“One afternoon in 1772,” writes the poet Molly Peacock, the 72-year-old widow Mary Delany “noticed how a piece of colored paper matched the dropped petal of a geranium. After making that vital imaginative connection between paper and petal, she lifted the eighteenth-century equivalent of an X-Acto blade (she’d have called it a scalpel) or a pair of filigree-handled scissors — the kind that must have had a nose so sharp and delicate that you could almost imagine it picking up a scent. With the instrument alive in her still rather smooth-skinned hand, she began to maneuver, carefully cutting the exact geranium petal shape from the scarlet paper.

“Then she snipped out another.

“And another, and another, with the trance-like efficiency of repetition — commencing the most remarkable work of her life.”

The Paper Garden” is a beautifully designed, eye-catching book — there’s a picture of an opium poppy on the cover — but it’s also as intricately made as Mary Delany’s paper flowers. Peacock doesn’t aim just to retell the sometimes chattellike, sometimes independent existence of an upper-class woman whose acquaintances ranged from Jonathan Swift and the naturalist Sir Joseph Banks to the King and Queen of England. Nor is she content simply to set up a counterpoint with her own background, career and second marriage (to James Joyce scholar Michael Groden). Instead, she weaves in and out between the two, using Delany’s flower mosaics as the starting points for reflections on love, family, art, friendship, illness and vocation. As Emily Dickinson observed, “The career of flowers differs from ours only in inaudibleness.”

Most important, perhaps, Peacock’s book is a celebration of second chances and the possibility — so attractive to those of a certain age — of an unexpected blossoming late in life. Certainly, Delany succeeded in creating a new art form, an early form of collage, and by the time of her death at 87 (in 1788), had managed to produce 985 examples of her paper marvels. As Peacock says over and over, and as the modern reader will confirm, it’s almost impossible to believe that these astonishingly realistic botanical images are built up out of little pieces of station­ery.

‘’The Paper Garden: An Artist (Begins Her Life's Work) at 72’’ by Molly Peacock (Michael Dirda)

Peacock reconstructs Delany’s life from the more than 3,000 pages of her letters — many to a beloved sister — and from the earlier scholarship of Ruth Hayden (author of “Mrs Delany: Her Life and Her Flowers”). Peacock’s own journey down the paper garden path opens with her first glimpse of Delany’s work at the Morgan Library in New York City, followed by years of circling before she finally decides to write about it. Thus, following the example of A.J.A. Symons’s biographical classic “The Quest for Corvo,” Peacock’s book is as much about herself and her experiences in tracking down Delany material as it is about the old lady herself. We hear of the poet’s alcoholic father, her high school sweetheart, her divorce, her affectionate conversations with the 86-year-old Ruth Hayden. At the back of the narrative, though, is a recurrent interest in those chief obsessions of later years: incapacity and death.

This takes a terribly personal form for Peacock because her husband suffers from melanoma and must regularly monitor his health. In one striking paragraph, she describes the muscular, normally assured and efficient Groden waiting for his checkup:

“But sometimes, sitting in a hospital gown on an examination table in Princess Margaret Hospital in Toronto, the man seemed to shrink to half his size, and someone else seized and froze his face, not the fleet boy but a static, narrow half-being, afraid and deathly still. It was as if he were diminished into a sculpture, all of the gestural energy that makes a person large sized down into gray stone. It was as if the blue snowlight from that freezing hotel room in New Hampshire” — where they first made love — “had funneled its cold energy into him but stunned him, as if he had become an illustration from a fairy tale. He was gone, lost to me, in a netherworld of ice that also was his youth, my youth, our first sex together now frozen and — dead. Suddenly he would mobilize on the gurney and lift an arm for the doctor, and become flesh again.”

Peacock’s sentences beautifully evoke the distressing diminution of self that affects people in hospital gowns, of whatever age. But note, too, that her prose pushes its wintry imagery hard, aspiring to an overtly poetic richness. “The Paper Garden” is written in just this emphatically lyric mode, which may tire some readers.

But there’s no denying the fascination of Mary Delany’s story, starting with her arranged marriage at 17 to a truly disgusting, fat old man in his 60s. Happily, at 23 she awoke one morning to find him dead by her side. Years later, she was resolutely wooed by a clerical friend of Swift’s named Patrick Delany, and the two passed a serenely happy middle life together. Only after her husband’s death did Mary experience her eureka moment when she realized that cut paper could emulate petals and sepals.

Along the way to that discovery, Peacock conveys an enormous amount about 18th-century English life. She discusses the practice of cutting silhouettes, spends two pages detailing the layering of clothes that an elegant lady’s ensemble required, touches on shell collecting, paper-making and close female friendship. She traces Mary’s tentative courtship by Charles Calvert, a.k.a. Lord Baltimore, whose two names echo throughout Maryland, his fiefdom in Colonial America. Such famous botanists as John Bartram and Mark Catesby make brief appearances. And, of course, Peacock describes how Mary Delany “selected plants in bloom, set up, and began to cut, carve, scissor, and position, reposition, think again, pose, re-pose her assemblage of botanical portraits.” Appropriately, each chapter of “The Paper Garden” begins with a full-page color illustration of a poppy, magnolia, thistle or other flower by Delany.

Here, then, is not only an introduction to a unique artist, but also a whole bouquet of thoughts and observations about the flow of life:

“To search a drawer or a pocketbook or a botanical bibliography, even to search a littered table or beneath the leaf of a geranium, means feeling for one’s conscience and one’s heart, looking for something that will complete — with a key, a tissue, a truth, a love, a victory, a seed — an instant of one’s being, or perhaps one’s whole life. In a sliver of knowledge, time is obliterated and reinstated. A single instance, the fall of a petal, or the swirl of the paper that imitates and becomes it, flourishes an answering likeness.”

Dirda reviews books for The Post every Thursday. Visit his book discussion at washingtonpost.com/readingroom.

THE PAPER GARDEN

An Artist (Begins Her Life’s Work) at 72

By Molly Peacock

Bloomsbury. 397 pp. $30