Reconsidering our approach to prolific spreaders

Few gardeners like a bully, and even eco-minded ones devote considerable effort to thwarting vigorous native spreaders. Common milkweed, Virginia creeper, jewelweed, blackberries, violets, goldenrods, mountain mints—these plants are often seen as grabbing more space than they need, pushing their way through the crowd and steamrolling over sensitive personalities. We all know the type.

Or do we? Maybe we’ve got it all wrong, rushing to judge plants that give much more than they take. Context is everything, and native species decried for their vigor are often simply strangers in a strangely denuded land. Maligned for centuries for their disruption of conventional farm and rangelands, these free spirits of the plant world tend to persist not just in spite of but because of our best gardening efforts. Their ability to spread quickly in our cultivated soils inspires disparaging, inaccurate labels like “invasive” and “aggressive,” despite their ecological value. You could even say that we ourselves are the bullies, repeatedly laying the fertile groundwork for certain plants to proliferate, only to then pull or spray them to oblivion again.

Rambunctious native spreaders are the real workhorses of any nascent wildlife garden, preventing encroachment of nonnative species that compromise habitat. Their density enhances important visual and olfactory signals to birds, bees and other animals who forage more efficiently among massed plantings. Rather than curtailing these hardy plants, I applaud their generosity—a divergent approach encapsulated in the words of designer and author Kelly Norris: “A reasonable gardener thinks, ‘What if things get out of control?’” he writes in his book, Your Natural Garden: A Practical Guide for an Ecologically Vibrant Home Garden. “A natural gardener thinks, ‘What if plants exceed all expectations?’”

From a Butterfly’s-Eye View

For many gardeners trying to tame plants gone wild, trouble begins when supply exceeds their own human demands. But of course, we’re far from the only customers. I was reminded of this last summer when two favorite spreaders, Maryland sennas and wild sennas, grew to their usual shrub-like proportions, abuzz with bumblebees on their yellow-and-black blooms. By August they had attracted a new clientele: caterpillars of orange sulphur and cloudless sulphur butterflies devouring entire flowers.

That abundant demand for senna encouraged me to increase supply by transplanting volunteer seedlings to new spots, ensuring that at least some will produce enough seeds for wild turkeys to enjoy. But not everyone shares my enthusiasm. “I will never, ever sell sennas,” a friend in the trade once told me. “They take over everything!”

Given the context of her landscaping work—small spaces; amended soils that encourage rapid growth; clients with unreasonable expectations for static plantings—her caution is perhaps understandable. Still, I lamented the lost opportunity for gardeners tending more natural spaces, where senna’s rambling ways would be balanced by competitors (other vigorous plants) and predators (voracious butterfly babies).

The Generosity of Density

From a landscaper’s perspective, prolific spreaders limit the chance to showcase a wide array of beloved species. As a plant lover, I understand the desire to have all the things all the time. But decades of observation and study have taught me that wildlife prefer concentrated patches. Flying around in search of needed resources drains energy, so a single goldenrod here and a couple of milkweeds there isn’t nearly as supportive as a dense planting of each. I’d rather see dozens of pollinators feasting on a large stand of a few species than a few pollinators desperately searching among singletons of dozens of different kinds of plants.

We’re a notoriously impatient species, with a mismatched sense of time and space. But watchful gardeners know that pioneer plants, in the absence of too much disturbance, eventually give way to slower growers. The live-fast-and-die-young habits of early successional species may explain why some thrive in cultivated spaces but struggle elsewhere. Wild senna has all but disappeared from some areas of its natural range, pushed out partly by ecological succession and development.

None of us will live long enough to see how floral and faunal communities adapt to more dramatic changes in the coming centuries. But at least we can build resilience now, watching formerly turf-covered land heal under the influence of generous plants. By shedding old tropes that have long hindered their popularity, we can help them embrace soil in their roots and birds in their branches while stitching fragmented lands back together again.

Powerful Partners

Vigorous spreaders offer inspiring alternatives to herbicides. I’ve overseen successful competitions between native plants and problematic introduced species, pitting golden ragwort against garlic mustard, Virginia creeper against English ivy, river oats against stiltgrass, and mountain mint against mugwort. Though species pairings vary depending on location and conditions, strategies for enlisting native plants as weed suppressors are universal:

•  Leave no ground uncovered. Nature abhors a vacuum; after removing unwanted plants, replant immediately. If resources are limited, transform small areas as time allows.
• Match plant personalities: Considering plants traits informs selection of effective pairings. When does the problematic plant leaf out? Is there a native that will break dormancy earlier to gain an advantage? Do the plants spread by seed or underground rhizomes or both?
• Think beyond low groundcovers: Some taller perennials, like penstemons, have basal foliage that fills in bare spots. Vigorous top growth of these plants and of suckering shrubs also helps shade out germination of unwanted species.

(A version of this article appeared in American Gardener magazine’s March/April 2025 issue. Bookshop.org links are connected to my author’s storefront, from which I receive 10 percent of any purchase. Thank you for supporting authors and indie bookstores!)