Reviewed by Judith Lesser

A weed is a plant in the wrong place, but British nature writer Richard Mabey defends weeds, agreeing with Ralph Waldo Emerson, who said a weed was “a plant whose virtues have not yet been discovered.” Although written primarily about the plant communities in England over the centuries, Mabey’s book, In Defense of Nature’s Most Unloved Plants, presents a compelling case that weeds, the opportunists of the plant world, play a vital role in filling the empty spaces of the earth caused by natural disasters or human events.

As temporary fillers, weeds can prevent erosion, conserve water, support insect and wildlife, and if attractive enough might be invited into the garden, become domesticated or even hybridized to produce a more sensational bloom. Mabey asks whether, like John Ruskin, we should judge uninvited flora according to human sensibilities (as something noxious to be removed) or by what they add to the natural world — what pheromones, chemical inhibitors or attractants the weed plant possesses. He brings to light a little known event in the life of one of England’s most influential scientific minds, Charles Darwin, who left a patch in his garden uncultivated simply to see what would grow there.

Mabey, editor of the Oxford Book of Nature Writing and author of the popular guide to foraging, Food for Free, is well known in Britain but may not be familiar to Americans. His writing style is dense, ruminative and encyclopedic, packed with information and anecdotes on every page. Weeds’ chapters are named for plants: from Adonis (another name for buttercup that gladdens spring meadows) to Triffid, a carnivorous invention of 20^th-century popular fiction and film. Love-in-Idleness (pansy or heart sense) inspires quotations from Shakespeare, whose natural metaphors alluded to the symbolic identities of plants for an audience well versed in that subject. Even the Harry Potter books rate a mention, for mandrake, always thought of as the magician’s plant.

But the main thrust of Mabey’s argument is that a plant can be judged a weed only according to its context. As an island with extensive commerce, Britain was the unintended recipient of weed seeds that came mixed in with other grain, hidden in the root balls of imported plants or stuck onto other materials. Some thrived and proved beneficial or attractive and were welcomed, and some fill the waste land of city dumps and along highways. Many more exotic plants were brought to Britain by the adventurous plant collectors of the Victorian and Edwardian ages. Although originally sought out to glorify gardens and greenhouses, some exotics did too well, escaped the garden borders and became invasive.

Plants that are intentionally planted in a non-native region can become uncontrollable. Mabey mentions the bane of parkland trees in the Washington area, kudzu, originally planted in the South as animal feed. Mediterranean, Asian and American species brought to Britain and promoted by William Robinson, the chief advocate of the orchestrated “wild” garden, have spread beyond the garden fence. Although the blooms of rhododendrons (originally native to the Himalayas) are supported and welcomed by landscapers and hungry deer in the United States, rhododendrons that have escaped and grow as understory in wooded areas are considered a nuisance in Britain. In other words, again, context is everything.

This is a wonderful book for the botanically minded who follow the spread and variations in our weeds and wildflowers in uncultivated places, including along the banks of Washington’s C&O canal. There one finds a steady progression of wildflowers in the growing season as well as escapees from cultivated gardens, including spring bulbs. It might seem fussy to object to any bit of bloom that deer do not eat, but if, like William Morris, one wants only native and non-hybridized varieties in the garden, Spanish bluebells (wood hyacinths or Hyacinthoides hispanica) are not an acceptable substitute for English bluebells (Hyacinthoides non-scripta). But then what of Virginia bluebells (Mertensia virginica)?  If unwanted in the garden they are treated like weeds!

In case you were wondering, Mabey finds no virtue in poison ivy, and after a brief mention drops that plant from his defense.

Judith Lesser writes garden descriptions for Smithsonian Gardens’ online Archive of American Gardens and devoted many years to continuous weed removal.