddenly notice, is infested with blackfly. Slugs have finally succeeded in shredding the hostas. The gamble you took, that the crocosmia 'Lucifer' would be able to hold itself together without a stake, did not come off. The violas run out because you never kept up with the deadheading.

Another part of the dissatisfaction comes from the fact that by this time of the year you know what did not work in the garden but you cannot yet do anything about it. It is the wrong time to be moving plants; the wrong time to be planting new ones. Everything is in suspense. I have to go on looking at the oriental poppy that is much too near the peony, though I have at least sheared down the poppy's leaves to keep them out of the peony's way.

I have also dug up half the acanthus, not to move it but to ditch it. This is partly because the wretched thing got mildew, which it never used to do, and partly because it had crept from its original position, mid-border, much too far towards the front. I say confidently that I have 'dug up' the acanthus but it is difficult to get rid of it. The bits of root you missed bob up again, smiling brightly. That is a characteristic of many plants propagated from root cuttings. Each bit of chopped underground root thinks it is doing you a favour by sprouting.

So what is the answer to the August problem? I need to think more carefully about where I am putting the summer boosters, as I have discovered with the rudbeckias. The everlasting statice 'Azure' (Thompson & Morgan, pounds 1.19) that I raised from seed would have looked better planted in big blocks between the feathery artemisias in the front border than it does standing by itself among collapsed oriental poppies.

The picture on the seed packet of this statice showed a clear, strong, blue flower. In fact it has a single white flower on each spray of blue, which gives a quite different effect. I rather like it, but it is not the flower described in the catalogue.

I could grow cannas and sunflowers to make me feel more positive about this month. I could brighten up the place with more fuchsias and geraniums. I could increase the proportion of annuals in the garden, for they are in full swing in August. Or I could return to the habit of a lifetime and just go away.