Susan Bennett is an accidental teacher. “If you make me enjoy it, I’ll keep coming back,” she tells her classes at North London Collegiate School, where she has been a part-time ceramics teacher for 13 years. They do, and you can see how much she enjoys it.

The rest of her time, at home, she is a potter. Her partner, Earl Hyde, is a potter too. They pot together in a studio in a delightfully potty garden. And I can honestly say I have never visited a more enjoyable town garden.

Back in the 1960s, Susan was heading for a career as a folk singer but seriously cut her finger clearing builder’s rubble from her then new garden. She could no longer play guitar, and decided to turn to pottery instead.

Behind her garden (and almost everyone else’s in the row of terraced houses) was a little patch of neglected land which belonged to the Home Office and was let to a prison chaplain. She and a neighbour bought part of it for a song in 1974, and her garden boundary made its first extension into a patch of shady orchard.

She met Earl and they set up the studio in the garden. Together they shared a passion for old Victorian chimney pots, with pattern names like “Lancashire” and “Lady Broughton”. They collected for a while but their enthusiasm waned when they found they had to buy 100 at a time from demolition men to get one. Today they keep a few as planters, some Victorian, some made by Earl.

At the height of the property boom, the remainder of the Home Office land came on the market and Susan and Earl shelled out what felt like a king’s ransom and the garden expanded again.

Two and a half years ago, they bought the end of another adjoining garden, a stub of land covered in tarmac and trees, where previous owners had lit an annual November bonfire and indulged in costumed military re-enactments.

So stands the garden at present; a rectangular tree-girt oasis, as far from any of the surrounding houses as it is possible to be, and joined to their own house by a dog-leg. It is as quiet as London can get.

This year for the first time the garden is open for a couple of days under the National Gardens Scheme. When you see it, you cannot but be impressed by its extraordinary structures, the temple and the Japanese screen and gateway. But the planting is good too. It is not a place for rarities, but it is deliciously full of healthy, strong plants, filling the borders with not an inch to spare. There are buddleias, silver variegated dogwood, and, pouring out summer fragrance, a huge philadelphus.

Even more powerfully scented are regale lilies, standing firm in a bed of astilbes, delphiniums, and the tall late season yellow daisy, Rudbeckia ‘Herbstsonne’. The fences which enclose the garden are hidden by shrubs or topped with trellis supporting large-flowered clematis or the early, scented evergreen species Clematis armandii. And running along the edge of all the borders is a neat little ribbon planting of blue ageratum, lobelia, or scarlet busy lizzies.

But the eye is always drawn back to the structures. In one corner is a circular temple, not unusual in itself; but with dark blue marbled columns and gilded Corinthian capitals?

Beyond the studio is Earl Hyde’s screen wall, with mirrored openings framed in deep red glazing bars, and topped with red trellis and turquoise raku Japanese roof tiles, behind which sits Susan’s potting-up area complete with matching red greenhouse. He calls it her “forbidden city”. Under the wall is a besieging army of pots, all shapes and sizes, and filled with scarlet geraniums and yellow sedums. From among them stare the terracotta heads of a dozen children, like complicated pebbles. Nearby a grand brick gateway is under construction, with red wooden doors and panelled with mirrors.

Friends tease the couple about buying the next garden and expanding again. But this is the farthest limit. It may be fun gardening like this, but one has to work as well.

Earl specialises in porcelain architectural models and figurines. In a pond, humming with newts and toads, sits a perfect little Mississippi paddle steamer, with gilded flag poles, quietly aground in the irises. Elsewhere, against a fence, a blue marbled fibre-glass fireplace blazes with “flames” of mother-in-law’s tongue and scarlet impatiens.

None of this is done to be grandly arty or trendily modern. It is done for pleasure, and to garden around; and it really shows.

5 St Regis Close, Muswell Hill, London N10 The garden will be open on Sunday July 28, 2-8pm, admission Pounds 1.50 adults, children 50p. Teas and ceramics for sale.

Gardens of England and Wales Open for Charity, Pounds 3.50 and Gardens of Scotland, Pounds 2.50 available from bookshops