Stop the War on “Invasive” Plants, They Do More Good Than Harm

The counterproductive war on “invasive” plants is funded by herbicide companies. “Invasive” honeysuckle has quadrupled native bird populations, purple loosestrife cleans up polluted waterways, Japanese knotweed is a staple for native pollinators, and kudzu heals soil damaged by human development.

For decades, environmentalists have towed the party line that foreign – or “exotic” – “invasive” plant species are always bad, and that no expense should be spared in the effort to eradicate them and “save” native plant species.

Author of the permaculture “Bible,” Gaia’s Garden, Toby Hemenway disagrees.

He addresses the important issue of “invasive” plant species in the opening pages of his best-selling guide to beyond-organic gardening.

The war on invasive plants is not only futile, it’s counterproductive, Hemenway argues.

“We may uproot some bittersweet or kudzu for a few seasons, but nature will keep reseeding it, year in, year out, waiting until we tire of the battle,” he writes.

“That’s one reason herbicide manufacturers are helping fund the campaign for native plants. They know a repeat customer when they see one.”

Agribusiness, governments and conservation groups have spent millions of dollars trying to eradicate “exotic” species, but they will never succeed, Hemenway says.

That’s because “invasives” – which he calls “opportunists” – are nature’s strategy for healing land damaged by human development.

“These are species that love sunlit edges, and we’ve carved forests into countless tiny pieces that have more edge than interior, creating perfect habitat for these exotics,” he writes.  “All that sunny space and bare soil is just crying out to be colonized by light- and fertility-absorbing green matter.”

“When humans make a clearing, nature leaps in, working furiously to rebuild an intact humus and fungal layer, harvest energy, and reconstruct all the cycles and connections that have been severed. A thicket of fast-growing pioneer plants, packing a lot of biomass into a small space, is a very effective way to do this.”

And thank goodness it does, otherwise lots of birds, bees and other wildlife would go hungry.

A recent study found that Pennsylvania’s population of native fruit-eating birds, such as robins and catbirds, has quadrupled in the last 30 years thanks to “invasive” honey suckle filling in deforested land.

Autumn olive

“Invasive” Autumn olive also oriental bittersweet also provide an important food source for struggling native birds, especially in the fall and winter. Japanese knotweed and spotted knapweed provide pollen and nectar for pollinators and many other “beneficial” insects.

Often an opportunistic species is playing an important role, where nature is working on a problem that we may not recognize and using the best tools available.

Purple loosestrife

For example, purple loosestrife, which is mainly found along polluted canals and irrigation ditches, turns out to be excellent at cleaning up polluted water, and tends to die back once the job is done, Hemenway says.

Kudzu, Scot’s broom and Russian olive are nitrogen fixers, which are great at making dead, barren soil fertile and alive again.


If you find yourself triggered by this article, and still thinking “native” plants belong in your backyard, ask yourself what Hemenway does: “Is a species native to this hillside, or this country, the bioregion, continent, or perhaps just to this planet?”

“I see a certain irony in immigrant-descended Americans cursing “invasive exotics” for displacing native species,” Hemenway adds.

“It is only our limited time frame that creates the whole ‘natives versus exotics’ controversy. Wind, animals, sea currents and continental drift have always dispersed species into new environments … for millions of years there have been billions of birds, traveling thousands of miles, each with a few seeds in its gut or stuck to the mud on its feet. And each of these billions of seeds is ready to sprout wherever the bird stops. The planet has been awash in surging, swarming species movements since life began.”

“I’ve often heard blame put on one or another opportunistic species when a native species goes locally extinct. That’s understandable. When we lose something we love, we search for a scapegoat, and a newly arrived species makes a ready target. But virtually every time I’ve examined that charge, it turned out the place had first been severely disturbed by development, logging or other human use. The opportunist moved in after the primary damage was done and often in direct response to it.”