The brief is a tough one. You live in a terraced house with a small concreted back yard. You don’t want to dig it all up and yet you desperately want a garden that’s not overlooked, which has a variety of lovely airy plants, a private area for eating and sitting out, and somewhere to put the bikes, hide the dustbin and hang the washing.

This is the kind of challenge that garden designer Paul Hensey, who himself lives in a small terraced house in the Ribble Valley in Lancashire, delights in. “There are lots of flagstone or concreted yards in Blackburn and excavating them to make a garden can be a bit of a nightmare. The solution is to put something over the concrete that allows you to make an enclosed garden, quickly.”

Hensey’s experience in product design – he has turned his hand to a wide range of everyday and industrial items from litter bins, seats and bricks to clips for roof tiles – enabled him to see the potential of a drainage system used on flat roofs, consisting of large, egg-box-shaped trays. The square compartments were modified so that they can either be filled with gravel for plants that need dry ground, or half-filled with water, which drains out very slowly, for plants that prefer damp conditions. This base, laid straight on to the concrete, can take up to 45cm of soil on top.

Hensey designed the blueprint for his own backyard. He wanted height, for privacy, and an exciting combination of plants that would give year-round interest. He decided to restrict his hard materials to just two – timber and galvanised steel, which would give the garden a crisp, contemporary feel.

The garden has two parts – a passageway that leads from the living room alongside the kitchen extension, and a square area enclosed by brick walls, with a door on to a lane at the back. He designed a circular oak deck for the centre of the main part, with a semicircle of oak and steel seating round a central steel pole which supports a sail-like canopy. A table big enough for four, fixed to the pole, can be swivelled around, according to whether Paul and his family want to eat in the sun or shade. Planting is contained in beds framing the seating area and on both sides of the passageway.

He linked the two parts of the garden by cladding one wall and the extension in planks of Scots pine, and the other two walls with a grid of galvanised steel.

Hensey laid out the garden in just one week. He has since tinkered with the planting, moving certain plants, taking others out. The result, two years on, is exactly what he had hoped for. Low grasses and lavender and scented climbers, grown in narrow beds, flank the passageway. The planting in the main area is a mixture of structural evergreens – phormiums, bamboos, ceanothus, grasses and clipped bay – and perennials such as hostas, heucheras, Echinops, alliums and Verbena bonariensis, which bring more foliage and colour in the summer. A passionflower romps over the back door while on the opposite wall, ivy forms a backdrop for a multi-stemmed birch, uplit at night for winter interest. The meshed steel serves as a rack for the family’s bikes. These, and the bin and various gardening equipment, are cleverly screened by a Phormium purpurea and bamboo. The washing line is a rectractable one.

One of the things that has delighted Hensey most is the rate of growth – the passionflower, planted in the deepest part of the garden and well mulched, put on an astonishing 27ft in one year. Sitting under the canopy, enclosed by rustling grasses, bamboos and phormiums, you feel as if you are in your own secret jungle.

Last year Hensey showed a wider public what can be achieved using this planting on top of concrete method with his Small Garden at Hampton Court, for which he won a silver medal. This measured just 5m by 4.5m, but again Hensey managed to create a sense of lushness, privacy and enclosure. Height was achieved with a series of rusted steel hoops, twined with ivy and Trachelospermum jasminoides, which drew you into the garden to the seating area, a circular deck at ground level overhung with rustling grasses. The planting had a relaxed feel, enhanced by the cool blues and whites of sedums, hostas, Echinops and aconitum. Hensey enclosed the plot with a fence made of woven metal which was then rusted to give a warm, textured effect. It was easy to imagine getting away from it all in this garden too.

Paul Hensey is designing a contemporary Small Garden, using rusted steel, for Hampton Court Flower Show (July 4-9), and a show garden, using grasses and perennials, for Tatton Park Show (July 19-23)

Design notebook

- In a small garden be prepared to take things out if they grow too big.
- Try to keep to just one or two hard materials, for a calmer, more co-ordinated look.
- High walls create microclimates, so choose the plants carefully

Something for everyone

Variety provides the spice for this year's Hampton Court Flower show

BACKGROUND

• Concrete jungle

• Out of Africa

• They live by night

• Remembering Milly

Explore Gardens

• Hampton Court Palace Flower Show

• Chelsea Flower Show

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