Groundsel Tree and Catching Invasive Species Early

The problem with problems is, if they are solved early on, no one knows how big a problem they could have ultimately become.

-- Yurs Trulee 

Many of us are immigrants in our own country. If, for example, you moved to the east coast after growing up in the midwest, or vice versa, you're an immigrant of sorts, bringing experiences and sensibilities that may be new to others around you. My multiple immigrations in my home country have a botanical component. As I've moved from the midwest to the south, then to the east coast--tending to habitat wherever I live--I've brought with me experiences that less traveled land managers may not have had. And like an immigrant from another country, I don't lose a caring for my land of origin.

It's interesting to see how this plays out with invasive species. If I see a species like Chinese bushclover, which grows rampant in North Carolina, starting to pop up in fields in Princeton, I can warn others of the risks of not taking action. Similarly, when I spotted garlic mustard and lesser celandine growing in Durham, NC, I sounded the warning, having seen how the plant has behaved in northern states. And if I hear that the stiltgrass that chokes many woodlands here in the east is starting to spread to my home states of Wisconsin and Michigan, I can do my best to send warning back home to act early and often. Otherwise, each state has to learn lessons the hard way.

At the same time, one hesitates to raise alarm. Might a plant that's invasive in one state prove more docile in another, due to differences in soils and climate? This quandary played out recently while driving to a band rehearsal on Lawrence Station Road, down past Quaker Bridge Mall. Growing along the roadside amidst autumn's reds and yellows was a sudden burst of white. Having lived in the piedmont of Durham, NC, I could see both the beauty and the portent of this unusual presence in the local landscape.

Groundsel Tree is deceptive in many ways. It's called a tree, but grows more like a big multi-stemmed bush. The bright clouds of white produced in late fall look like flowers, but are actually thousands of fluffy seeds that fly far on the wind. 

Another deceptive trait is that groundsel tree (Baccharis halimifolia) is native to the New Jersey coast. Perhaps we should celebrate that this coastal species has moved inland bringing its fall nectar and showy seeds to the Princeton area. 

And yet, my years in Durham, NC showed me how aggressive this coastal native can become when it spreads along freeway corridors up into the inland piedmont. It can invade grasslands and create dense, exclusionary stands (see photo), reminiscent of the callery pear that lines many roadsides in New Jersey.

But is it behaving that way in NJ? I sent an inquiry to the Stewardship Roundtable listserve that many of us land managers participate in. Responses mixed praise for its positive qualities with some mild concerns. The specimen I encountered on Lawrence Station Road looked to have sprouted only two progeny since my first encounter with it, ten years ago.

One respondent, David Seiler, mentioned a big patch growing along 295 past 206. That sounded more like the behavior I had witness in NC. 

Thus began a journey. I checked iNaturalist to see where in Mercer County it had been documented. Just one spot in Princeton seemed legit--in Mountain Lakes preserve. 

I decided to check out the big patch along 295, now being a good time to spot it, while it is bright white with seed.

Hard to miss the long stretch of that bright white, mixed with the tassels of Phragmitis. But the backdrop of evergreen trees isn't natural to our area either, suggesting the groundsel trees were part of an ornamental planting installed between the freeway and a housing development. A well-intentioned planting could provide abundant seed for a new invasive in Mercer County.

Another data point on the iNaturalist map took me to a beautiful pond on the backside of the fabled Lawrenceville School that has a beautiful stand of bald cypress.

Where the groundsel tree is documented on iNaturalist, I found stumps. According to staff at the school, a landscape architect named Elaine Mills marked plants for removal along the pond this fall. If the stumps are former groundsel trees, were they removed for aesthetic reasons or over concerns of potential invasiveness? No answer yet. 

So, this is the quandary. As a land manager, do you sit back and let a newly arrived species like groundsel tree grow, appreciating its positive traits? Or does one heed warnings of its potential invasiveness in other states, and remove it while control is still possible? 

The problem with problems is, if they are solved early on, no one knows how big a problem they could have ultimately become.

Related posts:

The Mystery Tree Found in Autumn Hill Reservation

Speech at ECWA's 20th Year Celebration

New Invasive in Durham's Duke Forest Neighborhood

Fall Colors Walk and Other Weekend Events at Herrontown Woods

The Friends of Herrontown Woods is hosting various events this weekend. I'll be leading a Fall Colors walk Sunday, Nov. 1 at 11, but before that will be May's Cafe--coffee, tea, and baked treats served in the Barden, 9-11:30am--and before that will be the last session of Gratitude Yoga for the year on Saturday, October 31, at 11am, next to Veblen House. 

Don't forget to "fall back" timewise on Sunday.

The Sunday walk will focus on the woody plants that turn color this time of year, be they trees, shrubs or vines. Please register on the FOHW website. Though the walk is full, you can sign up for "overflow" and we'll figure out how to accommodate everyone.

We'll start at the Barden (600 Snowden Lane) and head up the boardwalk to Veblen House and beyond. 

One shrub people love to see is Hearts a' Bustin, the native Euonymus with ornamental seeds. We have a bunch of them in the Barden. Deer love them, too, to eat, so we protect them until the shrubs grow beyond the reach of the deer and can show off their wonderful qualities.

Another big surprise this time of year is the flowers of witch hazel--a Herrontown Woods native that blooms in November.

The most common native shrub is the blackhaw Viburnum, named for its berries, aka "haws," which turn black when ripe.

Along the walk I am hanging plant labels on many of the 70 species of trees, shrubs, and vines--an astonishing diversity for just one corner of the woods. This preserve is such a special gift the Veblens gave Princeton back in 1957. The habitat restoration our nonprofit has been doing over the past thirteen years has steadily revealed the depth and beauty of that gift. Important as well has been Princeton's management of the deer population, which set the foundation for our restorative work and helped the native flora to rebound and flourish. 

Below, a flowering dogwood that gets enough sun in the summer to put on a big show in the fall.

Native Landscaping at Princeton University--Taming the Tiger of Weeds

There's a quiet drama playing out on the grounds of Princeton University. In recent years, the University has been making a shift to landscaping with native plants. Homeowners, too, are being encouraged to go this route, so it can be instructive to take a look at how the University is doing. Despite all of its resources, the University struggles like the rest of us. Anyone can mow a lawn, but a complex native planting requires expertise to maintain. It takes skill, strategy and understanding to work with nature, rather than simply suppress it with a mower.

This post documents some ways the University is making native plantings easier to maintain, but points out the risks, past and present, of not investing adequately in maintenance. It also describes how early, strategic intervention can steadily reduce maintenance needs, and tame the tiger of weeds.

First, a review of the University's successes and failures over the years. 

One success thus far is the Betsy Stockton meadow, dedicated in 2018 atop the underground portion of the Firestone Library. A profile of the meadow that I wrote in 2024 mentions some weedy crown vetch beginning to spread through the beds, but it looks like the caretakers have since intervened.

Another native planting, around the neuroscience building, showed initial promise in 2014, but was mowed down two years later after becoming overwhelmed by weeds. Those grounds are now dominated by the nonnative super-invasive mugwort.

A native meadow planting at the Butler Tract in 2016 suffered a similar fate. 

In more recent plantings, the University has adopted a couple strategies to avoid losing out to weeds. One is to plant dense stands of natives. 

Here's partridge pea planted thickly. A nitrogen-fixing legume with graceful leaves and long-lasting blooms, partridge pea has a lot to like.

And here's river oats, another native effective at forming dense stands. Personally, I don't plant river oats because it seeds into areas where I don't want it, but it makes sense for a dense planting on a university grounds.

Switchgrass, a native tallgrass prairie species, grows thick near the soccer fields. Planting a solid stand of one species requires less knowledge to maintain, since the staff can be told to weed out any plant that looks different, like the nonnative giant foxtail in there that could cause problems over time. 

Here's a dense stand of white snakeroot ornamenting Whitman College in early October.

A more complex native planting with multiiple species near Myslic Stadium is doing well.

It's fun for a botanist to stroll up to a soccer game along a pathway bordered by side oats grama, a grass common in the Great Plains. 

Other newer plantings that looked great for a couple years are now struggling as weeds have moved in. This impressive stand of native cutleaf coneflowers along Fitzrandolph Road is besieged by foxtail, crabgrass, and other typical weeds. You can see where glyphosate was sprayed along the edge as a preliminary step, but the weeds were left to go to seed in late August.

By chance, one of my visits to the campus plantings coincided with a work crew immersed in weeding the beds across the street. The piles of weeds on the walkway attest to how much work needed to be done.

Before hauling away a bucket full of weeds, the supervisor told me a few things about maintaining the new native plantings. He was frank about the situation. The work in the heat of late summer is hard on his crews, and it seems they had to hire outside workers to augment staff. 

He said the weeds they remove are then composted and added to mulch that they then spread on the beds. If the composting process isn't hot enough to kill the weed seeds, they are then applying mulch that will sprout weeds. 

Here is a freshly weeded bed, demonstrating a second approach to sustaining native plantings. Rather than planting densely, space was left between desired plants so that any weeds growing inbetween could either be pulled or spot sprayed. 

I followed up with the grounds department, sending an email suggesting they use woodchip mulch that lacks weedseeds, perhaps getting some from the municipal composting site nearby. 

If there's one thing I've learned from all my years of gardening and land management, it's to stay ahead of the weed seeds. Garlic mustard, pilewort, stiltgrass, giant foxtail--we pull them all at Herrontown Woods before they can produce zillions of seeds that would otherwise create extra work for years to come. It goes against human nature, and it goes against bureaucratic logic, which wants to do things on its own schedule. No, one has to keep an eye on the weeds, react to their schedule, not one's own, and intervene before they form seed.

To take just one example, while checking out one of the newer University plantings, I found one plant of stiltgrass. Elsewhere in Princeton, you might find billions of stiltgrass plants smothering the landscape, but here on campus there was only one to be found in a large native planting. I pulled that one stiltgrass before it could produce seeds, thus liberating the whole planting from this one incredibly aggressive weed. Gardening is much easier if you know what to look for and catch it early.

The vast majority of the university grounds is free of stiltgrass, and could potentially be kept that way, but I did find this one patch, growing just north of the New South building. Since the seeds get carried downhill by runoff, I "followed the water" and found where it had spread to create another patch just down and across the road. 

I sent an email to the facilities staff in late August, before the stiltgrass began to go to seed, encouraging them to intervene. A followup visit in early October found they had at least mowed the first infestation.

The patch further down, though, near Baker Rink, was left to go to seed. This infestation, which ultimately threatens a broad swath of campus, is still at an early stage where it could easily be knocked out proactively--an hour devoted each year to spraying it with super-dilute, low toxicity herbicide before it goes to seed, until the soil's seedbank of this pernicious weed is exhausted.

There's a philosophy, a strategy for success, embedded in all of this observation and advocacy. Some forty years ago, I had a powerful dream in which I was riding in an open car down a street near my house. I saw a large tiger ahead, resting on the ground. As we approached, my worst fears were realized. The tiger rose and jumped up upon me. As I tumbled with it out of the car and onto the ground, the fierce tiger became a kitten, with me bent over it, tickling its belly. Caring for a native planting can feel like a very long, drawn out version of that dream. Pull the weeds before they go to seed, and over time the weeds grow few while intended plants grow dominant. Weeding becomes light work. Toil becomes ease and enjoyment. The intimidating tiger turns into a gentle kitten.

That is what I wish for Princeton University's grounds. Aim for a zero tolerance approach to weed seeds, moving each year closer to a weed-free campus, with each year of tending native plantings easier than the year before. Let the tigers roar in the stadiums, but tame them in the garden beds.

Related reading: 

A good article in the Princeton Alumni Weekly: Princeton Landscaping Goes Back to the Wild With Native Plants

Four Emerging Invasive Plant Species in Princeton, NJ

Some invasive species have been in Princeton for a century or more, while others are just now arriving. Kramer's 1960s ecological study of Herrontown Woods mentions only Japanese honeysuckle as being overly aggressive in the landscape. Since then, as deer numbers rose and the native flora became intensely browsed, many more nonnative plant species have spread into local preserves to fill the void. No ecological study of Princeton in the 21st century would be complete without mention of a multitude of additional invasive species that gradually, quietly became established and now present a tremendous challenge for any land manager or backyard gardener. Call them too much of a good thing, with some good features but rejected by native herbivores and overwhelming in their dominance. Privet, bush honeysuckle, winged euonymus, Photinia, multiflora rose, linden viburnum, porcelainberry--their deeply embedded presence represents a deferred maintenance of daunting proportions.

Though we often think of them as a generalized menace, each invasive species has its own story of where and how it was introduced to the continent, and the extent of its spread. Having lived in Michigan, North Carolina, and New Jersey, I've seen how an invasive plant deeply entrenched in one region has yet to spread to another. The stiltgrass and lesser celandine that smother large areas of Princeton are just now starting to show up in Michigan and Wisconsin. The garlic mustard long common in the northern U.S. is relatively new to North Carolina. Even within Princeton, invasions can be very localized, affecting one yard but not yet another.

Here, for instance, is one solitary invasive plant out standing in a field near Carnegie Lake. By its scraggly tilted shape, you can tell it is Chinese bushclover, Lespedeza cuneata, also called Sericea lespedeza. I first encountered it in North Carolina, where the DOT (Department of Transportation) planted it along new highways to hold the soil on steep slopes. While serving one environmental goal--reduced soil erosion--this non-native bushclover's tenacious grasp of the soil abetted its spread into nearby piedmont prairies. Promoters of the plant's use for erosion control claimed its seeds would feed wildlife, but the small seeds moved through the birds' guts undigested. I've seen how it can take over, displacing diverse native meadows to form monospecific stands. The tragedy of Chinese bushclover's spread now extends to what few original tallgrass prairies remain in the great plains.

For decades, Chinese bushclover has been spreading along the gas pipeline right of way in Princeton. It also began invading Princeton's Greenway Meadows preserve years ago, became entrenched before anyone took much interest, and now the municipality is having a very tough time combatting it. 

What a pleasure, then, to remove just one plant down near Carnegie Lake, and thereby protect a whole field in five minutes. That's the magic of "early detection, rapid response"--intervening before a new invasive species can become established. Many weed warriors savor a big battle, but for me, being able to declare victory after the tiniest of skirmishes brings the greatest reward.

By these whitish flowers you can see how many seeds that one Chinese bushclover could have produced.

There are native bushclovers. One with pink flowers is called slender lespedeza (L. virginica). Another is roundhead bushclover (L. capitata). Typical of native species, they "play well with others," integrating into a plant community rather than taking over. I fought to save a stand of these from encroachment and takeover by Chinese bushclover in a preserve I helped create in Durham, NC, but wasn't able to devote enough time to succeed. Thus the preference for catching invasions very early, before the work becomes overwhelming.

Another invasive species knocking ever more loudly at Princeton's door is a prickly vine that grows so quickly it's called Mile-a-Minute. This patch is growing on a bluff overlooking the canal, just off Alexander Road. Having seen how the vine can smother vegetation in rural areas outside Princeton, I've snuffed out small patches I have found growing in town along roadsides and field edges, lest the seed be eaten and spread by birds. Keep an eye out for its distinctive triangular leaf. It's a very prickly annual, so wear gloves and pull its vines out before their berries can ripen.

This past summer, you may have noticed some yellow in your lawn that wasn't dandelion. Chances are it was a legume called birdsfoot trefoil. Farmers often include it in the seedmix for pastures. The way it's spreading across lawns at the high school, and here along the gas pipeline right of way in Princeton Community Village, it could easily come to dominate untreated lawns in coming years. 

Some will be aghast at the thought of calling Queen Anne's lace an invasive species. The flower is one of the most beautiful creations, and it's the wild version of the carrots we eat, Daucus carota. Highly likeable! But see how it is beginning to take over the upper detention basin at Princeton High School. 

I'm not surprised by this behavior because years ago I saw how aggressive Queen Anne's lace could be in prairies and along roadsides in the midwest. Seeing it begin to spread in New Jersey, I had hoped that it would behave more tamely here. Apparently not.

As managers of the detention basin vegetation at Princeton High School, our Friends of Herrontown Woods crew let them bloom, then pulled every last one before the seeds could mature. Here is a pile of hundreds of plants. I estimated that just one robust plant could produce 5000 seeds. 

Wild carrot is a biennial, producing leaves the first year, flowers the next before dying. Though we removed hundreds of thousands of seeds, there are plenty of first year plants remaining that will produce flowers next year for people to admire and, in an act of romance without finance, maybe cut to share with a loved one. 

There are many other emerging invasive species in Princeton, such as Japanese angelica tree and black jetbead. Each year, the municipality hires the NJ Invasive Species Strike Team to make a first strike at some patches of these. With followup by local nonprofits, the goal is to avoid the mistakes of earlier decades, when invasive species were allowed to spread undeterred.

A Curious Paucity of Ticks--Pushing Back On a Scary NY Times Article

I'd like to push back on an Aug. 20 article in the NY Times magazine about a rising tide of ticks. The article surely scared the bejesus out of anyone who ventured into its hellscape of graphic descriptions and imagery. One quote in the article recommends "staying out of the woods" to reduce the risk of tick bites and the panoply of diseases they can carry, yet it warns that even urbanites can no longer be assured "that glass, steel and pavement are a moat against woodsy threats." While deer ticks wait passively for a warm-blooded meal to come along, lone star ticks "can sense a target up to 15 yards away and aggressively pursue their prey." I try to imagine the logistics of verifying that claim of "up to 15 yards." 

The article's title, "The Summer the Ticks Took Over," stirs visions of hapless humanity reduced to cowering in a corner of the living room, scanning the perimeter for incoming ticks while clutching a can of bug spray. 

My experience, living in Princeton and spending long hours in the woods, on the trail and off, tells a much different story. The idea that good bugs, in particular the pollinators, are in decline while pests are on the rise seems only half true. Pollinators are noticeably declining, but in my experience so are ticks, house ants and spotted lantern flies. I work in woodlands and fields without much precaution and without apparent consequence. Tick checks come up empty. Similarly, the odorous house ants stopped invading our house several years ago. Spotted lantern flies, the oft-mentioned invader of recent years, have grown scarce in my part of town. 

The curious paucity of ticks goes beyond one perambulating land manager's observations. Others who work at Herrontown Woods report few if any ticks this year. One day I met two women who had driven from Long Island to Princeton's Herrontown Woods to take a walk in the woods. Their reason? Fewer encounters with ticks, which are way too numerous on Long Island. 

Does this good fortune extend to Princeton generally? I reached out to Jeff Grosser of the Municipality of Princeton Health Department, who offered the following supportive evidence in an email:

"Here are 2025 and 2026 stats so far for confirmed cases of tick-borne disease in Princeton. No confirmed alpha-gal in Princeton last year. In general, numbers in Princeton and our region are lower this year than previous years. We are also working through a trend analysis year over year that we will certainly share once it is compiled."

2025	PRINCETON	BABESIOSIS	<5
2025	PRINCETON	BRUCELLOSIS	<5
2025	PRINCETON	LYME DISEASE	63

 

2026	PRINCETON	ALPHA-GAL SYNDROME	<5
2026	PRINCETON	BABESIOSIS	<5
2026	PRINCETON	LYME DISEASE	41

 

If ticks are in fact causing fewer cases of Lyme in Princeton, it likely arises out of factors both intended and serendipitous. Beginning in 2001, then Mayor Marchand and other courageous leaders instituted a combination of bow hunting and professional culling to significantly reduce the deer herd. The backlash from animal rights advocates made it into the NY Times, but failed to overcome broad community concern about the high incidence of collisions with deer on the roadways. After using emotion-laden words like "slaughter," "devastation," and "massacre" to describe the culling of deer, the Aug. 20 tick article quietly acknowledges that the venison goes to food pantries. Fewer deer also means more native plants surviving in the woods.

In addition, local predators have upped their game. Foxes are particularly adept at reducing the number of mice that serve as a reservoir for the Lyme disease microbe. 

The article on ticks focuses on the bad news, particularly about lone star ticks that can give some people alpha-gal syndrome--an allergy to red meat. Much of the good news in the article is hidden in parenthetical and prepositional phrases: "(It’s worth noting that an alpha-gal allergy can, in many cases, eventually fade, if a victim steers clear of meat for a while.)" and "while Lyme is “basically treatable” in 95 percent of cases..." More overt is a robust discussion of vaccines and other deterrents working their way through research labs and trials. 

The curious paucity of ticks prompted reflection on other scarcities and abundances in local nature. My experience in the field in recent years is stirring an ever more complex mixture of gratitude and grief. Below are a couple examples.

Butterflies were particularly scarce in early summer, making the sighting of 8 tiger swallowtails feasting together on the nectar of a buttonbush in front of Veblen House at Herrontown Woods a cause for at least a brief celebration. I've been seeing more monarch butterflies this summer, mostly solitary but two at the same time recently at a detention basin wet meadow we created in Smoyer Park. 

Also in that meadow, there's now a surprising abundance of a favorite native wildflower, partridge pea. Keep the invasive species at bay, and native abundance can happen. And I haven't noticed a single tick on me after periodic work sessions there to remove invasives.

While scary articles boldly grab our sleeves and demand to be read, the good news, resigned to its parenthetical status, approaches from behind and taps us softly on the shoulder. "By the way," it says, "did you notice?"

Note: Thanks to Jeffrey Grosser of the Municipality of Princeton Health Department for this additional info on vector borne diseases that may be of interest to readers.

"In terms of the larger, available data, please see below:

 

• This is a good map from the CDC that compiles several tickborne diseases on the county level (Rickettsiosis, ehrlichiosis, anaplasmosis, babesiosis, tularemia, Lyme): https://www.cdc.gov/ticks/data-research/facts-stats/geographic-distribution-of-tickborne-disease-cases.html

 

• NJSHAD has county-level Lyme data: https://www-doh.nj.gov/doh-shad/indicator/view/LymeDisease.County.html

 

• This is a vector borne disease data dashboard from NJDOH and includes a tab on tick activity: https://www.nj.gov/health/cd/topics/vector_borne_disease_data_dashboard.shtml

 

• If he wants to view vector-borne surveillance reports from NJDOH: https://www.nj.gov/health/cd/statistics/arboviral-stats/"

Looking for Hope With Stiltgrass

Often, we think of good as struggling against evil, but a lot of problems are caused by too much of a good thing. Too much carbon dioxide in the air is an obvious though invisible example--vital in small amounts, destabilizing if allowed to radically increase. Plastic sure is handy, but a problem as it builds up in the environment. Many species considered invasive or weedy would be welcomed in the garden, forest and field if they didn't have a proclivity for taking over. What to do, then, about Japanese stiltgrass, the uber-invasive that rises like a wave in late August, lifting itself up and over other plants, preparing to carpet the ground with a deluge of seeds that will surely expand its dominion the following year? If only animals ate it, to keep it in check, but the plant seems of value only to itself. Its one use to people--historically as "packing grass" to protect porcelain for shipment--was also its means of spreading across the planet. 

Keeping some areas stiltgrass-free involves a lot of effort in August--the month of opportunity before it goes to seed. If I were a biochemist, working in a lab rather than out in the field, I would dream of someday discovering a compound that would magically release the landscape from stiltgrass's smothering grasp.

The vexing irony of stiltgrass (Microstegium vimineum) is that it is both frail and indomitable. Weak roots make it easy to pull, yet the dense congregation of billions of plants will quickly overwhelm and exhaust the spirit. Nor have any herbivores found its wiry, flimsy frame worth eating.

One of stiltgrass's strengths is also one of its potential vulnerabilities The species uses something called C4 photosynthesis. There are two main biochemical pathways plants use to harvest energy from the sun, called C3 and C4. It has to do with how the process of photosynthesis is organized in the cells. The "C" stands for carbon, which is ever so conveniently supplied to the plants in the form of airborne carbon dioxide, so they can turn it into sugars and carbohydrates--the building blocks of growth. Plants using the C3 pathway tend to prosper in cooler months and languish in hot weather, while C4 plants grow more efficiently in the heat of the summer. (Note: Follow the link above to a short video that explains why.)

If you've ever wondered why crabgrass becomes a problem in yards in late summer, its because it is a "warm season" grass that uses C4 photosynthesis to outcompete the C3 "cool season" turfgrasses. Corn is another example of a warm season C4 plant that gets going later in the spring, then grows robustly through the hot summer months. What makes stiltgrass invasive in nature preserves, while crabgrass is not, is that stiltgrass is one of the few C4 plants that grows really well in the shade, allowing it to leapfrog over the C3 plants all around it during hot weather in late August. 

If someone could develop a compound that selectively kills C4 plants while not harming others, it would be really handy for spraying stiltgrass in the shady forest understory where it may be the only C4 species. So, every now and then I do an internet search, using a phrase like: herbicide specific to plants that use the c4 carbon pathway. AI actually comes up with some interesting results, which you can access by clicking on "see more" at the bottom of this post.

In the meantime, there's still reason to harbor a little bit of optimism about stiltgrass. I remember the first time I saw it, a graceful little plant growing on a streambank in Durham, NC. It seemed harmless until it later exploded across the landscape in the wake of Hurricane Fran's mass disturbance in 1996. A similar story can be told in New Jersey, but even now, thirty years later, it's hold on the landscape is hardly uniform, giving some reason for hope. In my August perambulations, I find it clogging floodplains and proliferating across moist slopes, but many other areas remain surprisingly stiltgrass-free. Your yard may be clogged with it, but many yards have yet to be invaded, or have only a few that can easily be pulled before it goes to seed. If you're one of the lucky ones, now is the time to inspect your yard and pull out every last one, even the annoyingly tiny ones.

Princeton University is a good example of a campus that has very little stiltgrass and could remain so with vigilance. I recently found a patch just up from their New South building. This could easily be sprayed using a highly targeted, minimalist approach.  Stiltgrass's weak roots mean the spray can be very dilute. Otherwise, seeds from this patch will spread downhill, with the problem growing year after year. I alerted the grounds staff at PU, and hope they are proactive.

Meanwhile, in the yard in this photo, the infestation was small enough that I was able to pull up every last stiltgrass before it could form seed, tossing them on the driveway to dry. Since they were already flowering, they needed to go in the trashcan, not the compost. Sometimes multiple followups several days apart are necessary, because one always misses a few. The payoff comes as the job gets easier each year. 

For an annual grass like stiltgrass, no seed means no future.

Related post: Stop Stiltgrass From Taking Over Your Yard

Black Bear Scat Spotted in Herrontown Woods?

Herrontown Woods neighbor Paul Schedl, a frequent hiker in the preserve, helps out by alerting me to any downed trees blocking the trails, but his email this week was about a sighting of a different sort. 

"Bear scat," he asked? I forwarded Paul's photos to Jim Ferry, Princeton's Animal Control Officer, who confirmed. "Very good chance yes! Sightings have come and gone this year but yes, we've had several sightings this summer. No issues, just sightings."

Typically, the occasional bear sightings in Princeton are of young males searching for new territory. Previous posts on this blog about black bears show them most commonly coming through in late spring or early summer, with mid-August being the latest documented here, until now. 

Since no aggressive bears have been reported in NJ, I'll continue walking in local preserves, but it's a good idea to review the info in the link below, and step a little more noisily while hiking, so the bear has plenty of time to scat, so to speak. Also, the sighting is an excuse to include below my comic instructions from 2012 on how a proper Princetonian should behave when encountering a black bear.

In a followup email, Jim Ferry added this:

"On a local level, we tell folks to be bear aware and bring in any possible food source. Also the NJ DEP website has good info. Hikers can carry bear spray if they want, but I have not heard of any aggressive bears in our part of the state. If there was, I'm sure it would make the news."

From a 2012 blogpost:

At the presentation last month on black bears, given by state officials in township hall, I was astonished to learn that, in the very rare case that a black bear attacks, the best tactic is to fight back. Princetonians have not been called upon to display such courage since 1777, when we all could conveniently claim we had yet to be born. 

To bridge this gap between experience and expectation, I herein provide a translation of the wildlife officials’ instructions, customized to fit the Princetonian lifestyle:

Black bears are near-sighted, so make noise to avoid surprising it. If the bear stands up on its hind legs, don’t worry. It’s just trying to see you better. Make sure the bear has an escape route. For instance, if it is following you out of the public library, hold the door open and give it plenty of room. If you encounter the bear in the woods, or on Nassau Street, you can back away slowly, but don't turn your back to the bear. In a calm, assertive voice, put the bear on notice that you are a Princetonian fully armed with opinions, and will not hesitate to express them. 

Avoid eye contact. If it doesn't run away right off, bang the pot you happen to be carrying with you, or download a "kitchenware noise" app on your cellphone. Bears hate to cook, which explains their interest in garbage. Otherwise, clap your hands, raise your arms over your head, wave a jacket, all of which should make you look large and impressive.

On rare occasions, the bear will do a bluff charge, at speeds up to 35 mph. If a cafe is close by, this is a good time to duck in for a double latte. If that option is not available, then you'll need to dig deep. Fleeing will only make you appear weak. Perhaps the stirring words of a high school football coach will come to mind. In any case, stand your ground, wave your arms and shout. Pretend you're in front of town council, venting your outrage over moving the Dinky. The bear should veer away from you at the last moment, providing a bigger thrill than any 3D movie at the mall. 

If the bear actually attacks, which is extremely rare, it's time to drop all remaining pretense of civility. Fight back. Don't worry about the bear's lack of access to dental care. Without asking permission, bop it on the nose. Bears' noses are 100 times more sensitive than ours. Use this sensitivity to your advantage, all the while reveling in what a great story this will make to tell the grandkids.

In case you surf the internet for more info, don't be confused by accounts of how to behave when encountering a grizzly bear out west, where the protocol is completely different and not nearly so gallant. - July, 2012

The municipal website mentions fruits and nuts in the bears' diet, and some of the seeds in the photo above look a lot like pawpaw seeds. The pawpaws are starting to drop to the ground in our two pawpaw patches near Veblen House. The dietary needs of bears were not on our minds when we planted them.

Planting Trees Strategically to Shade Playground Equipment

People talk about planting trees, but there are still a lot of parks in the world with play equipment that gets burning hot in the summer for lack of shade. Why, I often wondered as a parent of young kids, aren't shade trees planted strategically, where their shade will do the most good? It takes some imagination, to envision the full-sized tree a sapling will ultimately become, and some belief in the future, whether one's going to be around to see it or not.

In 2010, Rebecca Shell Kanarek, Princeton High School class of '99, contacted me with the desire to plant a tree in celebration of her and her husband's newborn son. Council woman Barbara Trelstad and I collaborated to choose a tree--an October Glory Red Maple--and arrange its planting. I suggested Potts Park, because it's playground equipment was roasting in the sun. My role was to decide where in the park to plant it. 

It can be surprisingly tricky to choose a good place to plant a tree. You have to imagine the sun's arc in summer and how the future tree will intercept it. At the same time, shade is not an unmitigated blessing. It's wanted some places and not others. In this case, I wanted to position the tree to ultimately shade both the climbing equipment and the swings, while keeping the tree's trunk out of the way of games and running kids. Planting it too close to other trees could slow its growth. And then there's the followup watering while it's getting established.

The spot chosen was a compromise, but sixteen years later, the tree is doing its job, cooling the play equipment in summer, then dropping its leaves to allow the sun to provide warmth in the winter. It's pretty straightforward. Trees grow, and the future comes.

And newborns grow up, too. 

(Thanks to Rebecca for the photo.)

Other posts about Potts Park and young trees

When an Entomologist Adopts a Meadow

When a native meadow is created in what used to be a sprawling expanse of grass in a city park, it's usually plant people--gardeners, botanists--who do the planting and the ongoing weeding.

But what happens when an entomologist comes along later on and adopts the meadow? This particular meadow, in Buhr Park in Ann Arbor, MI, exists and thrives in part because of a plant-loving neighbor, Jeannine Palms. Recently, though, I received an email from another friend in Ann Arbor, entomologist David Cappaert, who is spending his retirement documenting the mind-boggling diversity of insect life he finds near and far from home.

"Occasionally," he wrote, "I adopt an interesting local plant community, and spend serious time documenting the resident insects. In the last week or so, I’ve been looking at flowers and foliage in the Buhr Park meadows, by day and night."

The result is a gallery of photos of the many insects and spiders that visit the meadow or have taken up residence there. The photos with a white screen in the background were photographed at night when they were attracted to an illuminated white sheet stretched on a frame. 

Among his finds were a couple specialists. Most everyone knows that a monarch caterpillar feeds only on milkweed. But there are a lot of other specialist insects out there. 

David found a denticulate longhorned bee, which will look to the untrained eye like most any other bee, but whose larvae only eat the pollen of the boneset flower, 

and an ironweed plume moth, whose caterpillars only feed on ironweed--a very tall, reddish wildflower that blooms this time of year. 

Even if they lack the charisma of a monarch butterfly, knowing that there are insects that absolutely depend on this or that kind of plant brings new meaning to the work of planting and sustaining a meadow. Without boneset in the meadow, the denticulate longhorned bee would be out of luck.

Thanks to David for sharing his finds. Lucky is the meadow that gets adopted by an entomologist with a seasoned eye and the right kind of camera.

Note: For anyone in Princeton wanting to see a native meadow in full glory, I humbly nominate the detention basin at the bottom of the main parking lot at Smoyer Park, which is radiant now with the abundant yellows of goldenrods and partridge pea, the gold of Indian grass plumes, white clouds of late flowering thoroughwort, and reds of ironweed. Ripe for adoption by an entomologist.

Princeton Battlefield Landscape Returning to the 18th Century

For many years, I've been encouraging the Princeton Battlefield to extend its ethic of historical authenticity to its landscape. Not that my personal view held any sway, but with the arrival of the 250th, plans are now in place for that to happen.

For me, it began with a simple botanical observation. Why is the beautifully restored 18th century Clark House surrounded by a sprawling 20th century lawn and woodland edges choked by invasive Asian vines?

Annual volunteer days took on the bamboo and porcelainberry, but they tended to grow back. One small success was my skirmish with Mile-a-Minute vine, which was threatening to take hold along the borders.

Though a sprawling lawn worked great for flying kites, mowing such an expanse through many decades must have been quite a chore.

While George Washington's troops were victorious in 1777, the uber-invasive, nonnative porcelainberry mobbing the edges is clearly the current winner.

But change is now afoot. Centennials can stir people to action. For the Bicentennial in 1976, the Dogwood Garden Club planted dogwoods and daffodils, many of which ultimately were swallowed by the porcelainberry vines. 

The approach for the 250th is less ornamental, and geared instead towards giving visitors a real sense of the landscape as it existed during the battle. That means recreating 18th century roads and fencelines, removing some trees that block vistas, planting an orchard, and hopefully shifting towards a more authentic flora. I'm hoping they save the hican tree and the 15/16th American chestnut we planted, but at least their existence will live on in this blog. 

You can already see change in the reduced mowing.

Coming up in August will be a bioblitz, beginning 12-2 on Saturday, August 1, and continuing through the month. This means downloading the iNaturalist app to your phone, taking photos of plants you encounter at the Battlefield, and uploading them to iNaturalist. Then, over time, as 50 acres of mowed lawn will be reportedly restored to native meadow, we can track the botanical transformation. 

I feel good about having documented the Battlefield's botanical life up to now, and look forward to witnessing the exciting transformations ahead.