July Nature Sightings in Herrontown Woods

Here are some images lingering in my mind and camera from days spent in the field in Herrontown Woods in July.

When the sun briefly shines through the canopy, illuminating life beneath the water's surface, you can look closely and see that one of these tadpoles is turning into a frog. Recent rains have kept the little vernal pool along the red trail well watered. 

Here's a very tall victory for habitat restoration. Towering over our land steward Ninfa is a Tall Meadowrue, living up and up to its name, topped by a cloud of subtle white flowers. This part of the preserve previously was dominated by a massive three acre clone of tree-tackling wisteria that we have been steadily subduing. 

The miniature flowers attract miniature bees--an oasis of tininess in our big big world.

Always a surprise to happen upon a box turtle hidden in the grass. Can anyone decode those hieroglyphics on its back.

The delight of happening upon a box turtle would not have been had if I hadn't been out there clipping off the hundreds of wisteria sprouts that still rise from the clone's massive root structure. Consistent cutting and treating of these shoots, which once climbed seventy feet into the canopy, will ultimately exhaust the wisteria's  sprawling root system. 

In the Barden, the bottlebrush buckeye flowers have been attracting a sphinx moth that looks and flies like a miniature hummingbird. It shifts from one flower to the next, probing for nectar with extraordinary precision.

Butterfly numbers have been down, but there was the pleasure of counting seven on a large buttonbush shrub in a raingarden uphill of Veblen House. By corralling runoff before it reaches the house, the raingarden feeds pollinator plants while keeping the basement dry.

If you have a garden, you may have some weed grasses that look like these: giant foxtail and barnyard grass. Pull them out before their seeds mature.

Some weeks ago, a mysterious "crack!" was heard near the Veblen garage. A minute later, another crack, then another. What was going on? Where was the sound coming from? Then a big red oak began to tilt slightly, then some more, until "SNAP!", the trunk broke off some six feet up from the ground, and the tree crashed down into the circular stone horse run. Why would a healthy looking, 100 foot tall tree topple over on a windless day? 

These curious bits of sawdust, noticed a few days later, surely provide a clue. Could Ambrosia beetles do this to a tree?

Less unexpected are the puffballs that rise in front of Veblen House this time of year.

Year-End Update on Herrontown Woods - 2025

If you appreciate this blog, one way to give back is to support the work of the Friends of Herrontown Woods (FOHW), the nonprofit that we founded in 2013 to make the preserve usable again after long neglect. Our group now manages trails and habitat on 230 acres of municipally owned land in Princeton, and rely on donor support to pay our expenses. It's been a great year, and I'd like to share some of our accomplishments. Each donation provides support and inspiration for our work to restore habitat and history at Princeton's first nature preserve.

GOOD NEWS FOR PRINCETON'S SALAMANDERS

Herrontown Woods' large size, clean water, and wet terrain make it a haven for amphibians. The Princeton Salamander Crossing Brigade, founded by FOHW board member Inge Regan, is in its third year of helping hundreds of salamanders and frogs safely cross the road during their spring migration. 30 participants include experts and beginners, Princeton High School students and faculty, professors and community volunteers. A lively dialogue via whatsapp continues yearround. 2026 will mark a breakthrough, as Princeton municipality has agreed to close the road during the rainy nights in early spring when the amphibians are on the move. The initiative was written up in the Town Topics, TapIntoPrinceton, and the Daily Princetonian.

THE BOTANICAL ART GARDEN ("BARDEN")

Visitors to Herrontown Woods often describe it as "magical" and "unique." The award-winning Barden contributes a lot to that impression, having evolved since 2017 through a merging of many talents and visions. We keep adding native plants--some 160 species thus far--and have done surprisingly well at catching the weeds before they can spread. Kids love the charismatic wood frogs in the spring and the green frogs that take up residence in the summer. On the first Sunday morning of each month, we host a May's Cafe next to the gazebo, with coffee, tea, and baked treats. 

SURPRISING SUCCESS WITH INVASIVE SPECIES

People are used to bad news about invasive species, but by being proactive we have largely vanquished many kinds of invasive plants that plague other preserves. In particular, through early detection and rapid response, we continue to protect Herrontown Woods and Autumn Hill Reservation from the uber-invasive lesser celandine. We also saved many trees by slaying a giant "wisteria monster" around Veblen House, and more recently have subdued another, nearly 3 acres in size, over near the main parking lot. Timely intervention is also protecting the preserves from Japanese angelica tree, bush honeysuckle, jetbead, porcelainberry, garlic mustard, mugwort, Chinese bushclover, and a new invasive shrub/tree so little known that it lacks a clear name. Late summer intervention is helping limit the spread of stiltgrass. All of this has been achieved through steady, incremental effort year after year by our volunteers and paid interns.

A COMBACK STORY FOR NATIVE SHRUBS

Native shrubs have a hard time of it in Princeton preserves. The combination of deep shade, deer browsing, and competition from invasive species has caused many types of native shrubs to literally lay low. The town's deer management program has helped, but pinxter azaleas, Hearts a' Bustin', and shadbush in Herrontown Woods still persist only in miniature, unable to flower. By transplanting some of these to sunnier spots in the Botanical Art Garden and caging them to protect them from deer, we are showing the public a beauty and vitality that had previously been suppressed. We're giving other native shrubs the sunlight and protection they need as well: alternate-leaved dogwood, silky dogwood, elderberry, buttonbush, and swamp rose.

A FLOURISHING WET MEADOW

Another successful FOHW project is managing the wet meadow at nearby Smoyer Park. Fed by runoff from the parking lot, it's actually a lowly detention basin converted by Partners for Fish and Wildlife long ago to native meadow through our initiative. Girl scouts had fun adding wildflower seed collected locally. A meadow is vulnerable to takeover by invasive plants like mugwort, Chinese bushclover, Canada thistle, and crown vetch, but strategically timed work each year to discourage those species has paid off. Each year the work has gotten easier as the weeds become fewer and fewer. Natives flourish if given a chance.

MAINTAINING AND IMPROVING TRAILS

FOHW was able to coordinate rapid response to clear trails and grounds after major storms this year. Winter is actually a great time to scope out routes for new trails. This year, we created a Black/White trail--to serve as an intro to Herrontown Woods for those entering the preserve from Princeton Community Village--and extended the Blue Trail down through the  "Valley of the Giants," where there are some particularly large tulip trees and oaks. Over the past three years, we've also been shifting some trails at Autumn Hill Reservation to drier, more open ground. Meanwhile, the long, locally sourced boardwalk extending from the main parking lot up to Veblen House has been getting rave reviews. We call it the Voulevarde, because it was crafted by chainsaw virtuoso Victorino, and leads to Veblen House.

NATURE WALKS

In addition to periodic nature walks by Steve Hiltner, Sarah Roberts, and others, FOHW offered forest bathing walks this year, led by Rich Collins of the Friendly Territory. Steve continued to lead walks through the Princeton Adult School on Herrontown history, ecology, and geology.

EVENTS

Along with our ongoing traditions of hosting the Lunar New Year, Earthday, the Veblen Birthday Bash, and other events, we had for the first time dancing, as part of a festive performance of Celtic and folk music by the Chivalrous Crickets.

COMMUNITY OUTREACH

FOHW is in its second year of collaboration with Princeton High School, providing expertise and mentoring as we work with Jim Smirk's environmental science students to manage two detention basins for native diversity. Students learn ecological analysis techniques while doing hands on work to weed out invasive plants. These wetlands conveniently provide complex native habitats on school grounds for study. Focus in 2026 will be restoring ecological health to one of the basins, the Ecolab Wetland, which was disrupted by necessary infrastructure repairs completed earlier this year.

GARDENING CLASSES AT MAY'S GARDEN

May's Garden--the restored and now expanded fenced-in garden site where Elizabeth Veblen once grew her vegetables and flowers--completed its third year under the inspiring leadership of master gardener Mathilde Burlion. Assisted by Andrew Thornton, Mathilde led many Grow Little Gardener workshops for young families. 

HERRONTOWN WOODS COMMUNITY COLLAGE

Conceived by artist and board member Hope Van Cleaf, the Herrontown Woods Community Collage is modeled after the mural in the Princeton Public Library. Hope has been conducting workshops in the Barden and elsewhere, with each participant contributing their artistry. The individually created tiles will be brought together on a wall in 2026 at Veblen House. 

SPRUCING UP VEBLEN HOUSE AND COTTAGE

New board members Ben Schaffer and Derek Reamy have been instrumental in organizing and sprucing up the buildings and grounds, and adding momentum to renovations. 

AN INSIDE-OUT MUSEUM

The windows and walls of the House and Cottage are being used to tell the many stories of the buildings and the fascinating people who called them home. The story of the Veblens' extraordinary lives and contributions were the first installation. To be added are the stories of the Whiton-Stuarts--the original owners who sold the house to the Veblens in 1941--and the small-holder farmers who built the 1875 farm cottage. Much research has been published at VeblenHouse.org.

COLLABORATIONS WITH PRINCETON UNIVERSITY 

Visits by Princeton University students noticeably increased in 2025. Ecology professor Andy Dobson again brought his popular undergraduate ecology class to Herrontown Woods for a tour.  Graduate students from the Princeton School of Public and International Affairs offered spirited help during workdays. Members of the university's Princeton Birding Society led our Backyard Birdcount. We also hosted visits and workdays through Outdoor Action for incoming freshmen.

STEWARDSHIP INTERNS

FOHW is grateful to Green Matters for having funded summer internships in 2024 and '25. Interns Ninfa and Moss worked through the summer, keeping trails clear, cutting invasive species, and helping with events. Moss headed back to college in the fall, while Ninfa will continue to work part-time at Herrontown Woods through the winter.

GRATITUDE YOGA

We are also very grateful to Gemma Ferrell for continuing to conduct her popular Saturday morning Gratitude Yoga classes during the summer and fall on the grounds next to Veblen House. The classes are donation-based, and all donations go to FOHW. 

VALUING, RESEARCHING, AND PRESERVING HERRONTOWN'S RICH CULTURAL HISTORY

Oswald Veblen's extraordinary career has been gaining increasing attention since FOHW president Steve Hiltner began researching and posting about the Veblens at VeblenHouse.org in 2010. On Sept. 4 this year, Steve teamed up with historian Cindy Srnka to present a talk at the Princeton Public Library entitled "How Oswald Veblen Quietly Created Einstein's Princeton." Drawing a standing room only crowd, the talk described how Veblen played an outsized role in creating the Princeton that Einstein ultimately chose to be his new home. 

Also in 2025, an online exhibit by the Institute for Advanced Study credited Oswald Veblen for his leading role in aiding displaced scholars in the 1930s and '40s. And Princeton University named the South Terrace at Prospect House in Veblen's honor.

THANK YOU TO THE FOHW BOARD, VOLUNTEERS, AND SUPPORTERS

So much goes into sustaining a nature preserve and the nonprofit that cares for it. As we bring our mix of tradition and innovation into 2026, I'm tremendously grateful to our board, volunteers, and supporters who contribute so much meaning, community, and all-round positive energy to this charmed place in Princeton. 

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. 

The Pleasure and Aesthetics of Native Seed Collection

One of the more pleasurable and aesthetic outdoor experiences in the fall is gathering seeds. I claim no expertise, but adhere to one simple rule: let the stem below the seeds turn brown before harvesting. And harvest when the seeds are dry. Also, be messy. Let some of the seeds fall where they would have fallen if you hadn't come along to take some. Alright, that's three rules. But that last rule is especially enjoyable. How many times in your life have you been told to be messy? 

There are more official rules out there for seed collection, particularly of uncommon species, but nearly all the seeds I collect now are either from my backyard or the Botanical Art Garden, both of which I planted. It's gratifying to see these new populations of local genotypes thriving, and to expand their local presence further. 

The plants I harvest from tend to be generous towards a human tendency to procrastinate. Many species hold on to their seeds for months in the fall and into the winter. But the prettiest time to be picking them is sooner rather than later, as they become increasingly weathered and threadbare as winter progresses.

Harvest of wild senna, seen in the first photo at a lovely stage when the leaves contrast with the dark seed pods, can be postponed considerably, as the pods hold onto the seeds for months.

The bright, fluffy clusters of ironweed seeds are easy to identify on stems that can reach 8 feet.

Rose mallow hibiscus (Hibiscus moscheutos) holds its seeds in convenient cups. Best not to wait too long, because there's a slow attrition to spillage and insects as winter sets in.

As with other sedges, the seed clusters of morning star sedge (Carex grayi) will break apart as fall progresses. Some other local sedges with easily collectible seeds are squarrose sedge and fringed sedge.

The seeds of bottlebrush grass, attractively arranged along the stem, were already starting to fall off when I collected them in late October. Just grab the dried stem between thumb and finger and pull upward to strip the seeds. This is an attractive understory grass. 

The seeds of turtlehead (lower left in the photo) are still ripening, having shown their own form of procrastination, waiting until early fall to bloom.  

Collecting seed has extra meaning and purpose this fall, because many of them will be planted along a wooded slope in Herrontown Woods where a large clone of wisteria had pulled down some of the trees, creating openings where sun can reach the ground. Years of effort, particularly with the consistent, transformative work over the past year or two by volunteer Bill Jemas, has largely snuffed out the daunting wisteria clone that had taken over an acre or two, choking other growth as it steadily expanded along this broad hillside. It even somehow traversed the creek and was headed towards the Botanical Art Garden, adding another layer of urgency to knocking it out. Into the void created by our wisteria removal has come garlic mustard and stiltgrass, but this year we pulled those before they went to seed. 

With much of the slope now bare (the photo shows wisteria to the right, cleared areas to the left), it's time to introduce native plants. We could toss the seeds hither and yon, but I like to give them a better chance by being more deliberate. Deer are an issue, of course, given their appetite for native plants, and my plan is to plant seeds in small circles here and there, creating loci a couple feet wide. I like to scrape a thin layer of dirt away, scatter some seeds, then sprinkle some dirt on top and tamp it down. Then I'll place a 3 foot high plant cage around each circle. Those that grow inside the cage should be protected enough to mature and produce seed that can then scatter beyond the cage on its own in subsequent years. 

It's actually a good way to find out which species the deer leave alone, and which they munch on. We are, in a way, creating "deer feeders" by protecting a few plants inside the cages--plants that each year spread beyond the cages, where the deer can eat them. This approach has been successful at the Barden. Thanks to the town's investment in annual deer culling, many of the plants that sprout beyond the cage survive. 

Of course, all of this thus far is talk. Procrastination is a particularly powerful factor when it comes to getting plants or seeds in the ground. There's so much other work to be done! What's real and lovely, and has actually happened, is the seed collecting. 

Last Chance to Pull Stiltgrass -- 2023

This week and maybe next are your last chance this year to pull stiltgrass (Microstegium vimineum). This mega-invasive is an annual, so the logic of countering its spread is to pull it before it can produce and drop seed. If the seeds haven't loosened yet at the end of the stalk, you can still pull it. Throw it in the trash, or if there's a lot, make a big pile of it so that any seeds that sprout the next year will all be in one place and easily covered or pulled. Definitely don't put it in your compost if its seeds are forming. If stiltgrass is just starting to invade your yard, pulling as completely as possible now will greatly limit its seedbank for next spring. Another strategy for large stands is to let the stiltgrass grow, then just as it begins to flower mow it short and hope its feeble roots don't have enough energy to grow another flowering stalk. 

For those fuzzy on identification, google lots of images, and look for the silver line running down the middle of the leaf. Stiltgrass can grow in the shade or sun, climb up to four feet, or thrive in a miniature state while ducking below your mower in the lawn. It's incredible survival skills include being incredibly inedible for wildlife. Stiltgrass gives nothing back to the habitats it increasingly dominates.

More on Stiltgrass, and a Success Story

Walking in the local woods, you've probably seen this kind of scene--what looks like a grassy meadow extending through the forest. In the filtered light of the understory, its simplicity and lushness may have some visual appeal. And yet, in some ways what you are looking at is the ecological equivalent of an urban food desert. 

Stiltgrass is an introduced plant that could be called a pervasive invasive, able to thrive most anywhere and dominate whole landscapes. Its success has come in part through being inedible. As wildlife selectively eat native vegetation, the stiltgrass expands, preventing the native plants from rebounding.

Unlike another nonnative annual weed that can look similar, crabgrass, stiltgrass becomes ubiquitous because it can thrive in sun or shade. That means the stiltgrass invading your lawn and flower beds can continue spreading ad nauseum into the nearby forest, or vice versa.

We used to call it bamboo grass--something in the shape of the leaves is reminiscent. The stiltgrass name refers to its angular growth, with each segment supporting the next as it climbs up and over fallen logs and other plants. Packing grass is another common name, referring to how it was once used to pack porcelain for shipment. That's probably how it first reached the U.S., in packing crates sent to Tennessee. 

When I first encountered it, growing on the bank of Ellerbe Creek in Durham, NC, I thought it graceful. Then came Hurricane Fran, bringing floods and fallen trees. In the aftermath of that massive disturbance, stiltgrass exploded in the landscape, expanding and ultimately choking forests with its vast, dense stands. New Jersey proved no different. 

Stiltgrass tends to establish itself along roadsides. Here it is growing in a green ribbon along Herrontown Road. Trails, too, provide an avenue for extending its reach, its tiny seeds carried on boots or the hooves of deer.

Though stiltgrass has covered large areas of woodland in the eastern U.S., we have found it worthwhile and even satisfying to counter its relentless incursions. Today in the Barden at Herrontown Woods, some volunteers pulled it out of a patch of native jewelweed along the edge of the parking lot. 

Nearby, on land where we have largely eliminated a massive clone of wisteria, stiltgrass was starting to move into the void. If nothing were done, this open woodland would have become a pasture of stiltgrass. But we have acted early enough to be able to remove all of this year's stiltgrass, dramatically reducing the seeds available for next year's crop. This photo shows the last patch before we pulled it. 

Interestingly, there are native grasses that look a little like stiltgrass, the main one being Virginia cutgrass (white grass), Leersia virginica. It has longer, narrower leaves that lack the silver stripe down the middle. As is a common ecological refrain, the native grasses "play well with others," not forming stiltgrass's massive, exclusionary stands. Some smartweeds like Lady's Thumb can also bear a resemblance.