A carrion crow perches above a string of bird-scaring CDs on a ramshackle allotment. Tessa Newcomb’s sketch is a good joke but it’s warm and touching too, a gesture of friendliness, an acceptance that there are more important things in life than getting your own way. Comedy is not just about making you laugh. It’s also about the paradoxical beauty of insignificant things, about the joy of incongruity, about making the best of things. Shakespeare’s comedies rejoice in mayhem, but they are also about the reconciliation of differences, and what one writer called “the comedy of survival”.

The story of allotments began with a tragedy, the shameful process of the enclosure of the commons in the 18th and 19th centuries, and the few miserable acres of land the villagers were given by way of compensation. But it became a comedy, and a triumph, because of the sociability and dogged inventiveness of the allotmenteers. It’s their story that Tessa celebrates in this collection. It’s called, with the wit that infuses the show, The Adorable Plot. This being comedy, of course, the plot never ‘thickens’. But it does, in one wonderfully wild picture of spiralling fence-wire and runaway beans, ‘unravel’.

Mostly it meanders on, cheery, indomitable, blissfully unruly. Gardeners are swallowed up by exuberant vegetation. At the vegetable show they have other things on their mind: “Then we can have tea and a bit of that cake”. An empty wicker chair sits “watching the evening primrose”. There are gatecrashers and freeloaders: songbirds, abandoned tin baths, weeds so colourful they dazzle the dahlias. And always there is The Shed, where the Plot is hatched. Sheds lurk in corners, sprout weathervanes, shelter hens. Many have windows, and one has no roof at all. They are, you sense, places of a good deal of gossip as well as quiet retreat.

Tessa’s visual language is rooted in the highly local and vernacular tradition developed by painters like her mother, Mary Newcomb, and Mary Potter: a style one might call East Anglian magic realism. But she has her own unique signature, a wonderfully sympathetic fluidity of line. On her plot, plants and potterers bend to work and wind with the same easy grace. Using impressionistic, quickly sketched-in watercolour, she has included a series of pictures of gardeners at work. One of them, Big Men Become Gentle When Planting – a kneeling Adam, a supplicant to the soil, as softly rendered as the tissue of a flower petal – is a small masterpiece.

The allotment is one of our few modern common spaces. The best compliment I can pay to Tessa’s fond homage is to say her paintings are like allotments themselves, places where all manner of creatures, all kinds of eccentricities and obsessions, can find refuge and flourish.

Extract from The Adorable Plot www.sansomandcompany.co.uk See Tessa’s work from 4 September to 27 October at the Yew Tree Gallery, Cornwall www.yewtreegallery.com

Richard Mabey’s books include Nature Cure and Flora Britannica.