In old age, Monet said he took more pride in his garden than his art, and perhaps that is why the three-part panorama of water lilies reunited for the first time in decades at the climax of this show is so overwhelming – so magnificent. The bank has gone. All you see is water, flower, foliage, reflection, light, on and on, round and round. There is no up or down, no end to the beauty of these constellations of colour in liquid space and air. Monet’s garden is beautiful beyond measure: his field of vision is limitless. Shop discount not redeemable on the RA Online Shop. Offer not redeemable on RA Art Sales, books (except RA publications), limited edition prints or custom prints, limited edition books or limited edition merchandise and products. Offer not valid in conjunction with any other discount or promotion. Offer valid only on 6 April 2016

But there is a tension to this show. The curators want to woo the gardener from first to last: so there are 19th-century seed catalogues, horticultural specimens, cucumber frames and hothouse cupolas; real plants even bloom under cover. You may consult the detailed letters Monet wrote to one of his (six) gardeners for tips, and sit on teak garden furniture to watch a film of the master painting among the ponds at Giverny. Many of these men (only two women are represented) take little interest in the form and character of individual plants Like a film set’: Gardens of Monforte, 1917 by Santiago Rusiñol. Photograph: David Mecha Rodriguez/Colección BBVA Highlights of the exhibition will include a magnificent selection of Monet’s water lily paintings including the great Agapanthus Triptych of 1916 – 1919, (The Nelson-Atkins Museum of Art, Kansas City; The Cleveland Museum of Art, Cleveland; Saint Louis Art Museum, St Louis) works that are closely related to the great panorama that he donated to the French State in 1922 and that are now permanently housed in the Musée de l’Orangerie in Paris. It will be the first time this monumental triptych has been seen in the UK. This exhibition will be among the first to consider Monet’s Grandes Décorations as a response to the traumatic events of World War I, and the first to juxtapose the large Water Lilies with garden paintings by other artists reacting to this period of suffering and loss. Matisse barely makes it into this show, and neither does Van Gogh, so often out there among the blossoms. The two Paul Klees are dark, knotted and eerie. Munch’s painting of a rampant apple tree taking over the landscape is superb, and it is wonderful to see Pissarro’s warm-hearted painting of people actually getting down to work, hoeing and hauling. Like William Nicholson’s grave commemoration of Gertrude Jekyll’s old boots, this is one of the few images that alludes to gardening as actual hard work. The captions frequently indicate nasturtiums, but only one painter, Gustave Caillebotte, comes close to conveying their wildfire spread and colour, their tissue-fine frailty on such spindly stems. He paints them from above, as it seems, and drifting on a sea of mauve so that one sees anew their particular strangeness.As the nineteenth century drew to a close, Symbolists, Fauves, and German Expressionists embraced more subjective approaches by imagining gardens as visionary utopias; many turned to painting gardens to explore abstract colour theory and decorative design. In the early twentieth century, Monet emerges as a vanguard artist. The monumental canvases of his garden at Giverny anticipate major artistic movements that were to come such as American Abstract Expressionism. Monet died in 1926. The 20th century had even worse horrors to come than the slaughter that made his willows weep and it’s in that shadow that his painted gardens matter. They are glowing islands of civilisation and hope in a modern world guilty of so much barbarity and violence. Monet is not just one of the world’s greatest artists, he is one of the most moral.

For these artists and others, the garden gave them the freedom to break new ground and explore the ever-changing world around them. Highlights include a remarkable selection of works by Monet, including the monumental Agapanthus Triptych, reunited specifically for the exhibition, Renoir’s Monet Painting in His Garden at Argenteuil and Kandinsky’s Murnau The Garden II. This artist who was “only an eye”, as Cézanne put it, created in his garden a philosophical, scientific, poetic drama so enigmatic, it opens boundless imaginative vistas with its honesty. One moment, the reflected clouds and changing light on water seem all surface; another moment, infinitely deep – because that’s what Monet saw. His faithful paintings reveal we live in a world much stranger than we think. We ourselves are shadows, lilies, memories. Trace the emergence of the modern garden in its many forms and glories as we take you through a period of great social change and innovation in the arts. Discover the paintings of some of the most important Impressionist, Post-Impressionist and Avant-Garde artists of the early twentieth century as they explore this theme.But nothing can compare with the gardens of Monet, of course. And this show has so many of his works: white and yellow water lilies holding and reflecting the changing light; the bridge over the pond at Giverny, repeated in the water, over and again, at different hours of the day. There are those ravishing visions of the water at dusk, deeply darkly blue, carrying the last inklings of light in gauzy brushstrokes.