Bamboo at Princeton Battlefield Gets its Summer Cut

This past Saturday, four of us gathered for a well-timed intervention at the Princeton Battlefield. The Friends of Princeton Battlefield had cut down a patch of bamboo in the spring, but the roots had quickly sent up a new crop of shoots--essentially foliar solar panels that would quickly begin resupplying the bamboo's powerful root system. By following up and cutting the new shoots, we deprived the roots of any return on their investment in new infrastructure. This is the third year we've done this, and each year the job gets easier. A massive stand of bamboo has been reduced to modest sprouts easily managed.

Thanks to volunteers Jill Warrington, Andrew Thornton, and the leader of the Friends of Princeton Battlefield, Kip Cherry. My participation was a bit of outreach from the Friends of Herrontown Woods, on the other side of town.

15 Flowering Dogwoods Rescued from Smothering Vines at Princeton Battlefield

Saving legacies is what Princeton Battlefield is all about, and one legacy we sought to save during a big workday organized by Kip Cherry were flowering dogwoods planted for the nation's bicentennial in 1976. I do most of my habitat restoration work at Herrontown Woods in eastern Princeton, but have been visiting Princeton Battlefield periodically to help tame bamboo monsters, care for native chestnuts and prevent vines from completely smothering the dogwoods. Having ten able and spirited volunteers at this year's Battlefield Society's Clean-up Day made real progress possible.

Kip Cherry (front left) began the afternoon with a moving description of the great battle that took place there in 1777.

Ten of us then headed across Mercer Street to liberate the flowering dogwood trees lining the edge of the field. The dogwood flower buds, poking through the drapery of vine growth, provided inspiration, with their promise of beauty in the spring, and nutritious berries for the birds in fall.

This was the curtain of vines we cleared away with loppers and pruning shears, while dodging poison ivy and the thorns of multiflora rose.

Here's a "before" shot, showing porcelainberry draped over three dogwood trees. (photo from last fall in a previous post)

And here's the "after" shot, taken from underneath the rescued dogwoods. We worked to create an open space between ground and lower limbs so the vines cannot easily climb back up.

Thanks to our brave and skillful crew, who came from near and far to liberate fifteen dogwoods over the course of three hours.

I liked this pose when the work was done. As always happens on workdays, there were good conversations to go along with the physical work. I gained some Veblen House-relevant information about Long Island and Connecticut, and heard some positive testimonials about electric cars like the Chevy Volt, which combines 60 mile battery range with a backup gas engine. One owner said she'd spent only $9 on gas since last summer, and hadn't noticed any rise in her electricity bill from charging up the car at home. While restoring some history, it was good to hear the future in the form of electric cars might be at hand as well. The same thinking goes into saving legacies, whether they be dogwood trees or the world's climate.

Senator Kip Bateman and Assemblyman Reed Gusciora dropped by to help out.

Here is Kip Cherry's summary of the day:

"Our Clean-up Day was a big success! The sun peaked out, and from all reports everyone had a great time, the Park looked a lot nicer when we were done, the CWT t-shirts were well received, and the Sierra Club came through. Senator Bateman and Assemblyman Gusciora both arrived and put their shoulders to the wheel. A large group of kindergartners picked up fallen sticks, while others removed invasive porcelainberry vines from dogwoods, cut down bamboo, and cleared encroachment along the pathway to the Quaker Meeting House. Special thanks to Kim Gallagher and Steve Hiltner for leading teams, and to Gary Nelson and Randy Riccardo for their hard work!"

Porcelainberry: the Vine that Ate Princeton

Here it's Friday of National Invasive Species Awareness Week, and nary a post about invasive species!

First, readers should be aware that there are contrarians out there, writing books, articles and opeds, trying to deny that invasive species are a big problem. It's fascinating to analyze their mental gymnastics and deceptions, which are similar to those used to deny the reality and danger of climate change. I've picked apart their faulty logic in posts that can be found at this link.

Now, on to our porcelainberry tour of Princeton. You won't find it in shady areas, where other invasives like stiltgrass, garlic mustard and winged euonymus thrive. Rather, porcelainberry threatens to smother all of those sunny openings and edges that shade-intolerant plants depend on for survival. Porcelainberry is related to our wild grape, but much more aggressive. Your first impression will be, "What lovely multicolored berries!"

Your second impression, as it climbs up the stems of your shrubs, like this elderberry, might be, "Oh, a little rambunctious, but those berries are so pretty!"

Your third impression, as it turns your yard or park into a monocultural topiary, will be more along the lines of, "OMG! HELP!" No, this is not kudzu growing along a freeway down south. This is porcelainberry winning a modern day Battle of Princeton, with stealth and persistence far beyond anything we distracted humans might muster.

This is what a nearby patch looks like in December, just down the road from the Princeton Battlefield, along Quaker Rd between Mercer and 206. Invasive vines and shrubs can seem less overwhelming in winter, which is actually a good time to remove them. In spring and summer, though, all that growth energy can be intimidating.

And this is what porcelainberry is doing to the sunnier portions of our lovely nature trail off the DR Canal Towpath near Harrison Street. The blackbirds may say hello to the berries, but it's bye bye to the diversity of native wildflowers underneath that foliar blanket.

Turns out porcelainberry's a soccer fan. Here it is in the cheap seats at Princeton University's Roberts Stadium, at one end of the field,

and at the other.

Here it is (light blue and pink berries) in that "second impression" stage, climbing over a honeysuckle shrub (red berries) at Quarry Park. Give it a few years and it may reach the "OMG" stage.

I haven't seen much of it in eastern Princeton yet, but we'd be smart to keep an eye out and remove it before the berries mature.

Otherwise, sunny edges everywhere will look like these hapless flowering dogwoods, planted at Princeton Battlefield in 1976 for the nation's bicentenial, and now struggling to survive beneath a spreading blanket of porcelainberry.

Note: You can help liberate the dogwoods from the porcelainberry and other vines on Saturday, April 1 at 1pm. I've been collaborating with the Princeton Battlefield Society on invasive species work for the past several years, and will be leading a group to preserve the dogwoods that line the field on the north side of Mercer Street.

Another group of volunteers will be continuing the multi-year effort to reduce the bamboo clones near the Clark House, which we're actually having considerable success without herbicide. 

For purposes of identification, here are a couple closeups of porcelainberry. The berries are distinctive, with different shades of blue, red and white.

The leaves are easily confused with wild grape. This photo shows how variable is the shape.

I hope everyone's having a happy National Invasive Species Awareness Week. We'll end with a short Q and A:

• Are all nonnative plants invasive? No. Nonnative refers to origin. Invasive refers to behavior.
• Why are invasive plants invasive? Oftentimes, it's because the native insects/deer, etc don't eat them, giving them a competitive advantage. To regain the balance we lost by introducing species that evolved elsewhere, people end up having to be the herbivores, wielding saws and loppers.
• One nice thing about invasives? They get us out in the woods for workdays. 

Starlings, Passenger Pigeons, and the Uneaten Acorns

Acorns, anyone? It's called "flooding the zone"--a technical term commonly used by botanists who grew up playing sports. Some people see it as a mess, and curse the trees. An alternative target for cursing, just to put it out there, would be the tree-phobic landscape of concrete and lawn that we impose beneath the trees. A forest floor is far more accommodating of arboreal excess. There, a tree can let it all hang out, let it all fall down--seeds of all sorts, leaves, branches--and the forest floor will shrug, take it all in, and turn it into wildflowers.

In town, the blanketing of acorns turns into a blanketing of oak seedlings, few if any of which have any prospects of reaching maturity. The seedlings seem to be saying, "Move me to an opening along the street where I could shade some asphalt", but it doesn't look like people are listening.

For some people, a love of trees is layered with deep resentment of this fecundity. For me, looking for logic in nature's ways, the question is not "What to do with it all?", but "What's missing?" Past posts about osage orange and honey locust ask the same question, and suggest a missing herbivore that would have consumed the abundance in the past. Botanical abundance has lost a once complementary zoological abundance.

A partial answer came this past Nov. 10, when masses of starlings swept through, congregating in the pin oaks behind our house. A closer look revealed they were gobbling down acorns. Minutes later, they were gone, having left our pin oaks a little lighter.

The starling is not native, though, so doesn't speak to what would have consumed the oaks' abundance historically. And starlings appear too small to deal with the larger acorns of other species such as red oak. Still, it's behavior suggests that the spectacular fecundity of oaks might once have fed a complementary fecundity in the avian world--some highly mobile species, large enough to deal with a broader range of acorn size, that could make quick wing across eastern North America, swooping in to feast and move on.

Enter Ectopistes migratorius, a.k.a. the passenger pigeon, a bird of spectacular mobility and historical numbers. The photos are from a wonderful NJ State Museum exhibit two years ago.

A fine writeup on the Smithsonian website says "the mainstays of the passenger pigeon's diet were beechnuts, acorns, chestnuts, seeds, and berries found in the forests." They may also have swept in to feast on the seeds of our native bamboo, Arundinaria, which at one time covered large areas in the southeast and, like other bamboos, typically bloomed only once every several decades.

It can be tempting to say that the starling is providing a service by partially filling the void left by the extinction of the passenger pigeon. A few books have come out in recent years that claim invasive species like starlings aren't a big problem after all. The books in turn embolden news editors to publish articles and opeds with a similarly seductive revisionism, showing the same willingness to cherry pick evidence and rush to conclusions. I've written detailed critiques of various of these, including one recent article that mentioned starlings.

It would be interesting to explore to what extent the massive numbers of starlings have filled the niche left empty by the extinction of the passenger pigeon. Though feeding habits may overlap somewhat, one big difference is likely to be nesting behavior. Starlings compete with native birds for nesting sites, while the passenger pigeons appear to have built nests on branches, where they would not have displaced birds seeking tree cavities.

What a Little Dew Can Do

Here's a bit of serendipity. Shadows play upon the grounds of Princeton Battlefield, charmed with dew on a Saturday morning.

Ever the resident tourist, a shadow selfie with Mercer Oak II. Had no luck getting the shadow to smile.

Sorry, but you can't look at any screen--TV or computer--without at least one obligatory car commercial popping up. The sound track runs something like, "If George Washington were alive today, ...", though he might eschew fossil fuel altogether and stick with a horse. Those founding fathers thought about long term consequence. What ever happened to that kind of thinking?

The original motivation for stopping during a drive by of the Battlefield was documentation, not aesthetics: to photograph the invasive porcelainberry overgrowing flowering dogwoods planted as part of the nation's bicentennial celebrations in 1976.

One of my recurrent cause celebres is to save the Dogwood Garden Club's dogwood legacy from the aggressive vine growth. From the green/yellow of the porcelainberry vines crawling over the red leaves of the dogwoods, you can see who won this year's skirmish. The Dogwood Garden Club doesn't know who I am, and for all I know they've forgotten that they ever planted these trees along the field's edge in the first place.

There was also an obligatory photo of the great disappearing bamboo patch. Two years ago, this was a thick clone of bamboo growing out over the path down to the Quaker Meeting House, but a series of well-timed cuttings with magic loppers over the past couple years have sapped vigor from the bamboo's giant root system. The decisive strategic intervention came this past June, when Kip Cherry and I cut down the regrowth from a cutting in the spring. It was some inconvenient toil, but deprived of any payback from that big investment in regrowth--two years in a row--the bamboo has nearly given up. A visit next spring should be light work, followed by a refreshing beverage on the Clark House porch.

Dew was also working some magic on the vista on Quaker Road near the towpath. Scattered pin oaks in a field of goldenrods.

Thanks goes to my daughter Anna for getting me out that way early on a Saturday, to drop her off for a busride to Philadelphia to do some canvassing. Otherwise, that encounter with morning dew would have never happened. Finally, a reason to be thankful for this election season.

To Save a Raingarden, Know Your Weeds

This is one of several posts intended to show how a knowledge of weeds can boost one's confidence as a gardener. The more confident gardeners we have in Princeton and elsewhere, the more gardens are likely to survive. Photos of some common weeds are below, but first, some background.

A number of local, designed native plantings have been mowed down in the past year or two. Examples include plantings at Princeton University, Harrison Street Park, and Westminster Choir College. The latter is featured in this post.

As with recycling programs, that mundane-sounding activity called maintenance determines success or failure. Without skilled, attentive management, all those lovely designs are just whistling in the wind. Though design and installation get all the respect and publicity, maintenance requires far more skill, because the gardener needs to know not only the intended native plants but also the dozens of weeds that will inevitably show up. Furthermore, each species must be recognized in all its different life stages.

How shall we define a weed? Since the intention of this raingarden is a mix of function (filter runoff from the pavement, provide some habitat) and ornament, a weed here is defined as a plant that lacks ornamental qualities and/or proves too aggressive. Even an intended plant can later be considered a weed if it becomes too aggressive in a particular situation.

If one stays on top of things, these plantings are relatively easy to maintain. But allow aggressive weeds like mugwort, bindweed, Canada thistle, or crown vetch to get established, and the owner will sooner or later decide it's all too much trouble, and mow it all down. Lawn is the ultimate control of a seemingly unruly nature.

This is what happened at Westminster Choir College's raingardens. Walking our dog, Leo, I watched over several years as the weeds moved in, competing with the intended wildflowers and switchgrass. Last year, the amaranth grew 7 feet tall. That must have done it, because this year, everything was mowed to the ground.

I had offered my services before, but this year I reached out to the sustainability director at Rider University, of which Westminster is a part, and offered to weed the raingardens and gradually shift them back to natives if they would commit to not mowing. She agreed, and the mowing stopped. Essentially, I had just acquired a new pet, a hybrid between tame and wild, requiring considerable human intervention at first, but less as time goes on if the "parenting" is good.

The resulting growth would be a bit intimidating for anyone who doesn't know plants. There's a sea of crabgrass, nutsedge has an ominous foothold, the amaranth is again showing vertical ambitions, but amidst all this are some promising signs. Blue vervain is making a comeback, attracting skipper butterflies,

and a robust ironweed is poised to flower in its new freedom from the lawn mower.

Below are some of the weeds to be contended with. Different strategies are required, depending on the species. A few weeds, like pilewort, three seeded mercury, and horseweed, are native, but most are introduced.

Crabgrass! Note the horizontal growth form and the finger-like seedheads. No attempt to control it, given it's vast numbers. It's an annual, so will die this fall and hopefully be less of an issue next spring as the intended plants begin shading it out.

Green amaranth overgrowing a blue vervain (yet to flower). It helps to note the smooth margins of the amaranth's leaves, contrasting with the toothed leaves of the vervain underneath it on the right. Also, a different shade of green.

All the amaranth came out, because it would be unsightly if allowed to grow tall, and thereby give Westminster an excuse to begin mowing again.

Fortunately, it had rained a couple days prior, the soil was sufficiently soft, and their taproots yielded to a slow, firm tug. Since weeding is so much easier after a rain, a flexible maintenance schedule can greatly reduce the work needed.

Pull with your arm, not with your back.

Horseweed has had a great year in farm fields and empty lots, and is vying for space here. Pull before it can set seed.

Nutsedge spreads underground, invading lawns and flower beds. Pulls easily, but likely will pop up again, a bit weaker each time. It's a bamboo situation in miniature, requiring that one steadily deprive the roots of energy from those solar panels called leaves.

One of my favorite edibles, lambs quarters. Either pull or leave a few to munch on. Can get way too tall, though.

Barnyard grass is not particularly aggressive, but is best pulled.

A species of smartweed. These Polygonums tend to be problematic, and sometimes very aggressive. Likely to get pulled.

There are different kinds of thistles. This is not the dreaded Canada thistle that invades with its underground rhizomes, but will likely come out if I remember to bring gloves or a shovel.

Three seeded mercury is a native annual with a weedy look to it.

Surely a mint, with the characteristic square stem, probably catnip, with the tiny flowers of horseweed in the background. Only one in the whole raingarden.

The weeding session took less than an hour, given the raingarden's soft soil. Maintaining a raingarden is 90% knowledge and strategy, 10% work. Know your weeds and their potential for being problematic, time the weeding for when the ground is soft and before the weeds spread or set seed, and pretty soon the raingarden will be giving a lot more than it takes. These are the principals that have worked in the past, and are now being tested at Westminster.