The last hurrah

Jo Arnell explains how to squeeze in as much colour as possible before the inevitable onset of the chill...

It's autumn. I'll spare you the poetry, cut to the chase, seize the (ever shortening) day, and head out to the garden. There are lots of good reasons to be outside now - before the bad weather sets in, but watching the colour drain from the borders can make the scene somewhat depressing. So finding plants that are only just getting into their stride at this time of the year is almost enough to make me dance on the dew-drenched grass. Here are some late bloomers that will keep going long after the summer flowers have faded: Hydrangeas come into their own now, having spent most of the year as unassuming, dull lumps of foliage.

The flowering heads - panicles, mops or lacecaps, so useful in dried arrangements, are formed from bracts, not flimsy petals, so they stay on the plant indefinitely, gradually mellowing as the season progresses. Hydrangeas thrive in damp shade - the large Paniculata types look good as specimens among other autumnal shrubs and trees, while the more modest mopheads and lacecaps can even be grown as an informal (ie slightly untidy) hedge. Asters are another stalwart of the season, merrily flowering away when all else has given up.

I confess it's taken me a while to love them, as they remind me of the neglected front gardens I walked past as a child, when forlorn and straggly old asters, in shades of old lady purple, were the only thing left among the brambles and nettles. Nowadays they're very welcome and I admire their tenacity (how age is mellowing me). They come in quite a range of sizes and colours, are long flowering and, like most of the daisy family, are very attractive to bees and butterflies.

Rudbeckias, also in the daisy family, are as easy as asters. Unfussy and cheerful, they clump up nicely and mix well with other plants in the border. They are yellow. I know lots of people find them brash - yellow, especially the hard mustard tone of some of these, can be tricky to incorporate into classic pastel schemes, but by October the light has changed; the sun is lower in the sky and more forgiving. Rudbeckias are like a last blast of golden sunshine. Let's embrace them. Verbena bonariensis, despite its unpronounceable double-barrelled name, is hardworking and humble, flowering resolutely from June until November.

It is also a wonderful source of nectar for beneficial insects and despite looking fragile, stands up well to autumnal weather. It comes into its own when weaving its airy, stems serendipitously among other plants at the back and front of the border and will self seed all over the place if it likes you. Claggy clay soil is not as welcoming, but if you garden in more free-draining conditions, you may need to steel yourself for some judicious weeding to stop it taking over.

Gaura lindheimeri is another airy, delicate looking plant that starts to flower around the same time as Verbena bonariensis (in June) and keeps on going until cut back by the frosts. It does prefer a light, free-draining soil and, being a native of Mexico, a sunny spot, but it is a beautiful plant if you can give it what it needs; the pinky-white Gaura lindheimeri 'Whirling Butterflies' is the one to go for - who can resist a plant called whirling butterflies? Sedum spectabile is an all round useful plant, with its fleshy, succulent leaves, attractive buds, flowers and seed-heads. It's an invaluable nectar source too and will teem with grateful invertebrates in late summer.

It carries on looking good for ages after that, as the flowers gracefully fade from pink to bronze and the old flowerheads look good even in the depths of winter. Keep sedum low and sturdy (it's inclined to be top-heavy and will irritatingly flop open at flowering time) by giving it the 'Chelsea chop' in late May - ie cutting it back by at least a third - cruel, I know, but as I tell it at the time (while hacking off its happy little buds), ultimately it's for the best. Dahlias are still the dahlings for late summer and early autumn, gloriously showy and sumptuous and available in a huge range of colours and various flower shapes, but they're not hardy, so can be struck down by the frost at any moment - from September onwards.

Watch the weather forecast and pick them as cut flowers if a frost threatens - or you will find them all turned to black mush the following day, as if a bad fairy has visited in the night. Once dahlias have been (lightly) frosted, the next dilemma is whether to lift them, as the tubers are also killed by freezing temperatures. If you like to cram plants into borders and plant in succession, making the most of your garden space, then lifting them (thereby clearing space for early bulbs and spring bedding) makes sense. If you decide to leave the tubers in the ground, make sure you cover them up with a thick layer of mulch - and then hope for the best. I don't lift mine, but sometimes lose a few.

Penstemon are hardier than they look and are very easy to grow. When they do eventually finish flowering, leave the stems to die back over winter, as this will protect the plant from the frost. Cut back all the tatty old growth hard in the spring when the new stems start coming through. They're really easy to take cuttings from too and will grow in a range of conditions, although they do prefer a sunny spot. Salvias provide another welcome shot of late colour and can confusingly be wide ranging in form and colour, from the dumpy, scarlet annual bedding plant, Salvia splendens, to tall and airy perennials, such as S. 'Cambridge Blue' and a myriad in between - annual, biennial, shrubby, you name it, there will be a salvia to suit.

They are all part of the sage family - Salvia officinalis is the culinary sage, and all prefer a sunny spot in moist, free draining soil. Nerine bowdenii, with its candy pink curling petals looks incongruous in the autumn border, as if it should belong to another season altogether. Like many garden plants at their best now, it belongs to another continent (South Africa) and is just doing its best to rub along. Plant it somewhere sheltered, sunny and free-draining and it will spread gently.

It will also grow well in a pot, so you can move it around - a splash or two of that sugary pink mingles surprisingly well among the tawny autumn shades. So, just when we thought it was all over, it turns out that there are lots of plants that have been waiting all year for their chance in the sun (or wind and rain) and quite a few that don't really get going at all until it's almost too late. I haven't even begun to mention all the plants that have fruits, berries and seed-heads, the ornamental grasses, the fiery foliage. It's definitely not too late to get out there!

Contact Jo for gardening advice and consultations on 01233 861186 email jo@hornbrookmanor.co.uk or visit www.hornbrookmanor.co.uk