Gardens: A desire for winter interest led rhododendron expert and author Ken Cox to experiment with a range of new plants

Peter and Patrica Cox may have moved to a smaller place nearby, but Peter retains a guiding hand on the five-acre woodland garden behind the property. However, it was in the formal, terraced garden that Ken decided to make his mark, and grasses were his chosen plant.

Experimenting with new plants is routine for the Cox family. Three generations, Ken, Peter and Ken’s grandfather Euan, have embarked on regular expeditions to remote parts of the world, such as the Himalayas and India, discovering and introducing an ever growing number of rhododendrons, magnolias, primulas, sorbus, meconopsis and much more.

Unsurprisingly the garden surrounding the Georgian mansion has long depended on the foliage of different Rhododendrons for winter interest. Many of these were retained, including the striking Rh “Everred”, with its dark red, nearly black winter foliage and “Wine and Roses” for the beauty of its deep green leaves reversed with claret.

Other beauties which survived include a mature, pink flowering Daphne bholua with the kind of scent that stops you dead in your tracks, and creamy flowered Viburnum foetans. The structure of a feathery Pinus wallichiana – grown from seed collected by Peter – on the bank behind the house was kept as the perfect foil for a drift of snowdrops.

Adding a range of softly textured grasses that rise up above the balustrades, move gently in the breeze and hold the frost was an inspired move. Drama has been added and the hard landscaping softened. But, as Ken explains, there was also a practical reason for the experiment. “I wanted something which would give interest in late summer and autumn and I wanted to trial grasses for my book Garden Plants for Scotland. I also wanted to test grasses planted into membrane with a layer of bark on top to keep weeds down and stop lots of reseeding.”

Key to the project was his conviction that the right grasses could do much to enhance our winter gardens. “Well planted displays of grasses can look magnificent well into winter, particularly with frost on the seed heads and stems,” he says. The seed heads can also benefit wildlife.

Inspiration came from Piet Oudolf’s one-acre naturalistic planting scheme at RHS Wisley as well as his contemporary planting scheme in the 18th-century walled garden at Scampston, North Yorkshire. Ken also looked at the grass and winter gardens which combine structure and colour at RHS Rosemoor in North Devon, and the striking winter garden at Sir Harold Hillier’s Arboretum in Hampshire. Closer to home he admired the grass and perennial plantings at Cambo House in Fife.

These garden visits also taught him the importance of choosing the correct setting to enhance the grasses. Here at Glendoick the cream harled house with its pink sandstone framed windows formed a spectacular backdrop especially after he introduced a back line of shrubs with red-purple leaves: Cotinus, Physocarpus and Sambucus.

For late summer the scheme was enhanced with “lots of colour.” During this season tall yellow Rudbeckia and waves of apricot Crocosmia form a striking contrast with tall, deep-blue Aconitum, purple Bear’s Breeches, Acanthus spinosus, and deep-blue Aster amellus “King George”. Softer hues were introduced with pink and white Anemone and mounds of long-lasting sky-blue Geranium “Rozanne”.

The garden visits taught Ken the importance of scale. “At the back I needed really tall grasses for height. Plumes of Pampas grasses and Stipa gigantica were introduced along with the “giant” sugar cane Miscanthus saccariflorus. “I thought the latter might be too tender but they have done fine,” he says. “The Stipa Gigantica has fountains of flower heads that tremble in the wind, in mid to late summer and usually last well into winter,” Ken says. The glamorous wavy Pheasant’s Tail Grass Anemanthele lessoniana proved too tender to survive recent cold winters.

Miscanthus including Silvery M var.c “Cosmopolitan”, orange tinted “Ferner Osten” and the pale purple plumes of “Flamingo” provided a succession of colour. The soft texture and low shape of Calamagrostis x acutiflora “Karl Foerster” makes it the perfect addition to any border; it also looks splendid in a container, frosted or not.

The trial confirmed that the somewhat shade-tolerant evergreen hair grass Deschampia could survive in a Scottish garden. Mass plantings of D. cespitosa, which also work in flower arrangements, were introduced as well as the tall bronze purple forms “Bronzeschleier”. Clumps of S. tenuissima are worth growing for its soft, silky texture, despite it being short lived, and in dry conditions it might self-seed.

Happily the new scheme proved very low-maintenance. Some grasses require splitting every few years but generally, “I cut it all down in February and do some weeding in season. And that’s about it,” says Ken. So how did Peter Cox feel about the innovation? “My father once stated ‘I’ve never planted a grass or a hosta and I never will’. I think he quite likes it now. But I didn’t put in any hostas.

“The key to grass gardens is that they look amazing in winter,” he continues. “The hoar frost has been spectacular. That is why I like good winter gardens such as Cambo and Wisley. Find a garden in Scotland that looks good in December or January and there is topiary, parterres or grasses. Get all three and you are really talking.”

• Garden Plants for Scotland by Ken Cox is published by Francis Lincoln, £25.

The garden at Glendoick is open every day from 1 April-31 May from 10am to 4pm, www.glendoick.com