Lawn Blotch 2024

Maybe people have another name for it, but every April there is a condition of some lawns that catches the eye. I call it "lawn blotch," which develops early in spring when the grass has yet to grow but other plants have.

Those other plants that spring forth here and there in a lawn might be Star of Bethlehem, which will have pretty white flowers but spreads underground and pops up all over the place in your yard. 

Or they might be the pretty but terribly invasive lesser celandine,  which will become a nuisance for you, your neighbors, and your local nature preserve if you don't spray it or dig it up.

Or they could be a weedy allium that I call wild garlic. 

None of these plant species are native. Lesser celandine is poisonous. 

But I've frequently seen the wild garlic being gratefully harvested by people of Asian heritage, to use in cooking like chives or onions. 

As an adendum, below is a fun quote from a post I wrote about lawn blotch eleven years ago. Though the climate has been changing considerably, lawn blotch still coincides with the Master golf tournament: 

"As master golfers stride the perfectly groomed grounds of Augusta National this weekend, showing their mastery over a landscape that's kept in a perpetual state of arrested development, let us glance out the window for a moment at the less applauded realities of the suburban lawn. In the Masters tournament, only the hazards--the trees and shrubs--are allowed to reach maturity. For the golfer, any encounter with interesting plants is a sign of trouble. And in the yard, the main threat to calm conformity is the plant that seeks to lead a full life, by flowering and maturing its seed. (Full disclosure: I lettered in golf in high school, spent part of a summer mowing fairways, and probably developed a keen eye for plants while searching for lost balls in the nearby corn fields and the very rough rough of our neighborhood's rough-hewn golf course.)"

Lesser Celandine Spreading Into Local Parks

Poisonous to wildlife, crowding out other plants, be they native wildflowers or turfgrass, lesser celandine spreads across sunny lawns and shady forests alike, forming dense, exclusionary mats that can extend far into the distance. 

I've written many posts about this highly invasive plant, and how it can be controlled with targeted, minimalist use of herbicide if one catches it early in one's yard or in a local park or preserve. Invasions start with one isolated plant like this, which can be easily sprayed with systemic herbicide without damaging nearby vegetation. (Or dug up and thrown in the trash, not the compost.) Of course, one plant looks harmless enough, but its rapid spread will change your view from "Gee, that's pretty" to "Help!!"

Incredibly, this spring I happened upon a homeowner in our neighborhood who actively sells lesser celandine and other plants she digs from her garden, apparently via facebook marketplace. Her garden is infested with the plant, and so this noxious weed will hitchhike in the soil of any garden flower she sells. Though it has a pretty flower, it's rapid spread will cause gardeners to lose control of their gardens, and to then serve as vectors for the plant's additional spread to neighboring lands. I asked the woman about the ethics of selling and intentionally spreading such an invasive species, and she refused to even discuss it. She blamed her unreceptivity on someone who had confronted her about it in an unfriendly manner. I asked "What if a nice person were to raise the issue with you?" But she still refused any discussion.

I may be having more success with Princeton parks. This spring, a friend, Mimi, was concerned about the status of the London plane trees along the Scott and Hella McVay Poetry Trail in Greenway Meadows, and asked me to take a look. The trees definitely need some attention, given all the invasive shrubs growing beneath them, but I also noticed that lesser celandine is beginning to spread through the park's meadow and lawn. 

Here's that classic "first plant" which would ultimately carpet the whole meadow with its poisonous foliage if not treated. 

And here's an early infestation in the lawn that extends down to the ballfields and into the land surrounding the DR Greenway Johnson Center.

I urged the town to take action, and it appears they will. 

This spring has not been ideal for spraying lesser celandine. Days have remained cool, which I personally like, but it's best for the temperature to reach 50 degrees for effective treatment. Of course, having just written that, I come upon a source that says at least 40 degrees. 

Glyphosate--much vilified for its overuse in agriculture--is still the most dependable systemic herbicide to use. If close to wetlands, a wetland-safe formulation (not Roundup) can be used, though it takes some sleuthing on the internet to find it. For foliage, a 2% solution is good, but some use 4%. 

I've heard that some land managers use an herbicide called Milestone, which may be a useful alternative, particularly because it doesn't harm surrounding grasses. 

If you read online about lesser celandine, you'll sometimes see claims that it must be sprayed very early in spring, before it flowers. Early spraying in helpful, but people should not be deterred from spraying later in spring as well. You'll also see claims that lesser celandine might be mistaken for the native marsh marigold. But marsh marigold is extremely rare. In all my explorations of Princeton's open space, the only marsh marigolds I've seen are the few that I have planted. 

Lesser celandine reminds us that we are all connected. What one person allows to grow in the yard can impact neighbors and nearby natural areas. The more a neighborhood becomes infested, the more likely it will spread to your own yard, through landscapers' mowers or on the hooves of deer. Thus, one person's problem quickly becomes other people's problem. It's important to be vigilant. 

Princeton Salamander Crossing Brigade

Meet the Princeton Salamander Crossing Brigade. They joined together one warm, rainy night last week with a shared mission to help the local amphibians safely reach their breeding grounds up along the Princeton ridge.

Their objects of affection and devotion are frogs like this one, 

and salamanders like this. Due to land preservation efforts that began with the donation of Herrontown Woods nearly 70 years ago and continue to this day with a critical initiative to save the 90 acre Lanwin tract, there is still enough forest and clean water along the ridge to sustain these charismatic and ecologically important creatures. After long winter dormancy, it's these first warm, rainy nights that stir wood frogs, spring peepers, and spotted salamanders to action. 

Their goal is to reach the vernal pools that dot the woodlands of the ridge, where they will gather to mate and lay clusters of eggs before withdrawing back into the forest. Only one thing stands in their way. 

 

Herrontown Road dates back to the early days of Princeton. It rides the top of the ridge, winding around the back side of Herrontown Woods. Hundreds, perhaps thousands of amphibians, seeking the vernal pools in which they were born, unknowingly risk being crushed when they cross this strip of pavement. A spotted salamander can live more than 20 years, so that each loss has consequences for decades to come.

Interest in taking action to help the amphibians, many of which are females carrying eggs, has been growing. This is our first year placing signs along the road, in an appeal to drivers to slow down and keep an eye out for the little creatures. Trish Shanley of the Ridgeview Conservancy introduced us to Charlotte Michaluk and her sister Sonja, who have been studying amphibians and received grant funding to make these signs.

We also had some signs hand-painted by Boy Scout Troop 43.

Inge Regan of the Friends of Herrontown Woods created a series of signs that add up to a message, inspired by the Burma Shave signage that once dotted American roadsides. 

We can hope drivers will respond to signage, 

but all too frequently, the result is this, 

 

and this. 

Even the most careful driver is unlikely to see this little frog, a spring peeper. Much of the damage done to nature by human activity is unintentional. Good will and good intentions are not enough.

In some places in the state, roads are closed on these first warm, wet nights so that amphibians can cross safely. It's also possible to build tunnels under the roads. But none of this is as yet possible for Herrontown Road.

Thus, it was time to don reflective vests, acquire strong headlamps and good raincoats, and gather at dusk to help the amphibians survive their road crossings. 

We first received training at a workshop led by staff of the Sourland Conservancy, ConserveWildlifeNJ, and Somerset County Parks Commission, who taught us basic safety protocols and how to pick up the amphibians. First and foremost, get off the road when a car is approaching, and it's important not to have any hand lotion that could harm the amphibians' sensitive skin.

Over time, FOHW board member Inge Regan has brought together a passionate group of experts and novices, students and teachers, neighbors and FOHW members, all of whom communicate by text via a whatsapp group, sharing knowledge and photos, planning action, and generally cheering each other on. Hopewell teacher Mark Manning and Princeton native Fairfax Hutter have been lending their expertise, along with Lisa Boulanger, a neighbor who has essentially adopted Herrontown Road, regularly picking up litter and protecting the wildlife. Also a font of knowledge is Princeton High School teacher Mark Eastburn, who along with his students has gotten involved. 

One PHS student, Bhavya Yaddanapudi, is conducting research on vernal pools in Herrontown Woods. 

Helping with the crossing, as Daniela Gonzalez of PHS discovered, offers a chance to get up close to animals that are otherwise elusive, spending most of their lives hidden under leaves and logs in the forest.

Inge Regan's son Dylan also lent a hand, highlighting the multi-generational nature of the enterprise. As Inge reported in an email: "On our biggest night, 2/28/24, we had 15 volunteers out. We had over 121 passing cars, and we were able to save 40 amphibians. There were 49 DORs."

DOR stands for "dead on the road" -- amphibians run over by vehicles.  

The following day, Bhavya's father, writing on the WhatsApp group, captured the sentiments of everyone involved:

"Was great to see so many come together last night. The DOR stats are startling to say the least, witnessing was even more painful. Pls count me in for any efforts to bring change to our town policies that can minimize this carnage. Thanks again for including us." 

Are Bubbles Trouble for a Tree?

One of the students in a class I was teaching about rocks at Herrontown Woods noticed something decidedly un-rocklike on a black oak we were passing by.

Foam was collecting at the base of the tree. Might it indicate some malady like decay or disease?

The bubbles, clustering like the frog eggs now being laid in nearby vernal pools, reached at least ten feet up the trunk. There was, however, no obvious wound in the bark that would suggest sap was emerging and interacting with the water flowing down the trunk from the slow morning rain. 

Not surprisingly, what seems like a very curious and rare phenomenon turns out to have been written about many times over on the web. Soap is made of salts and acids, and in this case the salts in dust, accumulating on the bark during a dry spell, combine with the acidic sheddings of the tree itself. Rain generates "stemflow" on the trunk, and as the water drips down over rough bark, absorbing these salts and acids, bubbles are formed. The tree is perfectly fine.

If we had had time, we could have examined other trees to see which ones and which kinds were collecting foam at the base. Smooth-barked trees like beeches likely would not generate sufficiently turbulent stemflow to create bubbles. Perhaps tilted trees, on which the stemflow concentrates on the lower side as it flows downward, would have more bubbles. The pace of rain may also be a factor. That day, the rain was steady but gentle. 

One reason this bubbling seems so rare is that we don't usually pick rainy days to walk in the woods. It's our presence, not the bubbles, that are rare.

While the bubbles were heading down the tree, a couple earthworms were heading up, apparently to escape the too soggy soil.

Speaking of bubbles, here is a post with photos of bubble patterns in the ice of Lake Carnegie during the winter of 2015, back before our winters turned liquid. 

Coming in March: Three Princeton Adult School Classes at Herrontown Woods

Through the Princeton Adult School, I will be leading or co-leading three classes at Herrontown Woods this March. Classes meet on Saturdays, 10-12. 

To sign up, scroll down through the list of Tours and Nature Walks being offered this spring by the Princeton Adult School. Discount available if you sign up for all three.

Class Descriptions

March 2: The Herrontown Woods Experience: Hiking and Exploration (Princeton Ridge Geology and Magnetic Rocks) - Why do magnets stick to some of the rocks in Herrontown Woods?Hydrogeologist Jon Johnson discovered magnetic rocks in Herrontown Woods and tracked them back to the mother lode. We will retrace his journey, learning about the Princeton ridge's surprising geology and ecology along the way.

March 9: The Herrontown Woods Experience: Hiking and Exploration (Signs of Early Princeton Along the Ridge: Quarries, Smallholder Farms, Timber Harvest) - The mix of nature and culture at Herrontown Woods provides a window into the past. Hidden in what today is a forest are clues to a time, a century ago, when Princeton's ridge was a patchwork of small farms, woodlots and quarries. Participants will learn to recognize these clues, and the history behind them.

March 16: The Herrontown Woods Experience: Hiking and Exploration (Salamanders and Frogs in Herrontown) - Herrontown Woods is a center of amphibian life along the Princeton ridge. We'll visit some of the vernal pools where frogs and salamanders gather in the spring to lay their eggs, and learn about their varied life cycles, as well as efforts to help them survive road crossings during spring migration.

Encountering Old (Plant) Friends at Fairchild Tropical Botanical Garden

Among the many surprising encounters we had during a visit to the Fairchild Tropical Botanical Garden--during a holiday spent in Coconut Grove, more than a year ago now--was the opportunity to sit down and have a chat with the celebrated writer and conservationist Marjory Stoneman Douglas. She's aging well. After a brief bout with death in 1998, by which time she had reached the age of 108, she still looks to be going strong 25 years later. Sitting alone on a bench, she looked like she wanted company, perhaps to tell me about her seminal book, The Everglades: River of Grass, and how she helped found the Fairchild Gardens.

Walking the paved trails that wind through 83 acres, I felt suffused with a bloom of happiness. Maybe I was empathizing with all the happy plants. In Princeton, things can be bleak in winter, but even in summer there is evidence everywhere of trees dying back due to introduced insects and diseases. This patch of Florida is by comparison exuberantly florid. 

Or maybe it was the endearing mix of impeccable and casual, which perhaps reflects the Garden's varied founders, who range from an accountant/businessman to a worldwide explorer to environmental advocates like Douglas. The grounds are at once formal and informal. Paved trails have imprints of leaves and fruits. Encountering no clear route from the parking lot to the visitors' center, we ducked through a shrub border. The lawns are manicured, and yet the plant labels are low-key, well-aged and aging well. 

Structures range from  a sophisticated greenhouse hosting tropical plants and myriad butterflies to this authentic-looking thatched roof pavilion. 

Along the winding paths, there were old friends, like this thriving ombu. Lacking true wood, it is really an overgrown forb masquerading as a tree. I first encountered it in Argentina, where stories tell of it giving shelter to gauchos out on the pampas. Its latin name, Phytolacca dioica, shows it to be in the same genus as our pokeweed. If you saw it blooming, as I did once in a park in the Recoleta neighborhood of Buenos Aires, you might think you're looking at a pokeweed 50 feet high.

How often do we get to see a baobab tree, and a massive one at that? 

Witnessing this assemblage of plants from around the world stirred all sorts of memories of past travels. This tree reminded me of a hike up into the hills outside Medellin, Columbia, in 1974, where a patchwork of hand-cultivated onion fields gave way to small hilltop forests of tree ferns and hummingbirds. 

Petrified wood triggered memories of visiting a petrified forest during a long drive through Argentine Patagonia.

And this swollen trunk brought the name "palo borracho" to mind, a name that translates to "drunken stick", in reference to the bottle-shape of the trunk. They are common along the streets of Buenos Aires. I think this one is Ceibe speciosa, the silk floss tree, closely related to the kapok tree.

The Garden's 83 acres were donated by an accountant and businessman named Robert Montgomery, who counted among his friends the globetrotting plant collector David Fairchild, who lived next door and supplied many of the plants. The garden's website describes how Fairchild "visited every continent in the world (except Antarctica) and brought back hundreds of important plants, including mangos, alfalfa, nectarines, dates, cotton, soybeans, bamboos and the flowering cherry trees that grace Washington D.C." 

The National Tropical Botanical Garden goes even farther in describing Fairchild's legacy: 

"Avocado, mango, kale, quinoa, dates, hops, pistachios, nectarines, pomegranates, myriad citrus, Egyptian cotton, soybeans, and bamboo are just a few of the thousands, if not hundreds of thousands of plants Fairchild introduced to the United States."

The desire to import plants that could prove useful for food, fiber, and other uses dates at least back to George Washington and Thomas Jefferson, but gained intensity during the golden age of travel--the late 19th century when Fairchild began his career. Plants were considered so important to the economy and security of the nation that the U.S. Botanic Garden--a particular passion of George Washington's--was placed next door to the Capitol building. That's it down in the lower left of this map. 

To 21st or even 20th century eyes, the proximity of a botanical garden to the nation's center of legislative power feels odd in the extreme. Plants are more likely now to be viewed as quaint decoration to soften the edges of our hardened world. When I visited the U.S. Botanic Garden, probably in the 1990s, the conservatory looked a bit down in the mouth, largely serving as a refuge for the homeless. More respect for George Washington's dream has been shown since then. 

Those must have been heady times, early in the 20th century, when Fairchild oversaw the import of more than 100,000 species of plants from around the world. Their utility and beauty promised to enrich our country by diversifying our farms, gardens and kitchens. Few, including Fairchild, wanted to think about the downside, as some of these imports escaped gardens and ran wild over the landscape, displacing native species. A botanical enrichment has contributed over time to an ecological degradation. 

I looked into whether David Fairchild ever came to terms with the potential for introduced species to run amok, and plan to write about it in a separate post. He was aware that some nonnatives like kudzu and lebbek were spreading aggressively, but there is no verifiable evidence as yet that he sounded a warning. 

It's heartening to see that the Fairchild Tropical Botanical Garden itself has evolved to take the threat of invasive species very seriously. According to multiple sources, it monitors closely its collection of exotic plants and takes action to prevent spread beyond the Garden's borders. I want very much to believe all this is true and will continue to be true, the better to enjoy the memory of my visit there, encountering so many old (plant) friends from my earlier travels around the world. 

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.