Saturday, May 04, 2024

Helping Herrontown's Beauty Express Itself

There's a lot of built-in beauty at Herrontown Woods. Rocks, wood, and water serve as the basic infrastructure upon which other beauties are overlaid. 

This time of year, it's the understory that gets to shine, just before the tree canopy envelopes the woods in shade. Much of the habitat restoration work we do at Herrontown Woods involves bringing back the beauty and functionality of the native flora. By removing nonnative invasive shrubs that clog the understory, we open up vistas and release the existing native flora from stifling competition. In a sense, we are filling in for the deer, which chow down on native shrubs while leaving the nonnative shrubs uneaten.

Walk up the new boardwalk from the main parking lot to witness a corridor brightened by flowering dogwoods, 
and hundreds of blackhaw Viburnum shrubs adding clusters of white flowers extending deep into the forest.
Redbuds can't survive in the deep shade of the forest, but they proliferate on the more open Veblen House grounds.

This year, we spotted two wild azaleas blooming along Herrontown Road. Fifty years ago, it would have sounded strange to be excited about a couple wild azaleas in the preserve. They were numerous back then, but have been literally laid low by increasing deer numbers and deepening shade. 

It's taken more than a decade of ramblings in the preserve to realize that some kinds of native shrubs we thought long gone in fact remain numerous on the forest floor in miniaturized form, browsed before they can grow sufficiently to bloom. The town's deer culling program has helped native shrubs like spicebush to rebound, but for some species, additional effort is needed.

Protected by cages and given some sun, pinxter azaleas, serviceberries, and hearts-a-bustin' are making a comeback in the Botanical Art Garden (Barden) next to the main parking lot. New plantings of native buttonbush, silky dogwood, pussy willow and elderberry are also being protected until they can grow and flower beyond the deer's reach.

In these ways, we help another layer of beauty in Herrontown Woods to express itself.

Tent Caterpillars and the History of Black Cherry Trees in Herrontown Woods

Black cherry trees draw attention in early spring because of the "tents" that tent caterpillars weave on them. I was surprised to find out that these tents are sometimes mistaken for gypsy moth infestations. There's also some disagreement as to how damaging tent caterpillars are to the trees they feast upon, so I decided to do some investigation. 

First, some distinctions between tent caterpillars and gypsy moths. Tent caterpillars are native, feed primarily on cherry trees, build conspicuous tents, and do their feeding on the fresh, tender leaves just beginning to emerge in April. Gypsy moths are a nonnative species imported from Europe, start feeding in May on a very wide spectrum of hardwoods and even some conifers, and do not build tents. 

Gypsy Moths
The story of gypsy moths in our area is most easily grasped by looking at how many articles about them have been archived in the Papers of Princeton through the decades. Outbreaks of gypsy moths remained minor in New Jersey until the 60s, then grew into massive defoliations of forests in the 1970s. By the early 1980s, gypsy moth populations were beginning to drop, thanks to a natural virus, introduced parasites, and aerial sprayings. A naturally occurring bacteria called Btk proved safe and effective when sprayed on trees where gypsy moths were feeding. There was a recurrence from 2007-8, but numbers have dropped off since then. Though the forests largely healed, the trauma of past gypsy moth infestations lives on in people's memories. 

Tent Caterpillars
What we have this spring, and springs extending back through millenia, are native tent caterpillars making their tents. 

Some sources on the web suggest that tent caterpillars, despite the powerful visual of the tents and defoliated branches, don't do enough damage to a tree to worry about. I'd really like to believe that, but this young black cherry tree, now bearing eleven tents from which the caterpillars make forays, is almost completely defoliated. 

They say a tree can survive one complete defoliation, but if defoliated several years in a row, it becomes increasingly susceptible to disease and insect attack.
Meanwhile, our very hungry tent caterpillars have even followed a branch over to a neighboring pin oak, which now, too, is getting chowed down upon.

We pause to note a couple recurring themes in nature. One is that the tent caterpillars will shift to a less desirable food source (a pin oak tree) if their favored cherry tree leaves run out. Deer, too, will begin eating less desirable foliage if they run out of their favorites. Thus, an overabundance of deer in the 1990s almost wiped out spicebush in our Princeton woodlands, despite it being low on the list of deer's preferred foods.

The other example of a recurring theme in nature is that the tent caterpillar eats only one crop of leaves, then is done for the year, allowing the tree to recover. The worst thing a predator could do is be so effective as to eliminate its prey. 

The introduction of a new insect, though, could throw off this balance of predator and prey. If another insect, say, a gypsy moth, came along and defoliated the same tree yet again in the same growing season, that tree would be in big trouble, having twice committed energy to manufacturing a whole crop of leaves, only to have them eaten. One question is whether the gypsy moth outbreaks in the '70s and '80s killed more of one tree species than another, causing changes in forest composition still noticeable today.

There's a lot of caterpillar behavior whose purpose is not immediately obvious. A week ago, caterpillars were crawling about on the outside of the tent, turning this way and that. My best guess was that they were expanding the tent by adding another layer of silk, but no strands could be seen coming from their bodies as they moved about. 

And why are these caterpillars clustered on the side of the tree, outside of their protective tents? Wouldn't they be easy picking for the birds that are said to consume them? 

As their spring residency has continued at the Barden in Herrontown Woods, the tent caterpillars have spun not only isolated tents but also enveloped the trunk and limbs in a silken web reminiscent of the webbing people drape on their shrubs for Halloween. A closer look reveals that the caterpillars have spun silken highways upon which they commute from tent to the "pasture" of the canopy. These highways are only one lane wide, requiring a caterpillar to temporarily step aside if it meets another coming the opposite direction. Some silken highways are suspended in air, like overpasses--a great way to smooth out the rough terrain of a black cherry tree's "black potato chip" bark. 

A tree colonized by tent caterpillars, then, has elements of occupancy, transport, and exploitation not unlike the human footprint on the land, with our homes, highways, and farm fields. A big difference being that the tent caterpillar's settlement is seasonal--more like the impact of nomadic tribes than our permanent villages--giving the tree a chance to recover.

Another big difference between tent caterpillars and other builders of shelters--bees, ants, birds, mice, people--is that the caterpillars don't seem to bring anything back to the shelter other than their bigger, well-fed selves. They aren't adults bringing food back to the young. The caterpillars, like super resourceful children, work collectively to raise themselves, then leave the tree on their own to pupate and turn into adult moths. 

A nice writeup about tent caterpillars (Malacosoma americanum) found at states that the broad side of the tents faces the sun, and that the caterpillars make three forays per day, returning to their tents inbetween. That will be something to check out next spring.

Surprisingly, the subject of wild cherry trees in what is now the Barden (formerly a pine plantation) came up more than 50 years ago, in Richard J. Kramer's book about Herrontown Woods
"Wild black cherry, which grows to magnificent size in the Allegheny Mountains, is a poorly formed tree in Herrontown Woods, occurring mostly in areas which were recently open fields. Its best growth has been in the pine plantation, where specimens are 30 to 40 feet tall and possibly may develop into good-sized trees. Apparently these black cherries were able to develop along with the young pines after these were planted in the open field. Although the birds do bring seeds of the cherry into the forest, the many seedlings and the few saplings that occur there grow poorly and remain shrub-like."
Gone now are most of the pine trees in the pine plantation, and those larger cherry trees are nowhere to be found. Our 12 little black cherry trees in the Barden, all saddled with tent caterpillars, must be the descendants of the larger cherry trees Kramer describes. Only one large black cherry tree is known to exist now in Herrontown Woods, almost completely free of tent caterpillars, growing next to Veblen House. Have tent caterpillars contributed to keeping the black cherry trees of Herrontown Woods from achieving full size, in the past as well as in the present?

If we wanted to relieve the cherry trees of the spring burden of hungry caterpillars, we could remove the tents and remember to crush the egg masses laid by adult moths on small branches in late summer, as suggested in this useful post about the insect. 

But as insect numbers continue to decline, the role of trees as food for native insects grows in importance. And if the cherry trees remain small, that will allow more sunlight to reach the many wildflowers growing in the Barden. Leaving the tent caterpillars to grow undisturbed can serve as an experiment, to see if they continue to flourish year after year, or if nature's array of predators, pathogens, and parasitoids finally up their game and reduce the burden these trees now bear.

Monday, April 29, 2024

Persistence Furthers With Garlic Mustard

Another weed that is risky to let get established in your yard is garlic mustard. The plant shoots up 1-3 feet high during its second year, and is easy to spot right now with its cluster of little white flowers.  The flowers look decent enough, but a laissez faire approach will lead to this weed taking over, altering soil chemistry and crowding out other flowers. The garlicky smelling leaves are edible, especially when young, but you'll never eat enough to control it. 

The strategy for combatting aggressive plants in the garden is different for each species. Garlic mustard is a biennial, meaning it gathers energy the first year, then blooms and dies the second year. If you leave it while it's flowering, chances are you'll forget to pull it later, after it has blended back into the green of the garden. By the time the plant dies and turns brown later in the summer, marring your garden with its skeletal remains, the seeds will have matured and dispersed, creating an even bigger problem next year. 

But foil its attempt to make and spread new seed, and the soil will eventually run out of seed to make new plants. Best to pull now, while in bloom, though it can be pulled any time before the seeds mature. "Grab low and pull slow" is a good motto for getting as much of the root as possible. Don't put the pulled plants in your compost pile. Even when pulled while young, there's still a chance that the flowers will mature into viable seed. 

To avoid having to stuff the pulled plants in trash bags to send to the landfill, what we've done at Herrontown Woods is pull every last one we can find, then pile them in an out of the way spot, so that any seeds that mature on the pulled plants and sprout the next year will be easy to find and pull. Pulling gets easier each year, until what once took hours now takes but a few minutes. 

All problems should yield so nicely to persistence. 

Related posts: 

Monday, April 22, 2024

Bringing the Garden Inside

This photo offers a great illustration of a time when it was common for homeowners to have an intimate knowledge and daily interactions with their yards. I grew up with such gardens just outside the door, but many kids grow up now with yards meant only to flatter the house, with sterile lawn, rounded shrubs, and tinted mulch--just one more stop for a landscape crew. Progress back in the 1950s and '60s promised more leisure, but instead, people are busier, and discouraged from gardening by predacious deer and fear of ticks. But I still encounter gardens that are clearly loved and cared for, and serve as expressions of the owner's personality in the choice of plants and the degree of order.

What didn't register for me until more recently is how much of a garden is meant to be brought indoors. Peonies, for instance, flop over so easily in a rain. This was puzzling to me, but makes much more sense when viewed primarily as fragrant flowers best adapted for a vase. A friend described to me how she grew up drinking tea made of sweet woodruff from the garden. It tasted best if harvested before it flowered, and so that distinctive flavor became bonded for her with early spring. 
The photo was one of those that makes the rounds on facebook, and included an attribution and appealing sentiment, below. One bond I feel with plants is that, no matter how old they get, they still produce new growth each year. They are then, the physical representation of our inner selves, which continue to grow after our physical dimensions have reached their limit. Like the gardener in the photo, we as humans have brought the plant world's eternal youth inside. 
"I asked an elderly woman once what it was like to be old and to know that the majority of her life was now behind her.

She told me that she has been the same age her entire life. She said the voice inside of her head had never aged. She has always just been the same girl. Her mother's daughter. She had always wondered when she would grow up and be an old woman.

She said she watched her body age and her faculties dull but the person she is inside never got tired. She never aged. She never changed.

Remember, our spirits are eternal. Our souls are forever. The next time you encounter an elderly person, look at them and know they are still a child, just as you are still a child and children will always need love, attention and purpose."

~ Author Unknown
illustration by Tasha Tudor

Thursday, April 18, 2024

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 later have pretty white flowers but spreads underground, popping 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. 

Lawn blotch has at least one positive, though. I've frequently seen the wild garlic being gratefully harvested by people of Asian heritage, to use in cooking like chives or onions. 

Lawn blotch as a phenomenon quickly passes, as the weather warms and the grass begins to grow, and lawn mowers once again impose a vertical conformity on the suburban landscape.

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 Masters 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.)"

Friday, April 05, 2024

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. 

Wednesday, March 06, 2024

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." 

Monday, March 04, 2024

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. 

Saturday, February 17, 2024

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.