A pair of Frognal neighbours have teamed up for a garden show

�Neighbours from hell get a fair amount of press coverage, but to have neighbours you like and get on with is perhaps an under celebrated state. It would be tricky if Ruth Levy and Barbara Jackson and their respective husbands did not feel at all neighbourly because they come close to sharing a garden – or at least a garden path. But, in fact, they have, for several years, co-operated to open their adjoining gardens through the National Gardens Scheme (NGS) and will do so again on Sunday June 10. These are front gardens, deep and sheltered from the road by a row of limes, with a paved area for visitors to arrive to.

Ruth and Barbara say that, beyond a general understanding about colour, they do not consult closely about how to plant their shared path. The result, however, is so coherent that I was slow to realise that each side had been planted by a different person. Roses and clematis are the key to this unity. As the visitor arrives, Ruth’s garden is to the left, with three grey-green wooden obelisks supporting clematis (for example, Nellie Moser) to separate the path from the rest of her garden.

On the right hand side, Barbara’s trellis is also covered with clematis. Counting up throughout both gardens, there are about 35 different clematis. So, however strange this gardening year is turning out to be, visitors in June are sure to see some of them in flower. To have close planted borders full of clematis can be to invite slugs and snails. Nemaslug, Ruth says, is her answer, while Barbara uses a few slug pellets. As we were looking round, blackbirds, blue tits and a robin were ceaselessly active, in and out of the trees and ivy. There are thrushes, too. So one way or another, the molluscs are out of luck.

I had not known, while outside, that Ruth was an embroiderer. But once that had become clear, it cast a light on her careful use of colour and sense of scale – no yellow flowers in summer, for instance, and an awareness of the limitations of a small garden (actually it is only smallish). There is a bower at one end, which she had considered as a place for sculpture. But she decided it would be better with a planted urn since sculpture needs more space.

On a cold May morning with everything late to flower, the palette was still mostly green but white/cream/shades of pink and mauve seem to be the territory, with just one area for a “Christopher Lloyd” (ie strong colour) moment. A well-established Blush Noisette rose on the terrace should be in flower for the opening, similarly an old white/pink peony in the sunny bed and astrantias and hydrangea in the shaded herbaceous border.

Barbara’s garden is wider, creating a more open space, with grass in the middle surrounded by borders. It looks towards what is only the wall of a garage but has been made into an agreeable focus with the insertion of French windows. This is an arrangement which will come into its own for the serving of tea on the open day. Beyond, the lime trees form a backdrop.

Barbara says she is moving more towards a blue palette with her planting – although she did not specify what she was moving away from, a mix of colours perhaps. Clematis and roses, some of them growing up obelisks, will probably be the star turns of her garden in early June. But purple alliums should still be out, with astilbes under the weeping birch. Further towards the house is a flourishing herb garden and a Coprosma “Pacific sunset”. Whatever the intervening weather, visitors can look forward to two beautifully kept gardens which, like good neighbours, are distinct but complementary to each other.

The garden opening at 5 & 5a Frognal Gardens, Hampstead, on Sunday June 10 is from 2pm to 5pm. Teas and plants will be on sale.