What to do in the garden in mid September

Bleddyn Wynn-Jones, of Crûg Farm Plants, Gwynnedd Holboellia latifolia is known for its ornamental evergreen foliage in 3–9 leaflets, like the spokes of an umbrella. These emerge purple to bronze, delicate as tissue paper, ageing to a parchment-like texture. The highlight comes in early spring when the clusters of flowers unfold, performing for 6–8 weeks before the sausage-shaped fruit takes over. Having grown the original species (from seed of hardier forms we collected in the Himalayas), we have now selected the best seed parents by the size and colour of flowers. H. latifolia will fill a space of 12ft with a dense cover of evergreen foliage, wafting its scent into the spring air. Clematis napaulensis is a good companion for it on a south-facing wall, flowering from December to March.

Graham Gough of Marchants Hardy Plants, Sussex The Siberian mallow, Althaea cannabina, introduced in 1597, has eluded me during a lifetime of looking at plants until last year when it came my way as seed, a gift from a customer whose selective eye I can really trust. The 10p-sized cupped flowers started their display in July. They are pale rose pink and darken to the base where, at close quarters, the apple-green calyx can be seen a charming combination. They are presented not as a voluminous wodge, but sparsely, and on a tracery of wiry stems, and even in September, the floaty display continues. It may prove short-lived, but I’m not too worried as it strikes from cuttings, and seed will be collected this autumn. Then I shall have the fun of partnering it in the garden next year with the beautiful and equally airy pale yellow flowers of the field scabious, Scabiosa columbaria ssp. ochroleuca. What a pretty confection that will be!

Ursula Buchan, author of The English Garden Early in the year, I saw Hydrangea arborescens Annabelle (above) recommended, so, on a trip to Burncoose Nurseries in Cornwall, I bought one. I’m glad I did, because it’s thrived during this wet summer. Since July, it has thrown up strong shoots with roundish, 10in heads of white, green-veined ray florets. It associates well with the blue-mauve Aster frikartii Mönch and the tall Aconitum carmichaelii behind it.

Sir Roy Strong, historian and gardener I discovered Crocosmia Gerbe d’Or (right) at Hidcote Manor, and I was entranced by its golden-ochre colour and fantastic leaf. I put it in an area of my garden that is dominated by perennials and drifts of grass surrounded by topiary; Gerbe d’Or is complementary to them all. Currently, I’m doing in a huge replant, and it’s a treasured part of the new arrangements. I didn’t break the bank in this era of credit crunch. I bought three and intend to let them multiply!

Kathryn Bradley-Hole, gardens editor of Country Life A year ago, I was given an amazing lavender, which apparently is at large in the nursery trade posing as Lavandula pinnata, although an authority on lavenders advises me that it is actually L. x christiana (above), a hybrid between two species native to Tenerife. In less than a year, it made a huge plant, which has never stopped flowering prolifically. It is said to be tender, but it sailed through last winter in our garden. Its wiry stems hold spears of intense violet-blue flowers well above the hummocks of filigree silvery-lime foliage. I pruned it hard a few weeks ago and it has rapidly regrown and produced plenty of shoots for cuttings, which is good because now I cannot imagine being without it.

Bob Brown, of Cotswold Garden Flowers, Worcestershire I have found the mundane raised to the level of the spiritual in Euony-mus japonicus Extase (left). It’s a short, yellow evergreen shrub, related to an old-fashioned, London-street-hedging plant. I have it permanently planted in several large pots, to which other seasonal plants are added. Its lucency gladdened my heart on the dullest days last winter. So far, it has only reached 14in, and there has been no reversion back to green. Sadly, it’s been given an ugly name and its originators recommend it for graves!

Jinny Blom, garden designer The soft rich orange of Erysimum Apricot Twist wouldn’t leave me alone, so I bought half a dozen. They flower and flower and flower, the colour is compatible with everything and yet they hold their own. They’re slug and snail resistant, and their streaky colour variation, developed over time, makes them even more lovely. But their energy is now spent, so I need to find some more.

Tania Compton, designer and author of Dream Gardens Coveted by all who see it, Heuchera americana Harry Hay was named by my husband after the iconic grower Harry Hay. A supreme performer, it bears leaves the colour of Bull’s Blood beetroot in spring and creamy panicles of flowers in midsummer. You can tug away at it to clean out dead stems and leaves in spring. Woody stems, pinned down and mounded with soil, will root readily.

Matthew Wilson, RHS head of gardens and creative development The bergamot Monarda Neon has been around for a couple of seasons, but I grew it at home for the first time this year. Gardeners are often put off bergamots because they’re prone to attack from mildew, which can be devastating in a wet year such as this. Neon, however, seems completely mildew-proof so far. It has unusual lilac-coloured flowers, which associate well with the cool blue of Perovskia Blue Spire and contrast beautifully with the dark-red Crocosmia Ember Glow.

Tim Longville, author of Gardens of the Lake District A friend recently introduced me to a pretty South African bulb, Albuca shawii (above), which flowers at a particularly useful time (August and September) and is hardy if you can keep it reasonably dry in winter. Its flowering stems rise to 12in–16in above a basal fan of narrow, dark-green ‘keeled’ leaves. Each stem holds an airy cluster of yellow, green-striped, saucer-shaped flowers. Some authorities suggest that both the flowers and the leaves have a pleasantly fruity scent, although I can’t detect it myself. This is not perhaps what Dante Gabriel Rossetti would have called ‘a stunner’, but it is a plant of considerable refined charm.