“Being surrounded by trees and getting to know them . . . ripples of light on the bark caused by the sun on the trunks as it slowly goes down . . . an old oak at the top of the hill . . . shadows in the trees and the sun on the outer leaves . . . three big pear trees dead at the top, they look like hands clapping”: these, plus a little pond, are what David Hockney describes and makes monumental and crystalline in the Royal Academy’s unmissable reopening show.

Recording Hockney’s joy in observing nature during lockdown in his rural French home near Caen, acquired three years ago, David Hockney: The Arrival of Spring, Normandy, 2020 was always going to be the most cheerful exhibition in town. Its unexpected pleasure is how these ebullient depictions of an unspectacular few acres around a timber-framed house also muse on the long history of image-making — on its role and its possibilities now.

Entering the first, large gallery, you meet a frieze of single trees. Each branch is a curl of detail and individuality, flickering, coming into leaf. Together they coalesce into a drama of acute minutiae of seasonal change, harmonised by “many different greens” which are all “the green of the spring . . . a luscious fresh green that’s gone by about June”, as Hockney says. This group unfolds like moving images on a screen, but, as you walk along, there comes also to mind the graphic abbreviation and storytelling of the “Bayeux Tapestry”, a few miles from Caen, which Hockney quotes as inspiration.

All the works are titled only by number and the date they were made: a tree mostly bare, “18th March 2020”; fat buds in close-up, “25th March 2020”; the burst into flower, “26th March 2020”. Spring happens quickly, yet we watch it here in slow motion — even though Hockney fixed each moment fast, drawing on an iPad. Its benefits — practical, portable, small on-screen depictions convertible into big solid prints — were decisive because “any good draughtsman is interested in speed”.

You see that rapid virtuosity in a quartet of fruit blossom twigs hanging at the end of this section. Broken off, drawn lying on a table in the hours before they wilted, they are as delicately rendered, limpid and translucent as Manet’s late still lifes of flowers, but without the melancholy. “Cheerry blossom” Hockney has scrawled beneath, in a purple ink matching the dot-shadows cast by the blooms; then he has scratched a yellow cross through one e. Other bowls and baskets of flowers rest on red-and-white Bonnard tablecloths; at the opposite scale are panoramic views where a sun low on the horizon throws its diminishing last rays on rows of rounded hedges — a homage to Monet’s twilit “Haystacks”. Throughout, allusions to what Hockney calls “French mark making” are a delight.

A decade ago, when “The Arrival of Spring in Woldgate, East Yorkshire” was on show in these galleries, the contrast between Hockney’s iPad works and his paintings was stark, as even he admitted — “it’s the physicality”. Now his iPad Brushes app is more sophisticated, and he exploits it fully in increasingly layered, nuanced surfaces and greater detail of motifs. The results are not as textural as oil or acrylic on canvas, for these works remain prints — but elements summon resemblances to gouache, watercolour, pointillist dots, stippling, stencilling, and there are particular lively effects enhanced by the medium.

Among the show’s most ravishing works are night scenes of bright hanging moons. Full orbs or fat crescents emerge from smoky clouds to illuminate the trees and their long silhouettes as inky patterns, deep blues intensifying to velvety blacks. They defy iPad flatness.

“Actually I didn’t arrange to see the Moon,” Hockney explains. “I just got up to pee, saw the Moon out there, looked down and saw the shadows and thought, I’ll just draw this now. And because it’s an iPad you can do it just as you are, so I did . . . they could only be done on an iPad. If you did them on paper, you’d need light on the paper, you can’t really work in the dark out there. But on an iPad you can, because it’s backlit.”

All his life Hockney has embraced new technologies, experimenting across printmaking, photo-collage, theatre design, film, within a consistent aesthetic — lucid simplifications of line, form and composition; thrilling spatial vistas leading the eye into windows on nature; brilliant colour. They are all underpinned, as here, by his genius freedom of graphic gesture, and his optimism. “They can’t cancel spring” was his message sent — with an iPad drawing of daffodils — during lockdown last March. The image became world news. What other painter could do that?

Spring Cannot Be Cancelled, a new book accompanying this exhibition, is art critic Martin Gayford’s account, through email and FaceTime conversations, of what Hockney thought, read, remembered, during the year in lockdown. It reveals — and this lies behind the pictures and their apparently effortless clarity — Hockney as the broad-ranging intellectual, the global cultural strands bearing on these documentations of the Norman garden, for all that they remain quintessentially northern European in their shifting light and weather effects.

When Hockney talks, for example, of his admiration for Ad Reinhardt’s blacks in the same breath as Hans Christian Andersen’s fairy tales and his own 1981 Metropolitan Opera designs for The Nightingale, you understand the Moon pictures as enchanted stage-sets informed by modern abstraction.

Then there is the hinterland to the gorgeous, faux-naïf, stylised green-blue-grey pond. At once transparent, reflecting clouds and a whole tree spread and mirrored like a fan, and dense with the still masses of aquatic plants, it is both representational and a geometric construct with its puddle-circles and black lines of raindrops. Nearby Giverny is an obvious reference but Hockney is not trying to be transcendent late Monet. He tells Gayford an Andersen tale, “The Drop of Water”: “it’s about an old magician called Kribble-Krabble who magnifies a drop of water from a puddle and colours it pink with a drop of wine so all the little bacteria and creatures in it look like people”.

The magician shows it to another, who sees a teeming city, but Kribble-Krabble answers triumphantly: “It’s a drop of puddle water!” So Hockney too spins magic and spectacle. Naturalism is transformed by the vitality of imagination: not just his ponds but “all his pictures”, as Gayford concludes, “mirror the world and demonstrate how beautiful it is”.

Royal Academy, May 23-September 26, royalacademy.org.uk, then BOZAR, Brussels, October 8-January 23 2022, bozar.be.

‘Spring Cannot Be Cancelled’ is published by Thames & Hudson