Hermitage, where the heel of Roxburghshire kicks into the once-lawless Debatable Lands, seems an unlikely place to find a botanical artist. It’s hard to make anything grow here, let alone an exhibition-load of rare and sometimes exotic plants. Lorded over by Hermitage Castle, a menacing hulk of medieval brutalism described by George MacDonald Fraser as ‘shouting “sod off” in stone’, this is a remote, rarely visited stretch of the border. Once the playground of reivers, and the graveyard of their victims, today it’s a land of sheep farming, forestry plantations and cruel May frosts. But there, hunkered against the wind in the foot of the Hermitage valley, is the studio of Emma Tennant, who has lived, farmed and painted here for more than 50 years. She is the daughter of Deborah Mitford and Andrew Cavendish, 11th Duke of Devonshire, but I suspect she might prefer to be acknowledged first and foremost as one of Britain’s leading botanical painters. Eighty is a bit old to be a nepo baby.

Tennant began painting in earnest while raising her family on the farm here, including the late designer and supermodel Stella. The work in this new exhibition emerged during the shattering months following Stella’s unexpected death in 2020. These 50 paintings, and the absorbing, and deeply scholarly, 128-page catalogue that accompanies the show, signal the therapeutic, perhaps almost meditative, benefits of both painting and gardening. Tennant explains: ‘For me, throwing myself into my work was the right thing to do.’ It’s hard to think of other things while concentrating on painting, and comforting to observe in detail a garden gradually returning to life.

The exhibition, Plants for Connoisseurs, charts the evolution of a garden through the year. Almost all the plants Tennant paints are grown in her own walled garden or in the greenhouse that leans against the outer wall of the Georgian farmstead that houses her studio. She takes me inside the former cart shed to reveal tables littered with paper, paints and empty frames, and walls hung with the paintings that will be on display in London.

It’s a captivating show, a watercolour portrait of a garden reviving itself, plant by plant. Tennant’s subjects are of a type. Not for her the garden centre’s bosomy modern hybrids. Her plants are tough, woody specimens that hunch against the textured Nepalese or Japanese rice paper like Giacometti figures, pressed in on all sides by empty space. ‘I love twigs,’ she says: ‘Old, gnarled, interesting shapes.’ The drawing is casually immaculate, observed with the trained eye of the botanist but, unlike fellow Borders plant painter Rory McEwan, she doesn’t go into granular detail. ‘I thought I was a line person,’ she says. ‘But it turns out I’m a colour person.’

The colours, from the range of greens in every glossy Lilium mackliniae leaf, to the psychedelic pop of a Paeonia tenuifolia bloom, leap from the paper. The habit of each plant is drawn out like a physical gesture; a Cyclamen persicum flops gently in all directions, a wiry honeysuckle (Lonicera tragophylla) undulates across the paper like branches of a river easing between hills. Tennant points out the subtle rhythms of her plants: ‘People buy a bunch of flowers and stick them in a vase and they’re all upright. But actually, a lot of plants don’t grow like that, even the ones which are vertical are often zigzagging. These things give the plant its individual characteristic. If you grow them, like I do, you’re very aware of the twists and turns.’

An apricot, Prunus armeniaca, is shown on the edge of blossoming (see below), with buds straggling along leafless branches that are half gleaming old wood, half fresh green wood. The blossoming branch is one of several nods to the elegant starkness of Chinese and Japanese botanical art and the oriental love of flowers erupting from leafless branches. ‘I like the idea of the garden growing,’ Tennant explains. ‘Most painters just do the finished product, the perfect rose, the perfect lily. I like it when things are just bursting into life.’ And then we meet the apricot again, later in the year, with its soft, buttocky fruit begging to be plucked. The spring apricot branch was painted in the unheated, derelict greenhouse at The Glen, the Tennant family home near Peebles, where the plant flourishes at an altitude of 750ft. The fruiting autumn specimen was grown by a local friend, near Langholm.

The catalogue provides a lively, erudite canter through each plant’s history. So beside the apricots, we discover that Confucius taught his followers in an apricot orchard, Alexander the Great introduced the fruit to Greece, Henry VIII brought them to England and now here they are, successfully eking out an existence in the furthermost reaches of the Borders – a storied journey. Paintings and prints of the same subjects by other artists reveal the diversity of plant art across centuries and continents and allow Tennant’s work to look eye-to-eye with some of the genre’s greats.

Tennant is self-taught, insofar as she never went to art school, but she learned from studying other artists and listening to advice from fellow painters. Growing up beside Chatsworth, with its world-class collection of Old Master drawings and Joseph Paxton-designed gardens and glasshouses, may have helped too. She cites Scottish painter Elizabeth Blackadder as a major influence and you can see her impact in the fluidity that allows intense colour to bleed through the confines of a Rosa moyessi’s petals or seep in an earthy pool beyond the ceramic pot holding a Forsythia viridissima ‘Bronxensis’. These soft, loose areas emphasise the economical tightness of the drawing elsewhere, throwing woody branches, needle-sharp thorns and knife-edge leaves into stark relief.

Tennant uses a mix of new and antique frames. She sources the old ones from a dealer in Melrose and will often design a drawing to compliment the particular shape and tone of the birdseye maple or rosewood. The new frames are exquisitely hand-gilded and made by her daughter Isabel, who lives half an hour up the road. Both types of frame are works of art in themselves.

Tennant paints two or three days a week from spring to late autumn, a decent shift for someone now in her ninth decade. She works only from life and only by natural light, which precludes much painting in the long, dark Borders winters. In the lightless, lifeless months, she turns to rag-rug making. She’s an authority in that field too. But in March, when the first bulbs arrive, she returns to the studio, always irrationally worried that she won’t be able to paint again, like an athlete who’s lost their fitness.

Perhaps because she only began painting in earnest later in life, Tennant is diffident about her achievements. She explains that she used to paint on the kitchen table, setting up while the children were at school, harried by the awareness of just how short the school day is. It takes dedication to work like this. ‘But painting was always waiting for me,’ she says. When the children left for boarding school it became serious, and she began selling her work.

Now Tennant is a sought-after botanical painter. The patronising dismissal of flower pictures as the preserve of amateurs and old ladies remains a source of frustration, but she’s fighting back. Her catalogue celebrates the rich variety of botanical art with drawings by John Nash, the eternally mind-blowing ‘paper mosaicks’ of Mary Delany, and Piet Mondrian’s unexpectedly blousy flowers all laid out alongside Tennant’s own studies of the same species. Add to that botanical masterpieces by Leonardo, Dürer, Lucian Freud and a whole garden of less familiar masters and you might have to conclude that flower painting isn’t just for old ladies. It’s art for connoisseurs.