Native Plants Prosper in a Wet Meadow at Smoyer Park

A little video tour of a wet meadow habitat in Smoyer Park, Princeton, where lots of native wildflowers were planted and early intervention has kept invasive species from taking over. Part of my work at Herrontown Woods. 

 

 

The town helps out by mowing this basin once a year in late winter, and its deer culling program reduces the browsing pressure on the native plants so that many can bloom. This year, 2024, the basin was accidentally mowed in early June. Though traumatic at the time, the plants grew back, and the effect was to concentrate blooms later in the season. 

The detention basin was converted in 2016 from turf to native grasses and wildflowers by Partners for Fish and Wildlife. Ongoing followup by Friends of Herrontown Woods has added additional native species and prevented invasive species like mugwort, Sericea lespedeza, crown vetch and Canada thistle from taking over. Other aggressive plants that need to be countered are giant foxtail, stiltgrass, carpgrass, nut sedge, wineberry, blackberry, and pilewort. Native species being encouraged are big bluestem, Indian grass, various sedges, rose mallow hibiscus, ironweed, blue vervain, partridge pea, black-eyed susan, late flowering thoroughwort, boneset, monkey flower, buttonbush, and some goldenrods.

Botanical Threats to Greenway Meadows--Neighbors Raise Concerns

Over the years I've sung the praises of Greenway Meadows, the park in western Princeton with an asphalt trail running down the middle of an expansive meadow. One post describes the beauty of broomsedge and cross country racers "testing inner nature in a natural setting." Another describes the exhilaration of riding a bike through the meadow on the way to an art exhibit opening at the Johnson Education Center.

More recent visits to Greenway Meadows have focused on the threats to the park posed by invasive species, and the need to act quickly, before the problem gets overwhelming. This past April, it was dramatic to see how lesser celandine is beginning to invade the meadow and the lawn.

Then this summer, Mimi Schwartz, who lives near Greenway Meadows, reached out about the park. She had noticed some attrition among trees along the Poetry Trail, and wondered if competition from the tangle of invasive shrubs growing beneath them might be a cause.

Another neighbor of the park, Jennifer Widner, is focusing on threats to the meadow--threats that surely go unnoticed by the many people who walk or jog down the asphalt trail, see a pleasing green, and look no closer.

Still apparent to all are the many native wildflowers in the field, among them common milkweed and wild bergamot. 

But on a visit to meet Jennifer, I was astonished to see the extent to which Sericea lespedeza (aka Chinese bushclover, Lespedeza cuneata) is beginning to dominate. This is an invasive species that has become a big problem in the southeast U.S. and the plains states, but was comfortingly rare in Princeton when I first moved here in 2003.

There are various species of native bushclover that can sometimes be found mingling with other wildflowers in a field, but Sericea lespedeza doesn't, as they say, "play well with others." It's behavior is more that of a bully.

In understanding the threat posed, it helps to have lived elsewhere in the country where Sericea lespedeza has had a longer track record of aggression. Living in Durham, North Carolina, near where the species was first introduced, in 1896, and is still widely used for erosion control despite many efforts to have it banned from seed mixes, I witnessed its capacity to displace native species. 

For those who say live and let live, and let it be, consider the ecological consequences if the meadow ultimately becomes a monoculture of an introduced plant with indigestible seeds and inedible foliage. Here's one fact sheet's description:

"Sericea contains a high concentration of tannic acid, which causes wild and domestic animals to avoid eating it, unless no other food is available. Animals then forage more intensely on native plants, which depletes the desirables and allows invasives to increase. Tannic acid leaches from sericea into surrounding soil, creating a toxic environment that prevents or slows the growth of other plants, giving it yet one more advantage."

Mimi and Jennifer have had some success engaging public officials on these threats, and the land managers at DR Greenway's headquarters nearby are potential allies. 

The project with the clearest solution is the freeing of trees from the invasive shrubs growing beneath. A greater challenge, requiring intervention and vigilance for years to come, will be stopping uber-invasives like lesser celandine and Sericea lespedeza. 

My experience, though, is that the work can get easier year to year, as steady effort makes the invasives less numerous. Down the road, or down the trail, as the threat recedes, those involved may get to experience that wonderful "walk in the park" feeling, where the botanical bullies have been sent packing, and require only a bit of ongoing vigilance and mild intervention to prevent their return.

For more information on Sericea lespedeza, try these: BlueRidge and Oklahoma State.

Related post:

Monocultures in the Making - 2013

The Lost Forest of Rogers Refuge

This past November, I received a request to look at a lost forest in Princeton. 

The request came from what may be the oldest open space organization in town--the Friends of Rogers Refuge. Dating back to 1967, FORR has been working with the town, and the water company that owns the land just down from the Institute Woods, to sustain the refuge's role as premier habitat for a tremendous diversity of birds.

Over the years, I've been able to witness and collaborate with a progression of leaders who have overseen stewardship--the Southerlands, Tom Poole, the Spars, the Varians, and most recently David Padulo. 

At annual meetings, discussions have tended to focus on the refuge's central feature, the surprisingly extensive marsh--how to keep it wet enough and protect it from the super-aggressive Phragmitis.

But this year, concern now extends to the floodplain woodlands surrounding the marsh--also vital bird habitat. One of these woodlands, thriving four years ago, has lost its trees.

This was not a forest classically lost to logging. The trees were not cut down but rather strangled over the course of several years, then left standing, each tree a monument to its past life. 

Few have seen the now ubiquitous strangler, the Emerald Ash Borer accidentally introduced to the U.S. from Asia. It's larvae work quietly under cover of bark, feasting on the ash trees' circulatory tissues. 

That a whole forest could die speaks to how common ash trees once were. The most numerous tree in Princeton up until just a few years ago, comprising more than 10% of the tree cover, the ash tree's skeletons can be found throughout the canopy of residential and open space lands. Ash were particularly good at colonizing abandoned fields, to the point of dominating one area of what is now Rogers Refuge. 

As the botanist in an organization of birders, I was asked what the longterm prognosis for this lost forest might be. Winnie Spar, Joe Melton, and I walked the red trail to have a look.

One striking feature is what I call "poison ivy trees." These are dead trees, still standing, that have been scaled by poison ivy vines, with their classic "hairy is scary" stems. In order to bloom, poison ivy must climb a tree, sending out lateral flowering shoots along the way. The branch-like laterals give the tree the look of still being alive, even though all the leaves are now poison ivy. The flowers produce berries that, birders will enthusiastically tell you, serve as important food for birds.

Another feature of a lost forest is the shrub growth that now thrives on the infusion of sunlight previously claimed by the tree canopy. Much of this shrub growth, unfortunately, is nonnative and inedible to wildlife, like this Asian Photinia. At least it can be said that the invasive shrubs are not as thick at Rogers Refuge as they are at the Institute Woods just up the hill.

A few other native tree species fill a small portion of the void. In early November, the occasional silver maple and pin oak still had many of their leaves. Mixed in were a couple elms, and a red maple. 

Used to the numerous red maples at Herrontown Woods on the other side of town, I was surprised to find instead an abundance of box elder of every size growing in this broad floodplain of the Refuge. Related to maples, box elder are not the most statuesque of trees, but their soft wood can make good bird habitat. They now stand as the main hope for rebound in this patch of former forest. 

The walk being with such knowledgeable birders, attention never strayed far from bird life. We saw a couple pileated woodpeckers, a coopers hawk and a couple other larger hawks. Winnie kept up a running monologue about the status of this or that bird. Mockingbirds have been around for a long time, but the catbirds keep them out of their territories when they are present. While a warming climate is causing many birds to extend their ranges northward, ravens, surprisingly, are moving south. She's seen some in the Refuge. Warblers love something about the spicebush flowers, whether it's the flowers themselves or an insect in them. Blue gray knatcatchers were mentioned, along with many other bird names that didn't register in my botanical brain.

There's a lot of concern that last year's fires in Canada have been very hard on migrating birds that nest up there. A woman who catches and tags migrant birds had been having very few birds coming back down from Canada, but her catch/tag/release activity, conducted on Sundays, was hampered by rains every weekend this fall. One day she got only ten birds, total. 

But then Winnie is quick to add that she saw Cape May Warblers in the Refuge for the first time, several in fact, with immatures, and they too nest in Canada. Winnie is one to accent the positive, while acknowledging that migrant bird numbers are down 50-90%. 

This lost forest, the decline in bird numbers, accelerating changes in climate, democracy under threat--in many ways, America is losing its memory of what it once was. The soil, for its part, holds memory through the seeds that remain dormant within it. Back when the seed bank--this stockpile of seeds yet to sprout--was dominated by the seeds of native species, succession as an ecological phenomenon featured an orderly and predictable progression of species, from grassland to shrubland to mature forest. But the soil under our feet has lost its memory, whether by plow, development, intense browsing, or displacement of native species. Invasive lesser celandine, poisonous to wildlife, coats the ground in the spring, followed by inedible stiltgrass and its billions of seeds in late summer. Invasive shrubs and deer combine to limit native species and thwart the once timeless process of succession. Though the tree canopy is still dominated by natives, these are under increasing attack from introduced insects and disease.

Even healthy trees can be overwhelmed by vines of porcelainberry and wisteria.

Given the circumstances, it's fair to ask what sense there is in persevering. What I find is that the native growth force, if often smothered and badly abused, remains intact. When given a chance to prosper, native plants and wildlife still can thrive. In Rogers Refuge, we've seen a tremendous rebound of spicebush since the town began culling deer to reduce browsing pressure. That in turn has improved habitat for birds. FORR has paid contractors to successfully set back the Phragmitis and porcelainberry. 

Through periodic interventions over a number of years, the Varians have virtually eliminated the one patch of invasive Japanese knotweed at Rogers Refuge. 

We pick our spots, time our interventions strategically to have the most impact for the least amount of effort, and look for opportunities. Despite the tragedy of losing ash trees, the new openings in the canopy could potentially allow native shrubs to grow, flower and bear in ways they haven't since being shaded out decades ago. 

Our inherited environmental mindset is that nature, if protected from intentional depredations like logging and draining, will heal itself. As FORR's webmaster Laurie Larson points out, "when Charles H. Rogers and the Southerlands started birding the “Water Company” in the 60s and 70s it was a landfill." The initial fight was to put an end to dumping. But now, at Rogers Refuge and many other places, the main depredations (invasive species, climate change) are unintentional, and the healing must be helped along by intentional effort. That effort could seem a sacrifice, but the primary feeling is one of gratitude, for the chance to work with nature--the greatest and most generously creative collaborator of all. 

Leaves and People Win in Princeton Parks

You could say this is just a photo of a local park with a lawn and a couple trees, but that would be missing the big picture. What we have here is a win-win-win-win. Now, I've always wondered why win-wins, not to mention win-win-win-wins, don't get people more excited. Anyone interested in making the world a better place knows that, given what a fix the world is in, and how busy people tend to be, if we just get one win at a time there's no way we'll ever reach our goal in time to kick back and enjoy a nice cool drink on the veranda. With all the forces conspiring to make the world a worse place, we need wins in big batches--twos, threes, as many as we can get.

So, please, show a little excitement when I point out all the wins in this photo. They all have to do with those magical things called leaves. For twelve years, I've watched those white oaks grow, each year extending their branches to offer more shade for the picnic tables beneath them. As if calibrated to the shade, birthday parties seem to grow in size and frequency each year, centered under the trees and radiating out across the park. Clustered there next to the sandbox, they are the right trees in the right place, and whoever planted them should be given an award for creating an oasis of beauty and comfort where people can come together.

But what to do with those leaves when they fall, albeit very slowly through the winter, being oaks. That's where the other wins reside, for there was a time when the town would swoop in with a big crew and a big truck, then spend most of the day blowing the leaves into a pile, muscling them into the truck, and hauling them out of town to the compost center. Nice compost, you might think, but at what expense? There's the man-hours spent, the truck to buy and maintain, the extra time to drive out of town, the export of nutrients from the park, and all the while, greenhouse gases being scattered to the winds to further trouble the earth.

A few years ago, seeing all these negative impacts on budget, park and planet, I asked the parks director if the town (okay, "municipality") could return to the old borough approach of simply mowing the leaves back into the lawn. That way, the parks department would be modeling what its environmental commission has been recommending all along, that people utilize their leaves rather than blow them to the curb.

What a joy, then, to see that this year the parks department has adopted this approach in Potts Park and elsewhere. In this photo, you can see the mulch-mowed leaves nestled between the grass blades, where they will decompose, feed the lawn, reduce runoff, and maybe even make the ground a little softer when kids fall. There's a brown tint to the lawn, but that will quickly transition back to green.

This far into the blogpost, I've lost count on how many wins this simple change in lawncare has achieved, and the tally wouldn't even include all those lower priority tasks the parks crews will now have time to do. So, grab a mower or fashion a leaf corral, and see how many wins you can gather in your own yard, and later, while sitting on the veranda, make a toast to a better world.

Gulick Park: It Takes a Fantasy Village

The stereotype is that "kids these days" tend to stay indoors, discouraged from outdoor adventure in part by woods that have become impenetrable thickets of thorny invasive shrubs. A striking counter-story to that stereotype played out in Princeton's Gulick Park this past summer. Some of Princeton's open space has very little native plantlife on the forest floor, due to past plowing. In areas where the invasive shrubs haven't filled the void, the combination of trees, sticks and empty ground can make an appealing canvas for the imagination--essentially a natural playground for kids. Some schools, such as the Willow School in Gladstone, NJ, and the Princeton Friends School, incorporate natural playgrounds into their campuses. Attendees of the Princeton Environmental Film Festival will remember a wonderful documentary called School's Out about a completely outdoor kindergarten in Switzerland. Princeton's evergreen forest in Community Park North, planted back in the 1960s, was a natural playground until most of the trees blew down during Hurricane Sandy.

My first inkling that not all kids were spending the summer huddled in front of computers and lounging on sofas with cell phones came when biking through Smoyer Park. There, in the open woods near Snowden Lane and Van Dyke was a shelter carefully constructed out of sticks. The workmanship, or workpersonship, was impressive.

Weeks later, during a nature walk I led through Herrontown Woods, the leader of the informal Friends of Gulick Preserve, Ed Simon, told me of a whole village constructed there by teenage girls. He mentioned Narnia as a possible inspiration. (Update: Though mentions of Narnia are being left in the post, the actual inspiration for this village was other books. See comment below, sent by one of the daughter's parents.)

Here's what I found on a recent visit. There were promising signs of construction along the main drag, a broad trail that extends into the woods from a little deadend fragment of Terhune Rd near Dodds Lane.

Those lean-to structures are mere prelude to the village further in. Small abodes fashioned of sticks and yarn--shall we call it Yarnia?--stretch along leafy trails that hint at a matrix of streets. Might the streets have names, and if so, would they be like Princeton's tree streets, except that Sweetgum Lane would actually have sweetgums growing along it? Or would the streets have far more fanciful names from some other world entered only through the imagination?

This one reminds me of a shelter that some friends and I made deep in the woods when we were kids. The project ended when my face broke out in a poison ivy rash from digging roots out of the ground to make a nice floor. Poison ivy roots have the same oil as the leaves, apparently. The rash gave me Nixon-like jowls for a week. Still, it's a very positive memory.

At times like this, it would have been helpful to have read fantasy fiction, to better understand whether these pebbles are a literary quote or, perhaps, some sort of currency for use in transactions with other forest dwellers, with protective netting to keep the Rock Doves from stealing them.



A bit of speculation here, that the village's proximity to Gulick Preserve's pond is not coincidence. Wikipedia tells of the Wood between the Worlds, "a pond-filled forest in The Magician's Nephew (1955), the sixth book in The Chronicles of Narnia by C. S. Lewis. Each pond is a portal that provides instant transportation to a "world" such as ours and Narnia's."

The kids must have been surprised, one fateful day in early September, to step into the pond and be instantly transported to school.

Hidden Nature and Drama at Quarry Park

It doesn't look like much of a nature trail, this paved walkway that makes a broad circle around the perimeter of Quarry Park.

But what's this? On one recent visit, it was clear some youthful imaginations had turned this peaceful park into something far more dramatic. There was evidence of defenses assembled against attack, Swiss Family Robinson-style. A wall of sticks had been constructed across the trail, to slow any invaders, and caches of ammunition the size of small cannonballs stashed here and there. It took me back to my own childhood landscape, stashing horse chestnuts in strategic spots for later use. I don't remember any actual attacks, but the preparations were serious business.

A stump and a clearing near Spruce Circle are the legacy of another bit of drama, when powerful winds swept through a few years ago, knocking down a grove of trees.

One of the resprouts, a black locust, bears thorns that may once have provided vital defense, but now seem, like the kids' defenses, to be aimed at imaginary foes.

Head down the path at the lower end of the park, and the plain lawn yields to some diversity. Here's a smooth sumac,

and a white pine dropping its older needles.

It's been a good year for white snakeroot, whose scientific name was recently changed from Eupatorium rugosum to Ageratina altissima, apparently to vex botanists who commit scientific names to memory. The plant is common in part because it is toxic, discouraging the deer.

Japanese knotweed can form dense, exclusionary masses along the banks of the StonyBrook elsewhere in Princeton, but on this upland soil in the shade it seems benign,

with attractive seed structures.

Sure enough, growing in the midst of a default thicket of honeysuckle shrubs at the bottom of the park, one osage orange tree, bearing not oranges but these curious green balls, which may once have been dispersed by megafauna, but now clearly get around thanks to kids. The tree has a rich history, with remarkably dense and rot-resistant wood used for bows and fenceposts.

What a Little Dew Can Do

Here's a bit of serendipity. Shadows play upon the grounds of Princeton Battlefield, charmed with dew on a Saturday morning.

Ever the resident tourist, a shadow selfie with Mercer Oak II. Had no luck getting the shadow to smile.

Sorry, but you can't look at any screen--TV or computer--without at least one obligatory car commercial popping up. The sound track runs something like, "If George Washington were alive today, ...", though he might eschew fossil fuel altogether and stick with a horse. Those founding fathers thought about long term consequence. What ever happened to that kind of thinking?

The original motivation for stopping during a drive by of the Battlefield was documentation, not aesthetics: to photograph the invasive porcelainberry overgrowing flowering dogwoods planted as part of the nation's bicentennial celebrations in 1976.

One of my recurrent cause celebres is to save the Dogwood Garden Club's dogwood legacy from the aggressive vine growth. From the green/yellow of the porcelainberry vines crawling over the red leaves of the dogwoods, you can see who won this year's skirmish. The Dogwood Garden Club doesn't know who I am, and for all I know they've forgotten that they ever planted these trees along the field's edge in the first place.

There was also an obligatory photo of the great disappearing bamboo patch. Two years ago, this was a thick clone of bamboo growing out over the path down to the Quaker Meeting House, but a series of well-timed cuttings with magic loppers over the past couple years have sapped vigor from the bamboo's giant root system. The decisive strategic intervention came this past June, when Kip Cherry and I cut down the regrowth from a cutting in the spring. It was some inconvenient toil, but deprived of any payback from that big investment in regrowth--two years in a row--the bamboo has nearly given up. A visit next spring should be light work, followed by a refreshing beverage on the Clark House porch.

Dew was also working some magic on the vista on Quaker Road near the towpath. Scattered pin oaks in a field of goldenrods.

Thanks goes to my daughter Anna for getting me out that way early on a Saturday, to drop her off for a busride to Philadelphia to do some canvassing. Otherwise, that encounter with morning dew would have never happened. Finally, a reason to be thankful for this election season.