The garden at Bryan's Ground, three acres of intimate garden rooms that have been growing since 1912 and are furnished with follies and fragrant flowers, towers and topiary, pools and a potager, and paths leading to an arboretum, surrounds a handsome Arts and Crafts house owned by Simon Dorrell and David Wheeler. The house was designed in 1911 by Hereford architects Groome and Bettington for a pair of sisters, Elizabeth and Molly Durning Hold, heiresses to one of the UK's larger shipping companies, Blue Funnel Line of Liverpool. It's said that some of the architecture details in the house were done by carpenters from the shipping line.

David admits that the two of them are "ambitious gardeners", who were fortunate to "inherit a very good bone structure - the garden was a sleeping beauty" and the garden has been extensively developed and expanded since 1993.

"The joy of making a garden is growing it alongside you," says artist and designer Simon, adding that he will always try to dissuade clients from buying mature trees. "If you are interested in plants, you're just as interested when they're three feet tall as you are when they're thirty feet tall."

"All the trees we've planted came here in the boot of my car," says David, who is responsible for the five acre arboretum developed at Bryan's Ground since 2000. (The grounds extend to more than 20 acres, though the formal gardens take up 8.5) "There are around 700 specimen trees and shrubs doing fantastically well he reports. "I originally planted it for autumn colour but now I collect hydrangeas from France, Holland and England. The current number of specimens in his hydrangea collection has reached 400. "They are David's greatest passion," says Simon, "It's bonkers. He swaps them all over Europe."

There are also Japanese maples, flowering cherries, sorbus, all sorts of things, so that there's something of interest all year round - whether it's for the bark or foliage, berries of flowers - the witch hazed flowers at Christmas."

"The remaining space, three acres, has been subdivided into more formal garden rooms, and we made gardens within those spaces." Shrub-filled borders and a lime walk for example lead to the sunken garden with a ninety-year-old box parterre planted with old roses and Irish yews. A small lily-pool at its centre is said to have been admired by George Bernard Shaw, who was a regular visitor, as was Lloyd George.

I ask which bits of the garden represent the greatest triumph and David's immediate response is 'that it hasn't killed us yet', which he follows, on a more serious note, with the observation that it's chiefly Simon's design - "its unity and complexity is down to him. It's like a Swiss watch - it has so many bits but they all link together and function beautifully as a garden you can progress through, with different surprises as you go." He adds that, for the two of them, Bryan's Ground is 'quite a big playpen'.

"I am more interested in the built structure of the garden and creating the design," says Simon. "I came to gardening through a love of architecture, so if I want something white and fluffy, I don't care if it's cow parsley or a named species - it doesn't have to be a cultivated plant, and that's where David and I differ hugely, but it does work!"

Throughout the garden, the visitor's eye is drawn - led - by that design, ensuring that it alights on something of interest around every corner and, beyond the garden, to the landscape beyond.

"I do have a nice collection of ground elder," he says, explaining the challenge of a garden on such a big scale with little help, adding that many of the species plants are in often in battle with native plants, but "It's nice and people seem to love it."

Simon is a self-confessed enthusiast for a folly and is currently working on a new addition, The Lantern, which overlooks the front garden and joins the wonderfully named The Sulking House, a Gothic Folly. He has also completed two Lightboxes which are boxed-in platforms with a bench on, and sited at the end of two vistas leading out into the landscape. "I also built a garage for David," says Simon, "but that doesn't count."

"In a sense, the formal gardens are becoming more wild," says Simon, "as we let more and more native species become part of the garden - in a sense it's becoming a formal wild garden. We wanted that boundary between the formal and the landscape beyond to be more natural."

Bryan's Ground, Stapleton, Presteigne

Instagram @bryans.ground

01544 260001