Some Flowering Trees and Shrubs in Mid-May

A whole lot of white, and a little red right now. Here's fringe tree

and pagoda dogwood

Red buckeye is a small tree that makes a big show here and there on residential streets. I've only seen it growing wild along a back road in the North Carolina coastal plain.

pawpaw hanging promisingly

This fragrant snowbell (Styrax obassia), was planted by Bob Wells behind Veblen House in Herrontown Woods.

And across the street from me, a horse chestnut puts on a dazzling display, with flowering, towering black locusts adding lofty blooms behind.

The Life, Death, and Rebirth of the PHS Ecolab Wetland

On Nov. 6 this past fall, I was returning from a California tour with a latin/jazz band, feeling celebratory. The tour had gone well, but then I received word that something in Princeton had happened that would spoil the return. This is what I found the next morning. The Princeton High School Ecolab wetland had been stripped of vegetation. 

For the past fifteen years, since being converted from turfgrass to native habitat, the wetland has looked like this, packed with more than 30 species of native wildflowers, sedges, rushes, and shrubs like silky dogwood, elderberry, buttonbush, and swamp rose. Though packed with native vegetation, the Ecolab has continued to perform its function of collecting runoff from surrounding roofs and then releasing that water into the town's system of storm drains. Long ago, I learned from experience that native plants thrive in wet, sunny places. The Ecolab is a stellar example. 

Over the years, the magic of this planting has resided not only in the periodic infusions of runoff from the school roof, but also in the sump pump, nicknamed "Old Faithful", which consistently delivered a gift of water from the school's footings into the Ecolab every 20 minutes or so, keeping the wetland wet even through droughts. 

That consistent moisture has sustained frogs and crayfish, and even a very rarely encountered native plant called the marsh marigold. Through those fifteen years, the PHS Ecolab had been Princeton's premier demonstration of how to use water in the landscape before sending it down a pipe to Carnegie Lake. As its name suggests, it has also been used as a teaching tool by the highschool's environmental science teachers.

The project was in-house from the beginning. In 2006, seeing how lawnmowers struggled to cut the grass in this very wet detention basin, I contacted environmental science teacher Tim Anderson and school board member Charlotte Bialek, and together we got permission from the school to create what became known as the Ecolab wetland. High school students designed a series of three ponds for water to flow through on its way through the basin. The grounds crew dug the ponds, and students, teachers, and I dug "littoral" shelves around the edges of the pond, for plants that like to grow near water but not in it. The received important help from a federal agency, Partners for Fish and Wildlife, in shifting from turf to native vegetation, but that help was brief and freely given. 

Over the years, students, teachers, and I have managed the vegetation, keeping out invasive species and discouraging the more aggressive natives like cattails.

In the fall of 2021, Jim Smirk and other environmental science teachers invited me to speak to their students about the wetland's functioning and history. Teachers were excited about expanding the use of the wetland in their curriculum, and converting another detention basin on school grounds to native habitat for study. 

So, what happened? 

How did we end up with a big machine and bare dirt where a wetland had flourished? 

The answer resides deep in the nature of institutions and how they tend to view nature. While the teachers, students, and I were viewing the ecolab wetland's native diversity as a richness and an opportunity, another part of the school--in central administrative offices distant from the high school--was viewing all that lush, complex native growth with a less friendly eye. 

Ask yourself why the lawn continues to dominate our suburban landscapes. For those of us who love nature in all its complexity, a lawn is boring. But for others, nature's complexity is disturbing, confusing, intimidating, and must be fought against. A grounds crew's job is to subdue and simplify nature, not to nurture and work with it. Thus, two very different and opposing narratives about the Ecolab have thrived for more than a decade in different "silos" of the school system.

What finally brought these two opposing views into direct conflict was trees. The Ecolab was originally planted without trees, so as not to pose a threat to surrounding buildings. But at some point, a few willows sprouted on their own and were allowed to grow, on the premise that they would benefit the birds by adding structure to the habitat. When the trees got too big for volunteers to cut down, we asked the facilities department to remove them. Those periodic requests over a number of years, by phone message or email, did not gain a response. It didn't make sense. Here we were maintaining a useful, attractive wetland on school grounds for free. Why couldn't the facilities department help out by removing the trees that had become too large? We grew discouraged.

Though all our work and the teachers' enthusiasm for utilizing the Ecolab for educational purposes were widely known and praised, the counter narrative gained momentum in the school system's distant administrative offices. There, the Ecolab was portrayed as degraded, overgrown, and overrun by invasive species--too much for mere volunteers to care for. Despite awareness that the Ecolab was used for educational purposes, no one invited the teachers and volunteers to participate in decision-making. 

This past summer, unbeknownst to us, a proposal was solicited from an outside landscape contractor who had come highly recommended. In late summer, I caught wind that actions were being considered for the Ecolab, and asked to see the proposal. I submitted a detailed critique, stating that the proposal to give the Ecolab a "reboot" was deeply flawed and lacked a basic understanding of the Ecolab and how it functions. Others gave input as well, about how important the Ecolab is for educating students.

But this last-minute input was not sufficient to break the institutional momentum. The outside contractor was hired, and proceeded to use a disastrous approach. Instead of taking time to learn about the Ecolab's native vegetation and unique functioning, the contractor decided to act first and assess later. Instead of selectively cutting the trees with a chain saw, they brought in a backhoe and other heavy equipment. 

They came on a Saturday, Nov. 5, and by the end of the day, every bit of vegetation had been removed except for two buttonbushes rising incongruously from the bare dirt. Reportedly, not even the high school principal had been given notice. The devastation caught everyone by surprise, even those who had paid the contractor $18,000 for their services. 

For years, the Ecolab has generated a variety of reactions. For those of us who are comfortable with managing a complex planting with more than 30 native species, the Ecolab has been a treasured oasis of natural splendor for students to appreciate and study. For others who prefer the simplicity and clean look of turfgrass, it has been a disturbing presence on an otherwise neatly manicured school grounds. 

Perhaps growing out of that discomfort, attempts were made in the past to falsely blame the Ecolab's vegetation for school flooding. This misdiagnosis proved very costly to the school system. The high school suffered catastrophic flooding twice, causing extensive damage in the basement and requiring replacement on both occasions of the performing arts stage, after flooding warped the wood flooring. The environmental science teacher at the time, Tim Anderson, and I assembled compelling evidence to show that flooding was caused not by foliage in the detention basin but by water surging in towards the school from Walnut Street. So when an outside contractor came in this past November, claiming the Ecolab was full of invasive species and in need of a "reboot," it was just one more misrepresentation of this unique planting. 

Ideally, a traumatic event like this can become a teachable moment. In the months since, the reaching across silos has finally taken place. Apologies have been made to those of us--teachers and volunteers--whose work and knowledge had not been appreciated. 

I and others have been meeting with members of the Operations Committee, teachers, and schoolboard to get the Ecolab back on track. One day, discussing the Ecolab with other volunteers and the school's Public Information Officer, Elizabeth Collier, looking for a positive way forward, an idea came to mind. Why not use the clearing of the wetland as an experiment in regeneration? Though the contractor did some digging, most of the soil is still intact. Much of the diverse native vegetation would likely resprout come spring. Teachers and their students could then witness the rebound of a wetland from dramatic disturbance, and take part in actively managing the vegetation as it rebounds, removing any tree sprouts and other aggressive species, and adding additional natives in bare areas. 

The central administrators seem now to be listening to the environmental science teachers and others of us who are the most knowledgeable about the Ecolab's functioning and have been the most invested in its ongoing care. 

Update - May 2023

The latest I've heard is that the outside contractor will no longer be involved in the Ecolab. Presumably, this means that management of the vegetation will once again be done by the teachers, students, and knowledgeable volunteers. The school's operations department continues work to repair the sump pump that had been supplying the Ecolab for more than a decade with water even during droughts. "Old Faithful" apparently got old, and stopped working a year or two ago.

As hoped, the native vegetation has begun to rebound. First to reemerge were the marsh marigolds, one of which bloomed, surrounded by what still appeared to be lifeless dirt. The poignancy of this bloom brought back memories of James Thurber's The Last Flower, a story about how, after terrible destruction, the last flower on earth became the first of many. Plants play a similar role in the movie Wall-E.

I compiled a list of lessons learned. 

Institutional Silos -- This tale certainly speaks to how conflicting narratives can spring up in different parts of a large institution like a school system.

The Invisibility of Volunteers -- Our work as volunteers over fifteen years to maintain the Ecolab remained essentially invisible to the powers that be. Emails and phone calls were not enough. Until we began showing up at official committee meetings--essentially reaching beyond our silo--we did not exist. 

Devaluing that which is freely given -- In a lifetime of working with nature, I've seen how nature gives freely, and how all that generosity can be taken for granted, and be undervalued in a society that often judges value in monetary terms. Expertise and stewardship, too, can be undervalued if it's local and freely given, without any formal written agreement. 

The false security of hiring professionals -- It is astonishing just how incompetent the professional landscape company proved to be, despite being highly recommended by a highly regarded area environmental nonprofit. I've seen less extreme examples before, in which an outside contractor is brought in with disappointing results. Regardless of professional reputation, they lack the time to gain an intimate understanding of a local site, particularly one with unique qualities like the Ecolab. Unlike local volunteers who care about the school and the community, an outside firm has no "skin in the game" beyond fulfilling a contract. Spending money on professionals brings no guarantee of desired results. 

Managing nature's complexity -- There is an initiative to add additional complex plantings such as food forests to Princeton's highschool and middle school grounds. Having educational plantings on school grounds is convenient for teachers who would otherwise face the logistical challenge and expense of transporting classes to distant locales. A good model for growing complex botanical plantings on school grounds is the Princeton School Gardens Cooperative, which hires quarter time educators/stewards to oversee care of five school vegetable gardens. For this next initiative, it will be important to acknowledge that a grounds crew is typically focused on maintaining simplified landscapes of trees and turf, and that a separate caretaker who understands and cares about nature's complexity is needed for educational plantings. The grounds crew could, however, play a valuable role,  but only in a collaborative way with a skilled caretaker. 

Update - April, 2025

Since the last update, our Friends of Herrontown Woods nonprofit has been hired by the school to collaborate with students to maintain both the Ecolab wetland and the Upper Basin near the tennis courts. 

Paying Homage to a Fallen Tree

Riding my bicycle home from the library on Wiggins a few days ago, I encountered some neighbors across from the cemetery gathered around a tree stump, and stopped to inquire what they were doing. 

They had affixed strands of masking tape to the stump, radiating out from its core, so that each could mark waypoints on the tape as they counted the rings. Far better than my approach to date, which involves counting halfway, losing my place, and then having to start over. 

When people die, we write up an obituary that includes age. When a tree dies--and a lot of trees have been dying in Princeton in recent years--chances are the tree gets chipped up by giant maws and the stump is ground down into sawdust. Passersby may sense something missing, but not know for sure what had been there.

Having long cast shade from its strategic spot southwest of their house, this tree had clearly been loved, enough so that family and friends gathered around to pay homage and track the tree's life back to its beginnings. The tree's life story was all there in the rings. Widely spaced rings showed extraordinarily robust growth in its mid-years, narrowing towards the end as bacterial leaf scorch took its toll on the vitality of this oak and so many other red and pin oaks around town. Consensus put its age close to that of one of the counters, with birth around 1960. 

Update, May 19: I passed by the tree stump yesterday and saw this touching inscription. 

My family, too, lost an oak recently, a red oak that had started life around 1960 and grew up to shade the patio. The house was built in 1960, by the Dubas, who were proud that their name in fact means "oak." One of three red oaks they planted on the property, this one had been in decline for years--probably a combination of bacterial leaf scorch, some heavy pruning by the 17 year cicadas, and some other sort of insect activity underneath the bark. Most of it we split up for firewood, but I saved a 7 foot section of trunk that friends Victorino and Wilbur milled into boards. They've also been milling fallen trees in Herrontown Woods to craft a boardwalk. 

There are many ways to value and pay homage to a fallen tree.

Afterthought: For anyone wishing to help count tree rings, I've been photographing the "faces" of various extraordinary fallen trees in Princeton. We could call the project the "Tree Rings of Princeton". There are 200 year old trees that grew next to Washington Road. And here's a great white oak, the last of several that used to stand along the Veblen House driveway. A neat thing to do would be to print the photo out on a large piece of paper, and then count and study the rings, marking significant years, e.g. when the gypsy moths defoliated Herrontown Woods in the 1970s, or when the Veblens bought the house in 1941, or when the Whiton-Stuarts built the house in 1931. One question is whether the 17 year cicada years would show less growth, given all the pruning that happens after the cicadas lay their eggs in the twigs. It would be a great thing to display in Veblen House.

Forum on Open Space in Princeton This Saturday

The Princeton Public Library and Princeton Future will co-host a forum in the library's Community Room this Saturday, May 13, entitled “Princeton's Open Spaces - Building Equitable Access, Health, and Resilience." The event, running from 9am to noon or 1pm, will begin with a presentation by Princeton's open space manager, Cindy Taylor, followed by short presentations by a number of us deeply involved with the care and acquisition of open space in Princeton, including Trish Shanley, Sophie Glovier, Wendy Mager, Jim Waltman, and myself. A discussion session will follow. 

For more information, check out an article in TapIntoPrinceton. 

Dark Sacred Night--Bringing Back the Night Sky

A most excellent way to spend 16 minutes of your life is to watch Dark Sacred Night, a short documentary calling upon us to collectively bring back the beauty of the night sky. 

Created by area filmmaker Jared Flesher for the Princeton University Department of Sustainability, the film is a portrait of Princeton astrophysicist Gaspar Bakos and his advocacy to reduce the light pollution that denies us a glorious view of the universe. It will make you rethink the lighting outside your home and in your community, and make you wish you could see the Milky Way rather than light pollution when you gaze skyward at night.

I've witnessed Gaspar's advocacy in multiple ways. Earlier this year he helped us ready a friend's telescope for use at Herrontown Woods. He spoke in the library at the film's showing at the Princeton Environmental Film Festival. It was more recently, when he hosted a star party for a hundred-plus people on the lawn of the Institute for Advanced Study, that I began to think of him as an ambassador of the night sky. Using some sort of laser pointer, he directed people's attention to each of the various stars and planets bright enough to be seen. He drew from science and folklore to tell the stories of the night sky. 

By coincidence, Gaspar's work intersects with my family history. My father, also an astronomer, designed the twin Magellan Telescopes atop Las Campanas in northern Chile--the same mountain where Gaspar is currently building a telescope to scan the whole night sky for anything out of the ordinary. 

Though Dark Sacred Night calls on individuals, businesses, governments, and institutions to direct their lighting downward, it will take something more than isolated good deeds to bring back the night sky. As long as there is no consequence to drive change in behavior, the great majority of people will continue to needlessly spill light upwards, because we can. We become victims of our collective freedom to pollute. 

The loss of the night sky is one more instance in which unregulated and largely unintentional collective emission has imposed a tyranny upon us. My question after seeing the movie was, "How do we incentivize frugality?" I'm hardwired for frugality. My parents grew up in the Great Depression, and in some ways that inherited frugality has spurred my creativity, challenging me to do more with less. Astronomy imposes the discipline of frugality, given how faint are the light sources astronomers seek to understand. All the while, humanity wallows in abundance and excess. It is only through frugality--directing outside lighting downward rather than up--that we can regain the opulent beauty of the dark sacred night. 

Wisteria Contained

As a land manager, having fought back many a runaway acre of wisteria in a woods, tangled with and been tripped up by its myriad tanglings, even walked upon the tranpoline-like, crazy quilt its runners can weave above the ground, I can still feel amazement when witnessing a wisteria molded by intention--first at its abundant flowering, and second, that someone has managed to keep its wanderlust in check. 

This house is a couple doors up from Hamilton Ave. on Linden Lane. Similar displays are likely in progress on the front porch of Morven and at Marquand Arboretum. They hearken back to an era when people had the time and interest to tend to their gardens, when gardening was a relationship, and gardens had personalities. My parents had such a garden in Ann Arbor, MI, where I would trim the wisteria growing up their patio trellis. The flowers were pretty, but never reached the magnificence of this display on Linden Lane.

The wisteria in this photo is thankfully in the front yard, along a town street. If the owner ever lost interest in carefully maintaining it, there's no nature preserve nearby for the wisteria to swallow, only the house and the neighbors' yards. Having witnessed and reckoned with the unintended consequences of inattention, I can see both the beauty and the Burmese python-like potential lurking within, its expansionist nature for now contained.

Related posts:

Where Vines Tackle Trees: A wisteria that grew so thick you could walk on its web of runners without touching the ground. 

Another Perilous Embrace--Wisteria and Horse Chestnut: When wisteria gets loose in a neighbor's yard.

Giving a Talk at Bowman's Hill Wildflower Preserve

Bowman's Hill Wildflower Preserve has invited me to give a talk this coming Thursday evening, April 27, at 7pm. They gave our Friends of Herrontown Woods a Land Ethics award this year for Best Community Project, for the Botanical Art Garden we've created. The talk is entitled: "Collaborating with Nature: A Botanical Art Garden Grows at Herrontown Woods."

 
Here's the writeup on the talk, which can be accessed via zoom. Here's a link to register. If you've never been, Bowman's Hill is a fabulous place to see spring wildflowers in April/May.

"Years of institutional neglect had left the first nature preserve in Princeton, NJ, unusable—its trails overgrown, historic buildings boarded up and the parking lot a staging ground for crime. Ten years ago, three volunteers formed a nonprofit, Friends of Herrontown Woods, and began clearing trails and cutting invasive species. When storms blew down a pine grove next to the parking lot, the Friends saw an opportunity to create something special. Without a budget, invasive growth was quelled, paths grew and a forest opening took shape, now home to 150 native plant species. Artists helped combine nature and culture to create a place of whimsy, beauty and discovery. This is a story of persistence, serendipity, incrementalism, combining physical work and intellect to build a community through stewardship. The Barden has become a place to learn about and collaborate with nature—the most generous and creative force of all."

Time To Pull and Pile Garlic Mustard

One of the most rewarding invasive plants to weed out is garlic mustard. Unlike lesser celandine, which must be either sprayed or dug out, garlic mustard is easy to pull and pile. It's also easy to identify, with a strong garlicky smell to the leaves. Early leaves in the spring can even be tasty, which may explain why it was brought to America from Europe, as early nourishment after a long winter. 

If left unpulled, stands of garlic mustard will become denser year by year, releasing toxins into the soil that inhibit the growth of other plants (can you say "allelopathic"?). If you have a patch that feels overwhelming, here's a success story to inspire you. 

It's best of course to nip an early invasion in the bud. In any given year, you'll see two generations of garlic mustard. In the first year of growth, a biennial plant only produces leaves, gathering energy to launch a flowering stem in the second year. I just pull the second year plants, ideally when they first appear in the spring, but usually when they are in bloom and easiest to spot.

Pulling time is in April, extending into May. This first bloom, in the photo, was on April 10, but they're still blooming now. The clusters of white flowers can make weeding feel like an easter egg hunt. Last year, we had a girlscout troop pull garlic mustard that was growing along the edges of the Herrontown Woods parking lot. They got every last one!

That's the strategy, to pull every last one, before the seeds mature and scatter. If this is done year after year, the soil will run out of seeds to sprout. Each year there will be fewer and fewer plants, as the seedbank in the soil becomes exhausted. How many tasks do you know that get easier every time you do them? It's important to get every plant, every year, so the seed bank can't rebound.

Other gratifying aspects of weeding garlic mustard? Each plant is big enough that each pull provides a feeling of solid accomplishment. And the soil is often still soft in April, so the root comes out easily, especially after a heavy rain. I tell people to "grab low, and pull slow." 

What to do with them once they are pulled? Some people stuff them in plastic garbage bags and put them out with the trash, but though that gets rid of the seeds, it also makes more trash. My strategy is to make a pile. Word has it that even if you pull them in the flowering stage, they can still develop mature seeds. So don't just leave the stems scattered around the yard. If you concentrate them in one pile, it doesn't matter if any seeds mature, because the new plants will all be in one spot and easy to pull or smother. It's important to locate the pile where heavy rains won't wash the seeds away from the piles. 

We've been pulling garlic mustard and piling it like this for years around the Veblen House. This year, it took about an hour to get every last one and put them in this small pile, resting on a log, roots drying in the sun. That job's done for the year. It's a rare feeling for a gardener. I don't entirely trust it, and am going to go out again and check, just to make sure.

Protecting Areas of Princeton Not Yet Infested with Lesser Celandine

Each spring I send out an alert about the spread of a hyper-invasive plant called lesser celandine (also called fig buttercup, or Ficaria verna). Through website posts, letters to the editor, and social media like facebook and nextdoor, I've urged people to take action in their yards to prevent lesser celandine from taking over. The latest effort was a writeup in TapIntoPrinceton. 

Some weeds, like dandelions, proliferate only in lawns and gardens and pose no threat to natural areas. But lesser celandine spreads from lawn to garden to nature preserve, growing in sun or shade, lowland or upland. If left to grow, one plant will ultimately multiply to pave the landscape. Pettoranello Gardens, Marquand Park, Rogers Refuge, Mountain Lakes--these are some of the preserves with rampant infestations. As it displaces native flora, this poisonous plant makes our nature preserves less edible for wildlife.

It can be easy to despair, but the good news is that there are many yards, parks and preserves where lesser celandine is just now starting to invade, and could be easily controlled.

This is what lesser celandine looks like when it first moves in to a new area--a dense mound of leaves with a few flowers in late March and early April.

Westminster Choir College's huge lawn has only five or six of these clumps. It could easily be treated with a little spritz of weed killer (see below for some of the rationale for using herbicide). Five minutes of strategic intervention, and one's work would be done until following up with the same monitoring and treatment next year. 

Here's a sprinkling of just a few plants in Smoyer Park, all in a line, demonstrating how the weed is spread by rainwater that runs along the bottom of this detention basin. Again, this is a very quick job with minimal use of herbicide, with even less needed the following year. 

Here's a big clump next to the school garden at Community Park elementary. If they wanted to be organic about it, they could try covering it with cardboard and thick mulch for two growing seasons and hope the roots die off. Or they could dig it up very carefully and thoroughly, and throw all the plants and associated dirt in the trash.

But that doesn't deal with the clumps of lesser celandine that have spread to the CP lawn nearby. You can't dig up or mulch a lawn, and other alternatives to standard herbicides have not been proven to kill the roots, so you pretty much have to spot spray the lawn with weed killer, or else allow a poisonous plant to take over the very school grounds that a town-wide initiative is seeking to make more edible.

There's a similar dilemma at tiny Barbara Boggs Sigmund Park, where a patch of lesser celandine is spreading across the lawn for lack of strategic intervention. If not treated, that patch will begin to spread downhill, infesting neighbors' yards. 

It's common for one neighbor to let an early invasion expand, unaware of what's going on. This patch is at the back of a property that the owner seldom visits.

Here's another patch spilling under the fence and out towards the street from an infested backyard. This is the only infestation on this particular block, and could be prevented from spreading.

I told the caretaker at Nassau Arms apartment buildings about an early invasion on that property, and he promptly dug it up. Hopefully the diggings went into the trash so that they don't spread elsewhere. We'll have to wait until next year to see how effective it is, but at least there was a quick response. 

What the dramatic and largely hopeless invasions at Pettoranello Gardens and elsewhere can teach us is to treasure and protect those parts of town that can still be spared. To make such protection time- and cost-effective, we must begin by reassessing our blanket condemnation of herbicides as poisons. We don't condemn all medicines as poisons, but instead manage their varied toxicities by applying them selectively and minimizing dose. The same applies to managing a park or one's yard. 

The pandemic dramatically taught us that what each of us does, intentionally or not, affects others. The lesser celandine in one yard or park can easily spread to neighboring areas. This is both humbling and empowering. It tells us that what we do matters beyond the borders of our lives and our yards. Strategic action by the town,  businesses, and residents can stop these infestations while they're still easy to stop. 

Reading the Landscape Along the Towpath -- Early Spring

One place that gets a lot more interesting if you know plants is the towpath along the Delaware and Raritan Canal. For those into reading the landscape, the section just upstream of Harrison Street in Princeton makes for a good read, packed with history, beauty, poignancy, and the drama of invasion. 

First, there's the water, here with branches of elderberry reaching out over the canal in the foreground. Elderberry characteristically sprouts leaves earlier than other native shrubs. Water teaches the richness that reflection can bring to life. 

Along this stretch of towpath, the strip of land between the canal and Carnegie Lake widens, making enough room for a nature trail loop that for nearly 20 years has given hikers and joggers relief from the linearity of the towpath. Part of my life has been dedicated to making interesting destinations along very long trails, whether in Durham, NC or in Princeton. With a hardwired devotion to things, I've been an advocate for this little nature trail, and the unique, savanna-like habitat it winds through, since it was created nearly 20 years ago. Periodically stopping by to check that the trail hasn't been blocked by fallen trees, reading the landscape as I go, I always come away with a mix of joy, gratitude, and grief. 

Some flowers encountered during this walk are native, like this red maple reaching out over the trail.

Then there are some non-native species that fortunately aren't invasive, and speak to past intention. These photos were taken a week ago, when the ornamental cherries were just starting to pop. 

These really old ornamental cherry trees are reminiscent of those planted along the Potomac River in Washington, D.C. long ago. The cherry trees and the yellow spray of forsythia off in the distance show that this seemingly wild stretch of the towpath is actually populated with botanical remnants of another era, back when the university installed these plantings as an ornamental entryway to the campus. 

Adding to the evidence of past caretaking is a derelict row of winter honeysuckle (Lonicera fragrantissima), with very small, very early, and very fragrant flowers. Though it's included on invasive species lists, I've never seen it spread. 

If you're an environmental advocate at a local level, a walk can become a review of past successes and failures. For years, the DR Canal State Park, of which this ribbon of land is a part, would keep this nature loop mowed, but then their maintenance budgets started getting cut. Around the time one of their longtime mowing crew members died, they decided to turn mowing over to the landowners--Princeton University. That handoff happened at an administrative level, but not on the ground. After trying in vain to get the university to take care of the trail loop, I finally contacted Shana Weber at the PU sustainability office. Thankfully, she was able to reach the right people, and the trail is now being kept open. 

But one bit of mowing that the state parks people used to do has yet to be picked up by the university. And here's where the landscape's story shifts from joy and gratitude to grief. The nature trail loop winds through what for many years has been a savanna-like landscape of scattered trees and fields. Scattered trees allow enough sunlight to reach the ground to power a rich understory of wildflowers and shrubs. But due to a lack of annual mowing, that special landscape of forest openings, seldom found elsewhere, is being lost. Here is a forest opening that has become a layer cake of invasive plants, with multiflora rose blanketed by a web of super-aggressive porcelainberry vine. 

Other invasive vines also run rampant, like this Japanese honeysuckle smothering a branch.

Why is no one cutting the oriental bittersweet at the base of this tree, the wild gardener in me asks.

Many of the trees were planted, then ultimately abandoned, leaving a kind of derelict arboretum.

Some trees have succumbed altogether to introduced insects or disease, most commonly Emerald ash borer or bacterial leaf scorch. 

On the ground, the uber-invasive lesser celandine is laying a claim that will surely expand. 

Without annual mowing to sustain the forest openings, a tortured form of succession is underway, with sweetgum saplings being mobbed by the invasive vines. Annual mowing would sustain the special forest openings and reduce the smothering invasives.

A couple places where the native species are doing well are, not surprisingly, in standing water. Here's a rosette of a very healthy rose mallow hibiscus (Hibiscus moscheutos), its feet very much in water.

Here's a shrub that also flourishes in standing water, buttonbush (Cephalanthus occidentalis). 

There are lots of native plants that can thrive in floodplain habitats along the canal. If the university ever gets interested in habitat restoration, this would be a great place to start. It would be a high-visibility demonstration, to be witnessed by all the hikers, bicyclists, and joggers passing by, who currently see not the history and the ecological drama but just another stretch of green.