Hobbyists beware: “The Passionate Gardener” (McPherson and Company,340 pages,$30) is a guide to raising flowers in the same way that “Moby Dick” is an instruction manual for hunting whales. Yes, there is plenty of botanical knowledge packed into this teeming, rhapsodic, deeply humane book. Rudolf Borchardt, a German novelist, dramatist, and translator who died in 1945, was clearly an expert gardener, and his pages are strewn with practical advice: what type of soil a rhododendron needs (“free from chalk, and decidedly acidic”); what kinds of leaves should never be used as compost (“All remains from conifers, which are saturated with tannin, and poplar and plane-tree leaves … are excluded”); how to separate weeds from seedlings (“two of the fingers of the left hand gently hold the plant itself to the ground”). But Borchardt is more than a gardener: He has that love for the mere names of flowers that betrays the obsessive and the poet. He lists breeds in Homeric catalogs, as though naming were a form of possession: “Aster gracilis, with the light of the face of a child, Salvia carduacca, the phantom sage, sand phlox and lily bushes build flickering groups and lead the way to white and yellow prickly poppies, to the yellow horned poppy, to the horned poppy in dark ochre, the sand thistle which ripens blue, the ragwort that ripens white …” One does not need to be able to recognize all these flowers to share Borchardt’s verbal intoxication. Blossoms transmuted into language have a seductive power of their own, as poets have known since Shakespeare wrote Perdita’s speech in “The Winter’s Tale”:

daffodils,
That come before the swallow dares, and take
The winds of March with beauty; violets dim,
But sweeter than the lids of Juno’s eyes
Or Cytherea’s breath; pale primroses
That die unmarried, ere they can behold
Bright Phoebus in his strength — a malady
Most incident to maids; bold oxlips and
The crown imperial; lilies of all kinds,
The flower-de-luce being one!

It is in the same scene that Shakespeare proposes the paradox that “The Passionate Gardener” sets out to explore. For the flowers we tend to see as the jewels of nature are in fact the product of human cunning: They are the result of hundreds or thousands of years of deliberate, selective interference with nature. Breeding flowers, as Shakespeare says, “is an art / Which does mend nature, change it rather.”Yet as he goes to insist, “the art itself is nature.” If human beings are themselves part of the natural world, then our efforts to modify that world are not interference, but a higher expression of its energy and order.The garden is the point where nature and human nature intersect and interact, producing something that is natural and artificial, intelligent and inanimate, all at once.

No wonder, then, that Borchardt finds the garden such a fruitful subject for meditation. He is one of those writers — like Melville, or the 17th-century essayist Thomas Browne — for whom the choice of subject is almost irrelevant, since it is merely the starting point for endlessly ramifying digressions. Thus Borchardt can begin by considering a window box of blue petunias in a slum apartment — a shrunken, pitiable effort which nonetheless shows “the essence of the human garden” — and within a few pages find his way to the Garden of Eden, the Elysian Fields, Calypso’s island, and the lilies of the field from the Sermon on the Mount.

Not that his field of reference is strictly, or even primarily, literary. “The Passionate Gardener” is also a compact history of gardening, from the Hanging Gardens of Babylon — “the apex of the art of gardening as the whole of antiquity knew it” — through the nearly flowerless gardens popular in the Roman Empire, to the artfully artless flower gardens of the German Baroque, to the botanical gardens that flourished in the age of exploration. Borchardt especially admires the intrepid botanists who brought back exotic species from around the world, thus giving an example of nonviolent heroism: “Capuchins and Jesuits as missionaries, envoys to the Indies and officers, voyagers of discovery and plant collectors, all of them filled their collection bags and plant boxes in the wilds of every continent.”

In his own time — “The Passionate Gardener” was written in 1938, though not published until 1951 — Borchardt believes that the best gardens are found in England. He particularly admires the amateur spirit of English gardening, a practical, calm, and patient process, as conducted by a people who found it customary for each to go his own way, to allow others to go their own, and to reserve the conduct of private life, endeavor and activity, even to the point of eccentricity, entirely to one’s own guidance, free from any need of anyone’s authorization.

For a German writing in the 1930s, such a statement was inevitably about more than just gardening. Indeed, to fully understand what Borchardt is doing in “The Passionate Gardener,” it is necessary to keep the circumstances of its writing in mind.Borchardt was an active participant in German literary life, a frequent correspondent of Hoffmannsthal and Buber, among other luminaries. But he lived most of his adult life in Italy, and during the Hitler years, his strong anti-Nazi views and remote Jewish heritage made him persona non grata in Germany. Only after the war did his reputation revive, with his collected works gradually appearing in a 16-volume edition.To this day, he is almost unknown to English readers: This edition of “The Passionate Gardener” is the first of Borchardt’s books to appear in English. (Henry Martin’s translation, while it does not always avoid the echoes of German idiom and syntax, is rhythmically appealing, and deals admirably with a huge number of technical terms.)

In writing about gardens and gardening, then, Borchardt also, inevitably, was writing about the catastrophe of European and German humanism, whose last representative he felt himself to be. For him, gardening is not merely an aesthetic pursuit, but an ethical discipline, and it raises the most profound questions about man’s relationship to nature and art. That is why each of Borchardt’s maxims about gardening carries an unmistakably wider application. When he praises English amateurism and individualism, the struggle between democracy and fascism is not far from his mind.When he describes the golden age of German gardening, in the 17th century, as a triumph of cosmopolitanism — the fusion of Asian and American breeds with native plants — he is implicitly rebuking his contemporaries’ narrow, xenophobic idea of Germanness.

Above all, and most important for readers today, Borchardt addresses the concerns of what we now would call environmentalism. Ideally, the garden is the site where man engages nature without defeating it, an encounter Borchardt expresses as “the eternal tension between the flower and the garden. … The order within the flower is prehuman, and governs the flower itself. The garden speaks of human modes of order, where man is master, subduer, and transformer.”The key to a successful garden, he insists, is to maintain “the wealth of this tension,” allowing the gardener and the garden, nature and humanity, to work in partnership.

But the standard modern garden, Borchardt complains, annihilates this tension by turning flowers into mass-market commodities.He is never more “passionate” than when railing against the philistine householder who wants to plant hardy, banal flowers in premixed soil, thus creating a foolproof garden that requires no work or imagination. This is the gardener not as creator but consumer: “A garden that does not owe at least half its creatures’ strength and vigor to the gardener’s constant love and attention, a garden which instead is so ‘ready made’ that love and hate can make no difference to it, is simply a whitewashed grave.”

Borchardt’s critique of the commercialization and industrialization (and, not incidentally, Americanization) of gardening runs parallel to the critiques of modernity made by many right-wing German writers between the wars.There is a potentially reactionary element in Borchardt’s grievance, an implicit nostalgia for a more organic and hierarchical society. But Borchardt, to his credit, does not allow himself to be ensnared by such fantasies.

His is finally a profoundly democratic vision: Every man should be his own gardener, he insists, the poor no less than the rich. Gardening is not a luxury, but an essential human activity — indeed, one of the ways in which we learn what it is to be human. For a reader hemmed in by concrete, with no green space to plant, “The Passionate Gardener” offers the salutary reassurance that “when times are stark, the garden too will be stark, but a garden will be there. In arid times, charged with anxiety, bleak and insecure like our own, the garden will be a sandpit, but will not be missing.”