Dear Members,
These days, it seems that when people make mistakes they just double down. Whatever your political position, I think we can all agree our government is full of politicians doing that. But in striving to make the native plant world a better community, we should do the opposite. Mistakes are something we can learn from.
In my last e-mail to you, I made a couple of gaffes and a few of you pointed them out, but rather than merely adding an errata section to this letter, I thought it would be interesting to spend a little time thinking about mistakes in the native plant world.
But, first, a reminder that we have our Weird NJ Plants conference at 8:50 in the morning of November 1, the day after Halloween—free to everyone via Zoom. The speakers and I created a slideshow full of creepy images, and our webmaster Marissa Bauman made a spooky logo.
Dead Man’s Fingers (Xylaria polymorpha), is a fungus that feeds on decaying hardwood stumps and roots, forming clusters of erect, black, finger-like fruiting bodies up to 8 cm tall, often emerging in temperate woodlands during spring and autumn. Photo courtesy, Jason Hafstad on iNaturalist.
Go take a look at the site and please share it with at least one other person, especially young folks like college and high school kids as well as people who have never thought about native plants. Let’s get them into a lifetime of fascination with the botanical world. If you have shared it with every last person you know in New Jersey, great, but we are delighted to have people from outside the state attend. Most of these plants live throughout the Northeast and Mid-Atlantic so let them know too.
Two more quick announcements: our Fall Newsletter came out last week and it focused on Weird NJ Plants. I also discussed the fall conference in the 25th episode of the Wildstory podcast, which features poet Holli Carrell, naturalist Mary Ann Borge, and another episode of Ask Randi.
Now for the last letter. I started with a typo: Trillium erectum not Trillium erechtum for the red trillium (or wake robin, purple trillium, or stinking Benjamin). Ouch. But that’s nowhere near as egregious as the caption in which I stated that American pokeweed (Phytolacca americana) is an annual. Of course it’s not! Pokeweed is a robust perennial with a large taproot. I knew this, but somehow the wrong neuron misfired when I wrote the caption, just like in my talk for NPSNJ last year when—inexplicably—I kept saying Cardinal flower (Lobelia cardinalis) when I meant Scarlet Beebalm (Monarda didyma). I know these things well!
But here’s the thing about mistakes: we’re all going to make them. What follows is my longest letter to date. Feel free to skip it, but I found this deep dive into native plant mistakes fascinating and I hope you do too.
Looking back at my own relationship with the land, I realize I’ve made mistakes. The worst was back in the early 1980s when my father and I decided to turn a meadow on our property in the Berkshires into a lawn. It was full of goldenrod (Solidago spp.) and sensitive fern (Onoclea sensibilis), but also invasives like Queen Anne’s lace (Daucus carota… and yes, it’s the wild version of the root vegetable) and mugwort (Artemisia vulgaris). Still, it was a lovely place, full of buzzing insects. We had no idea what we were doing. What were we thinking, destroying a thriving community?
At least my father and I had better sense another time. Foresters came by our house to explain that we could make money by having them log the wooded hill behind our house. We weren’t wealthy and more money was an appealing idea, so we visited one of their “managed” forests. They talked about the benefits of young forests for wildlife, but we both agreed it looked like hell. We ran. We never allowed foresters on our land and a good thing, too. At least part of that property contains old growth forest, something nobody knew until decades later. It’s still there, although it has been seriously hurt in recent years, not by logging but by Emerald Ash Borer and Hemlock Woolly Adelgid—themselves the product of serious mistakes in global trade. The borer arrived in wooden crates and pallets while the adelgid came through ornamental hemlock trees from Japan.
Unfortunately, I think a lot of us have stories like that. Well, we can’t change the past, but what we do now matters. Moreover, the history of botany and horticulture is full of mistakes, big and small. Common names for plants are full of them. Early colonists made countless naming errors because they tried to fit unfamiliar American plants into familiar European categories. They called our native juniper, Juniperus virginiana, “red cedar” even though it’s not a true cedar at all. Carl Linnaeus, the father of botanical taxonomy, made plenty of mistakes too. For one, he originally classified Twinleaf, now Jeffersonia diphylla, in the genus Podophyllum thinking it was a kind of Mayapple. It was only decades later that it would be understood as a distinct genus, although in fairness both are in the family Berberidaceae (as is the very different Japanese barberry, poster child of invasive ornamentals Berberis thunbergii).
Those are small mistakes, but there were plenty of big ones, sadly. In the 1930s and 1940s, the U.S. Soil Conservation Service actively promoted multiflora rose (Rosa multiflora) as a “living fence” for livestock and a solution for erosion control. State highway departments put it in medians as crash barriers. It seemed like the perfect plant—wildlife could eat its rose hips, thorny thickets would confine cattle, and it would stabilize streambanks. By the 1960s, alarm bells were ringing. Multiflora rose had escaped those farm hedges and was forming impenetrable thickets in pastures and woodlands, crowding out native plants. The same USDA that once promoted multiflora rose was now warning farmers to root it out. Decades of expensive eradication efforts followed—all because of a well-intentioned misjudgment.
The pattern repeated with autumn olive (Elaeagnus umbellata), Norway maple (Acer platanoides), and Bradford pear (Pyrus calleryana). Each time, experts thought they had the perfect solution: a hardy plant for reclamation, a replacement for elms lost to Dutch elm disease, a sterile ornamental that wouldn’t spread. Each time, they were wrong. These mistakes now cost us millions of dollars annually in invasive plant control.
But other mistakes get more complicated. Take the common reed (Phragmites australis), which now frequently chokes our wetlands. Until recently, I had thought that Phragmites was merely another invasive species. Well, that’s another mistake. Phragmites has been in North America for tens of thousands of years and Native Americans historically used it for arrows, mats, and ceremonial objects. Nonetheless, it was a relatively minor component of marshes, not the dense monoculture we commonly encounter today.
Researchers puzzled over how this native plant could suddenly become so aggressive. Perhaps it was responding to altered conditions in the landscape. In 2002, molecular ecologist Kristin Saltonstall compared DNA from century-old herbarium specimens with modern reeds and discovered a surprising explanation (you can read her paper here). The invasive Phragmites overwhelming the Northeast today is genetically distinct—a Eurasian strain introduced to North America in the late 18th or early 19th century. Genetic evidence clearly shows that this Eurasian strain (known as haplotype M) displaced native North American strains along the Atlantic coast and spread rapidly throughout the continent, facilitated by human activities such as transport and marsh disturbances.
Simultaneously, entomologist Lisa Tewksbury, et al. found that while over 170 herbivore species feed on Phragmites in its native European range, only five native North American herbivores attack it here (unfortunately, that paper is gated, but you can read a detailed guide she wrote over at NOAA). Botanists had long mistaken the invasive Eurasian strain for the native one, a phenomenon Saltonstall labeled a “cryptic invasion,” hidden by mistaken identity. Saltonstall discovered that native Phragmites have been almost completely displaced by the invaders, and remnant populations only exist in isolated pockets (in 2007, there were a few left on the Cohansey River in Cumberland County).
Another example is the hart’s-tongue fern, Asplenium scolopendrium, a fern common in Europe but rare in North America. Our native variety, A. scolopendrium var. americanum, survives mainly in New York, Michigan, and Ontario, with small, isolated colonies in places as unexpected as limestone caves in Alabama and Tennessee and even in a lava-tube cave in New Mexico. NatureServe Explorer notes an introduced population in New Jersey, the result of ex-situ conservation plantings begun in the 1930s, and I was thrilled when, a while back, I found some at a local garden center. Unfortunately, genetic studies show that plantings such as those in New Jersey—and any plants offered for sale—derive from European stock, genetically distinct from the American lineage. In some of New York’s native populations, European DNA appears along the margins of some sites, the result of well-intentioned restoration efforts that inadvertently blurred the line between native and introduced forms (See Heo, 2022 or this excellent podcast episode of the Field Guides with hart’s tongue fern expert, NYS conservation biologist Michael Serviss).
A few years back, when I still bought cultivars, I fell victim to this confusion. I purchased a pretty plant labeled “Lance Corporal” Virginia Jumpseed (supposedly Persicaria virginiana) from a garden center. It said native, so of course it was native—right? Plus, it had such pretty red flowers, unlike the more common one with its white flowers. Well, this plant spread all over my yard and acted wildly aggressive, nothing like the well-behaved native. It turns out that whoever labeled that plant should have labeled it Persicaria virginiana var. filiformis, to indicate this was an Asian variety (these days it seems to be considered not just a variety, but its own species, Persicaria filiformis … read more at the Maryland Invasive Species Council). There is absolutely no evidence that this cultivar, apparently developed from a chance seedling at Rowden Gardens, an exotic plant nursery in Devon, England, is native to the US. But it was good marketing, right? I’m still pulling up this plant years later.
As I ponder these examples: native plants mistaken for invasives, invasive strains mistaken for natives, European genetics contaminating American populations—I find myself questioning the use of cultivars altogether. These have been the subject of much debate lately, and we are assured that some cultivars are harmless, that they won’t spread or hybridize with native populations. But do we really know this? How long will they remain harmless? Haven’t we heard such assurances before? The history of botany is littered with confident predictions that proved disastrously wrong. Each time, we’re told this is different, that we understand the risks now. Each time, it turns out we don’t. Perhaps the only honest answer is that we’re running yet another uncontrolled experiment—this time in our own gardens. I’ve decided to tread carefully with cultivars and avoid them when I can. There’s always a better straight-species native around if I hunt a little.
Mistakes are how we learn, but only if we’re willing to admit we made them. My pokeweed error was embarrassing but harmless. Introducing multiflora rose, misidentifying an invasive reed as native for a century, contaminating native hart’s-tongue populations with European genetics in the name of conservation—these mistakes have consequences that can’t be undone. Yet at each step, someone was confident they knew what they were doing. The pattern repeats: we intervene, we assure ourselves we understand the risks, and decades later we discover we were wrong. The introduced strain outcompetes the native. The “harmless” cultivar escapes. The restoration project inadvertently destroys what it meant to save. Perhaps the real lesson isn’t just that we make mistakes, but that we consistently overestimate how much we understand and underestimate how much damage our interventions can cause.
As we head into late fall and our native plants begin their seasonal retreat, I find myself thinking about how these mistakes should guide us forward. Yes, we need humility about what we don’t know. Yes, we should question confident assurances about “harmless” cultivars or “improved” varieties. But the answer isn’t to retreat from the landscape—it’s to engage more thoughtfully. Plant more natives, but true natives. Create more habitat, but with local ecotypes. Do more restoration, but with species we actually understand. And with winter approaching, read more—dive into the scientific literature, explore botanical history, learn the fascinating stories behind our native plants. Don’t think that learning about plants has to be a chore. On the contrary, it can be an absolute delight! And yes, pokeweed is absolutely, definitely a perennial.
With appreciation for your understanding,
Kazys Varnelis, Ph.D.
President, NPSNJ