Blooming autumn

Asteraceae. Admittedly, it's not the prettiest of words. Nor is it the easiest to pronounce (blame the plethora of syllables and that confusing "ae" dipthong at the end), but this vast and most diverse of the plant families – more commonly known as the daisy family – contains many of the brightest stars of the autumn flower border.

The most obvious example is the dahlia, that loveliest and showiest of plants whose jewel-coloured blossoms light up the garden from July until the first hard frosts. Take a good look at its flowers (technically “inflorescences”) and you’ll notice that each is made up of rings of petals (technically “florets”) arranged around a central “button”, just like the humble daisy.

The very same flower shape can be seen in many of the other brilliantly colourful stalwarts of the autumn flower garden; fiery heleniums, sulphurous-yellow coreopsis, golden rudbeckias, burnt-pink echinaceas, chocolate cosmos, Japanese anemones and asters are all members of this hugely decorative plant family. So, too, are many of our favourite and most long-flowering annuals, including pot marigolds, sunflowers, zinnias, cornflowers, Cosmos bipinnatus and Cosmos sulphureus, all of which are still in hearty flower in my own plot.

An autumn garden filled with at least some of these plants brings a special kind of pleasure. Not least is the joy of watching plants erupting into vivid bloom at a time when so many others have long ago begun the slow, sad, seasonal descent below ground. There’s also the very welcome bonus of fresh looking foliage all summer long. By September, plants that were a highlight of the June border – oriental poppies, sweet rocket, campanulas – are tatty reminders of the fact that summer is gone. Not so a border filled with the sparkle of autumn-flowers, which is a celebration of the season “of mists and mellow fruitfulness”.

Who could look at the giant, tangerine-orange flowers of Dahlia 'Mrs Eileen' without breaking into a grin? Or sniff the cocoa-scented, velvety blooms of Cosmos atrosanguineus 'Chocamocha' without revelling in its Willy Wonka-like beauty? It's hard to feel downcast about the arrival of autumn when faced with the black-eyed, brilliant yellow flowers of Rudbeckia 'Goldsturm', the burnt orange daisy flowers of Helenium 'Sahin's Early Flowerer' or the lime-green, delicately frilled prettiness of Zinnia 'Envy'.

But it's not just about the pleasure these flowers give to humans; insects love them too. The inflorescences of many members of the Asteraceae family are rich sources of pollen and nectar, an important consideration in the autumn garden when so many other supplies have dried up. Take a walk along a border filled with these twinkling stars and you'll be able to enjoy the sound and sight of honeybees, hoverflies, butterflies and other pollinating insects savouring a September banquet.

Single flowers (rather than the multi-petalled doubles) are generally best in this regard, for the reason that the nectaries of the latter are harder for insects to reach, or they no longer properly function. As always, there are exceptions. Of all the dahlias that I grew this year, the bees' favourite by a long shot has been the dark-leafed, peony-flowered, semi-double D. 'Rosamunde'. I've rarely seen one of its golden-eyed, deep-pink flowers without at least one drunkenly stuporous bee clinging to its centre.

Not all members of the Asteraceae family have obviously daisy-shaped flowers. An example is Eupatorium maculatum, or Joe Pye Weed, a very tall, clump-forming perennial whose clusters of nectar-rich pink/purple flowers appear in late summer/autumn and are a powerful magnet for bees and butterflies. Make room for a clump (you'll need at least 2 sq m, while the plant itself grows to 1.5m-2m in height) and you'll be rewarded by the sight of Tortoiseshells, Red Admirals and Peacocks sipping nectar from its flowers.

Another giant of this family worth growing for its nectar-rich autumn flowers is Silphium perfoliatum, a hardy perennial with resinous foliage and bright yellow flowers, whose seeds also provide food for garden birds. Try pairing it with tall dahlias and the purple- flowering Aster 'Violetta', or plant the latter alongside the cerise-flowering A. 'Andenken an Alma Potschke' – the flowers of both these asters (also members of the daisy family) are equally enjoyed by bees and butterflies.

Finally, whatever plants you choose, glue the display together with grasses such as the tall Stipa gigantean and the low-growing Stipa tenuissima as well as the classic, purple-flowering Verbena bonariensis. Give a woody background in the shape of richly colourful foliage shrubs such as Cotinus coggygria or the black elder, Sambucus nigra f. porphyrophylla 'Eva'. Then sit back and enjoy what should be a brilliant display of autumn fireworks.

Diary dates
September 22nd: Open day at Woodville Walled Garden, Kilchreest, Co Galway, with guest speakers Klaus Laitenberger of Milkwood Farm and Carl Wright of Caher Bridge. Admission €10, see woodvillewalledgarden.com; September 27th-29th: Special Centenary Flower Festival in the Adelaide Memorial Church in Myshall, Co Carlow; tel: 087-2504322