A look at the bright lights of late summer which will make your borders sizzle - plus, find out what else needs doing in the garden this week.

By Hannah Stephenson

While many summer flowers are now fading, Hannah Stephenson looks at the bright lights of late summer which will make your borders sizzle

My delphiniums and lupins are long gone, my roses are fading and the giant-flowered hybrid clematis are past their best, but my perennial borders remain a riot of colour thanks to a few, well-chosen gems.

Late summer can be a time when colour is at its hottest, when blazing crocosmia, burnt orange helenium, bright yellow rudbeckias, acid green euphorbias and an array of other plants come into their own.

Exotic orange ginger lilies (Hedychium), which release a great scent, clash with vibrant red Dahlia 'Bishop of Llandaff' or its relative D. 'Tally Ho', with its hot, deep orange flowers.

If you prefer pastel shades, plant sun-loving cone flowers (Echinacea) in shades of pink and white for a cooler, more subtle scene.

The daisy-like flowers and height (they can grow to 150cm (5ft) tall) mean they work well towards the back of the border, attracting bees and butterflies and adding impact alongside globe thistle (Echinops) and monarda.

Some varieties have rich colours that can be combined with fuchsias, or blue salvias. E. 'White Swan', a white variety with yellow centre, provides a cooling companion dotted within the hot border.

If you thought hard before summer started and were wise enough to plant some nasturtium seeds in your hanging baskets and patio pots, they should be now showing their true colours in a hot array of orange and yellow.

Clumps of bulbs are particularly useful in extending the season. Spikes of crocosmia will add architectural interest to the late summer border, their upright, spiky leaves with elegant sprays of orange-red flowers brightening the scene.

My favourite is C. 'Lucifer', a fairly tall variety growing to 120cm (4ft), which produces brilliant red flowers and looks wonderful grown alongside the purple-leaved smoke bush, Cotinus 'Royal Purple', or against a backdrop of acid-green evergreens.

Many warm yellow herbaceous perennials look fantastic in mass plantings, such as the long-lasting Rudbeckia fulgida 'Goldsturm' and late season heliopsis.

Bronze or burgundy leaves look fantastic mixed with the hot-coloured border. Place shrubs with red-purple foliage, such as Berberis thunbergii f. atropurpurea, behind red or orange plants.

The burgundy leaves of heucheras also make a wonderful foil at the front of the border, as their more vibrant companions show off from behind.

Other good choices include the herbaceous perennial Lysimachia ciliata 'Firecracker', a moisture-loving bronze-leaved plant with brilliant yellow flowers.

Use drifts of perennial border phloxes in the middle of borders to provide intense pools of summer colour. Herbaceous potentillas or small asters can be planted in front to hide the bare phlox stems. Phloxes are ideal follow-on plants for poppies and shouldn't need staking except in windy gardens. Don't let them dry out in summer as they need a moist soil.

Hotter subjects include red hot pokers (kniphofia), which produce rocket-shaped flowers, some red with yellow at the base, others a single colour, and the red tradescantia, T. 'Carmine Glow', a low-growing perennial (usually growing to around 60cm so perfect for the front of the border) with strap-like foliage which flowers until September.

Red varieties of astilbe such as 'Feuer' will give you coral-red flowers to September, above delicate feathery plumes. They thrive in moist ground in partial shade and can really brighten up a woodland scene.

If you want to add late summer-flowering plants to an existing border, buy as many of the same colour and variety as you can afford and repeat-plant them through the border to develop a sense of rhythm.

When mixing colours try to avoid using too many pastels with hot colours as the brighter hues will swamp the more subtle ones.

If you plan carefully, your sizzling summer colour can last right through to autumn.

Best of the bunch - Scabiosa

These long-lasting, dainty-flowered perennials, which can keep blooming from early summer until November, are a magnet for butterflies and bees and valued for their fresh and dried flower arrangements.

They prefer a sunny situation in chalky ground, although they can be planted in any well-drained soil. Plant in spring, protecting the young plants with slug pellets.

In summer they will need deadheading to prolong flowering and stems can be cut down in late autumn.

Scabiosa, which grow to around 60cm (2ft), make great plant partners for achilleas or sidalceas, which like the same conditions.

They aren't demanding plants, but need to be divided every two or three years to produce their best display.

Good varieties include S. caucasica 'Clive Greaves', which produces lavender blue flowers with pretty pincushion centres.

'Butterfly Blue' and 'Pink Mist' are also popular varieties which produce larger flowers on smaller plants (growing to just 25cm) and are ideal for containers.

Good enough to eat - Blackberries

Found in hedgerows nationwide, blackberries can be unbelievably expensive in the shops, yet amazingly easy to grow yourself to add to crumbles, mousses and pies.

Even if you don't have much space, there's a blackberry for you as you can buy compact varieties and one plant is usually enough to provide a harvest of around 3.6kg (8lbs) of berries.

Allow a 2m (6ft) run of fence for compact varieties and water well until established, adding well-rotted organic matter every spring. They will need wires to tie in the canes. In the first spring, prune the strongest stems to within 25-30cm (10-12in) of soil level to encourage new, vigorous shoots.

With established plants, prune by removing old stems which have already borne fruit, which makes space for new fruiting canes. The annual prune should be done when the fruit has been picked. Training in a new set of canes should be done at the same time.

They should be ready for picking from late summer, when the fruits are jet black and slightly soft. Good varieties include the thornless 'Loch Ness', a compact type which produces berries from mid-August, and 'Fantasia', which bears huge berries in late August.

Three ways to ... Deter cats

1. Plant your flower beds densely to cover the soil and make them less attractive as toilet areas.

2. Install an electronic cat-scaring device that produces ultrasonic sound.

3. Plant some thorny specimens, which cats will avoid.

What to do this week

:: Apply a high-potash liquid feed to dahlias, water regularly and tie in new growth to the stakes.

:: Prune espalier and cordon-grown apple and pear trees.

:: Plant summer varieties of strawberries to crop next year.

:: Start off the first spring cabbages.

:: Remove the growing tips of tomato plants in the greenhouse to encourage rapid development of the fruits on the top trusses.

:: Hand weed heather beds and replace mulch if necessary.

:: Harvest and freeze gluts of crops including French and runner beans and podded broad beans.

:: Plant madonna lilies (Lilium candidum) in a warm, sunny spot in well-drained soil, covering the bulbs with no more than 5cm (2in) of soil. They should start into growth next month.

:: Collect seeds from hardy annuals, harvesting them on a dry sunny day and popping them into paper bags. Store them in labelled paper envelopes in a cool, dry place.

:: Cut back wayward perennials which have spread over the lawn.

:: Trim faded flower spikes from lavender.

:: Continue to feed, water and deadhead container plants.

:: Keep mowing the lawn regularly, raising the blades if the weather is very hot and dry.