Olivia Laing’s new book, The Garden Against Time, is as fragrantly replete as a long border at its peak. The word that comes to mind is spumy: a blossomy, brimful excess that’s almost too much at times. Here are hundreds of plants, exquisitely described; here is colour, energy and expertise. In a way, it’s akin to a garden itself; a place, almost a park, in which the reader never quite knows what’s around the next corner. But while this is invigorating – my imagination whirred across the verdant expanses of its pages like some crazy, old-fashioned lawnmower – it’s also tiring. Dizzy on its pollen, I often had to put it down. I began to think of the chapter breaks as conveniently placed benches on which I might for a while sit quietly, temporarily unassailed by endless common names, ongoing worries about honey fungus, and long disquisitions on privilege and exclusion.

Laing does two things at once. First and foremost, this book is a memoir, in which she describes her restoration of the garden attached to the house in Suffolk to which she moved in 2020, as Covid-19 raged on and so many of us sought respite in our backyards, balconies and window boxes (in the course of 2020, more than 3 million people in Britain began to garden for the first time, nearly half of them under 45). All her life, she has longed for a garden to call her own – one she would never have to give up on the whim of some landlord – and now, at last, she has one, bought with her husband, a retired Cambridge don. The work originally of a designer called Mark Rumary who liked hedges and ponds, this third of an acre cannot be seen in its entirety all at once, appearing instead as a series of secretive rooms; a beguiling prospect for a woman who read Frances Hodgson Burnett’s marvellous novel The Secret Garden as a child.

But this narrative is mulched – somewhat buried at times – with deep thinking. When she’s not in her garden, pulling ivy from walls, Laing is in the library, dragging books from shelves. Among her cast of characters are John Clare, Iris Origo, Rose Macaulay, WG Sebald and, above all, John Milton, whose long poem, Paradise Lost, she reads for the first time during the pandemic lockdown. Such writers bring her to consider all manner of notions of Eden, whether utopian or built on sweeping entitlement, whether lost or found. This territory is often predictable. It’s hardly surprising to read that the beautification of Shrubland Hall near Ipswich, whose parkland was designed by Humphry Repton, was funded with money made from slavery; I’ve also read Laing before on Derek Jarman’s garden at Dungeness. Only when her material is less familiar does her research feel lush and fruitful. How gorgeous to read about the garden that the painter Cedric Morris and his partner Arthur Lett-Haines created in the 1940s at a Tudor house called Benton End; to picture the bombsites of postwar London utterly transfigured by wild flowers, as described by Rose Macaulay in her 1950 novel The World My Wilderness.

For me, though, the main event is the memoir. The literary and historical stuff is not half so infectiously written as Laing’s account of her garden; of her pruning and her planting; of her early starts, coat over pyjamas; of her late-evening visitations, chasing shadows. At first, this surprised me. If I’m the child of two botanists, I’m more of a reader than a gardener. But I already knew quite a lot about Clare, Milton and the rest (others may not); I preferred to languish in what’s basically a love story, with all the passion and intimacy this involves. I don’t think I’ve ever read a book that captures so well not only the deep pleasures and satisfactions of gardening, but its near-hypnotic effect on the human body and mind: the “self-forgetfulness” it induces, a “trance of attention that is as unlike daily thinking as dream logic is to waking”.

Laing restores her garden – two years’ labour, and she’s opening it to the public for charity – against a backdrop not only of Covid, a contested US presidential election and the outbreak of war in Ukraine, but also of anxiety-inducing events in her family. This brings the reader fully to feel the way autumn leaves, mud and seed catalogues may soothe a person, taking her out of her own head. I was envious, of course, not only of her lavish garden – photographs of which I’ve seen in the only glossy magazine to which I still subscribe – but of the immense amount of time she seems to have available to work in it (all mine is taken up with trying to pay my bills). But I tried my best to keep this at bay, like bindweed. And there is, in the end, a certain generosity here – or at any rate, a contagious energy, all secateurs and wheelbarrows – that has you looking at your own patch, however scant and small, with eager, nearly new eyes.

• The Garden Against Time: In Search of a Common Paradise by Olivia Laing is published by Pan MacMillan (£20). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply