Mile-a-Minute Found at Princeton Battlefield

As if the massive invasion of porcelainberry, the "Kudzu of the North", at the Princeton Battlefield were not enough, I just discovered a patch of Mile-a-Minute there. This is, fortunately, only my second sighting of the prickly, fast-growing invasive in Princeton. The first sighting was in August of 2007, when I spotted it in a flower bed across Harrison Street from the Princeton Shopping Center.

For that first patch, it was relatively easy to contact the owner and convince her that it needed to be removed. The patch at the Battlefield is somewhat larger, about ten feet square, and has already produced berries that could be transported by birds to other locations. The next step is to go back with a sturdy pair of leather gloves and trash bags, and remove every last bit.

That Mile-a-Minute has a small foothold at the Battlefield suggests that it could have popped up most anywhere else in Princeton, so keep an eye out. The plant is an annual with distinct triangular leaves and a prickly stem reminiscent of our native tear-thumb. It should be pulled out and, if it has berries, placed in a garbage bag and put out for the trash. DO NOT put it in the compost, because the berries could then be spread.

It should be noted just how vulnerable we are to invasions of this sort. The Emerald Ash Borer's arrival in Princeton is a prime example. Accidentally imported to southeastern Michigan twenty years ago, it became established and therefore impossible to eradicate, because there was no "early detection, rapid response". Maintenance of the Battlefield grounds consists of mowing. Anything in the plant world beyond lawn requiring intervention is thus left to the chance interest and commitment of volunteers without a budget.

I happened to notice the Mile-a-Minute vine while checking the status of the ornamental flowering dogwoods planted long ago along the edges of the northern field at the Battlefield. I've been cutting the vines off, most years, but the porcelainberry is becoming increasingly dominant, smothering many of the dogwoods and other trees along the field's edge.

Here's a dramatic example, a dogwood barely visible beneath an oppressive cloak of porcelainberry.

On a planetary level, climate change was detected, but many with power to act have lacked a basic understanding of the consequences of delay. Here's where a naturalist's experience with invasives, or even a backyard gardener's experience with weeds like stiltgrass, mock strawberry, or ground ivy, can give insight into the importance of quick response. A ten foot patch of Mile-a-Minute seems minor, but without action, its berries will spread and the problem will quickly become too intimidating to dare act against. Bureaucracies do this all the time, as with Burmese pythons in the Everglades. Early warnings are ignored, and the problem doesn't become officially recognized as a problem until it's too big to solve.

Meanwhile, the vast lawn continues to be mowed, offering a superficial reassurance to passersby that the landscape is under control.

Italian Heritage of Summer Bounty

This has been a stay-at-home summer, except for a few train rides into NY, but there was one walk around the block with our dog that left me feeling like I'd just been to Italy. A diminutive, elderly woman with a strong Italian accent was picking peaches from a tree that grows near the street. I commented on the bumper crop, and she gave me a few to take home. Her husband had died a few years earlier, but her son cares for that enduring legacy of food-bearing trees left behind.

The yard is essentially an orchard, reminiscent of backyards I saw years ago from the Dinky-like Circumvesuviana train in Italy, packed with fruit trees and vegetable gardens. In Princeton, such a yard will be ringed by a strip of lawn, in a gesture of conformity to America's curious lawn fetish.

If I were to imagine an ideal yard, it would be filled with gardens and fruit trees, with solar panels (they're free now!) on the roof. Shade trees along street's edge would keep the asphalt cool while somehow not shading the food-bearing plants too much (we're talking ideals here). The Italian tradition, exemplified by a number of yards around town, at least show how the food portion of that ideal can be realized.

It looks to have been a great year for growing apples.

And this yard includes persimmons (not the native species),

and even chestnuts.

Just down the street, a young couple has planted fruit trees in their yard and solar panels on their roof. I hope the wisdom behind all this horticultural success is being documented and passed along. It would be heartening, and fortifying, to see this remarkable tradition in Princeton continue and expand, and see Italy's impact on Princeton's backyards equal the architectural legacy immigrant Italian stonemasons left behind.

Some links about Princeton's Italian heritage:
http://www.ppscf.org/index.html
http://dorotheashouse.org/history.html

Emerald Ash Borer in Princeton

Here's a stock photo of the recently arrived insect that will kill (there must be a better word) Princeton's most numerous tree species over the next decade. White ash, green ash, and the much less common black ash--all are vulnerable. The photo shows an ash tree with characteristic "D"-shaped exit holes. It will take a lot more than a penny to deal with the consequences of this diminutive beetle's appetite. I'll expand below, but I sent the quick read version out in a mass email that was then quoted in an informative article in the Town Topics:

"Emerald Ash Borer (EAB) was found in a trap set by the town arborist out along River Road. This small green insect, accidentally introduced to our continent from Asia, probably in wooden packing crates, has been spreading outward from its original introduction in the Detroit area, killing 100s of millions of ash trees. The insect will spread across Princeton over the next few years, eventually affecting all ash trees that haven't been treated. Highly valued ashes can be injected in springtime with an insecticide. The treatment can provide protection for several years. Of the various chemicals available, I've heard the most praise go to Arbor Mectin. Tree-Age has a similar formulation."

The Next Fifteen Years

So, what happens now, and what can we do about it? Princeton's arborist, Lorraine Konopka, sees this slowly evolving catastrophe following a fifteen year arc. In the first five years, EAB will spread around town, building up its numbers with each new generation. Symptoms are slow to manifest, but in various ash trees we'll start seeing dieback starting at the top of the crown and working its way down. Many ash trees are already suffering from ash decline, notably a disease called ash yellows, making it even harder to know for certain when EAB has invaded a particular tree. Homeowners will be forced to choose between spending hundreds of dollars every few years to treat favorite ash trees with systemic insecticide, or spending thousands of dollars later on to remove their dying ash trees before they become brittle and dangerous. The five years that follow will be marked by radical dieoff, both in town and in our nature preserves. Some woodlands where ash trees dominate will be decimated. We'll see otherwise green hillsides dotted with skeletonized remains of ashes. The five years after that, more or less, will see the last untreated ash trees succumb. The population of EAB will drop dramatically, but protected trees will continue needing new injections of insecticide, though potentially less frequently. Ash trees will still be found in nature preserves, but likely get attacked as they grow towards maturity. More on the aftermath at this post, written after a visit to Ann Arbor, MI.

Life Cycle

According to an EmeraldAshBorer.info webpage, the Emerald Ash Borer hatches into an adult in May and June (coincidentally, emergence is said to begin around the time that black locusts bloom), flies to new areas and mates in June and July, then lays its eggs in August. The larvae feed just inside the bark in the fall, then overwinter as pre-pupae before hatching into a new generation of adults the next spring.

So it's not surprising that the first confirmed sighting of an emerald ash borer in Princeton happened in late July, when one was found in a trap placed near River Road by the town arborist. Previous documentations in the area were in Bridgewater, West Windsor and other towns.

Treatment to Protect Ash Trees

Homeowners will need to decide, over the next year or two, which if any ash trees they wish to treat. The expense of recurrent treatments, and the ongoing benefits of the tree, need to be weighed against the cost of removal. This definitive article recommends treatment of trees if EAB has been found within 10-15 miles, which is now the case for Princeton. Treatment is most effective in the spring, between mid-May and mid-June, just after the tree leafs out. The article confirms the superior performance of emamectin benzoate, the active ingredient in Arbor Mectin and TreeAge. This insecticide may be more expensive than others like imidichloprid, but lasts longer and has a higher success rate. For more on my research on this issue, scroll down at this link to "How to save specimen ash trees".

Natural Predators of EAB

Woodpeckers are said to eat 80% of the EAB, but that's not enough to stop it. There are native parasitic wasps that also prey on EAB, but not in sufficient numbers. Some parasitic wasps species from the EAB's native range in Asia are being introduced (hopefully with a great deal of prior testing to show they won't prey on our native insect species), but I doubt they will influence the arc of Princeton's infestation over the next decade.

An article in the NY Times discusses techniques to stimulate the defense systems of ash trees so that the tree itself will manufacture sufficient chemical defenses to ward off EAB, but again, any practical use is highly speculative.

What's a Dead Ash Good For?

Strangely, there seems to have been no planning at any governmental level to at least put the coming surge in dead wood to use. Talk of sustainability and the opposition to fracking and natural gas pipelines are weakened if we ignore local sources of renewable energy. Lacking wind, we need to turn to sunlight. Solar panels, now essentially free to install, are an obvious option, but for some reason wood is being ignored. Europe has clean incinerators that generate energy from wood chips. Ann Arbor trucked its ash trees to an energy-generating facility in Flint. Unlike the carbon from fossil fuels, carbon from trees comes from the atmosphere, not from underground, so there is no net increase in above-ground carbon when wood is burned. Composting requires considerable fossil fuel for turning and transporting the compost, and decomposition releases as much carbon as burning.

In addition, the EAB invasion is coming just as Princeton's collection of loose yardwaste is being expanded. There is no effective incentive yet in place for homeowners to trim their dependence on this costly program, and the addition of 1000s of ash trees to this already over-burdened collection service could overwhelm the capacities of the public works department and local composting sites.

Possibly relevant, the state compiled this list of "Forest Industry Professionals Accepting Ash Trees".

Previous Posts

The Emerald Ash Borer's arrival in Princeton had been long anticipated. Some fifteen posts on this blog mention it, dating back to April, 2010, when I wrote,

"In Princeton, we will over the next decade likely witness a dieoff approaching the scale of the chestnut and elm dieoffs of the 20th century, as the emerald ash borer, which hitch-hiked to Michigan from Asia in wooden packing crates, continues its spread eastward. There will, in other words, be a lot of gaps in the canopy for the chestnut to claim, if its return is successful." 

That last part, about a resurgent American chestnut filling the gaps as we lose our ashes to the Emerald Ash Borer (EAB), as the previous post about chestnuts shows, was a nice concept but overly optimistic. Here's a particularly extensive post on EAB, in which I included notes from a phone call with the division chief of Forest Pest Management in Pennsylvania, where they've been dealing with EAB for years.

Native Chestnut Update

While the discovery of Emerald Ash Borer in Princeton several weeks ago cast a big shadow on Princeton's most numerous tree, there's another shadow, growing larger every year, that's reason for hope. That would be the shadow behind this native chestnut tree growing at the Textile Research Institute (TRI) in Princeton. Planted just five years ago, it's now fifteen feet tall, well on its way to taking its place among the oaks towering behind it.

The protective collar around its trunk is beginning to unzip as the tree gets too big for its britches.

This marks the first year it has bloomed, though there may not be any nuts for lack of pollen from other trees. In future years, a less precocious companion planted nearby may catch up and provide that pollen.

These chestnuts, which are really 15/16th native, with some asian genes mixed in to aid in resisting the chestnut blight that laid this species low a century ago, were planted by Bill Sachs, a local nut tree expert who has planted chestnuts and butternuts in a number of locations in town. Butternut is another native tree much reduced in numbers due to an introduced disease.

Below is Bill's status report, from an email. It shows how much persistence and resourcefulness is needed to bring back a species, with a touch of serendipity now and then:

"Yes, I know the one chestnut at TRI flowered this year but there may be no nuts for lack of a pollinator. That tree was two year-old bare rooted stock when planted in 2010. Pretty precocious. Same generation as the ones we planted at Mountain Lakes (there are no healthy survivors left there) and on the Princeton Battlefield (two survivors, one of which has blight). This fall and spring, we may try to inoculate the trees that have blight with the virus that causes hypovirulence. 

There are three planted butternuts at TRI, all pretty close to one another. Two of them have been surrounded by blackberries and other brambles that need to be cleared. Will do that this fall… may need to rent a brush cutter.

Also, discovered a ‘new’ native butternut at ML with a few nuts on it. Been walking past it for years and this is the first time I noticed it because I happened to be looking up into the surrounding crowns to assess the health of the ash trees along the trail."

Bill

Where Trees and Summer Wildflowers Cohabit

Since I gave such short notice about the canal walk tomorrow, I'll offer this virtual tour. Along the DR Canal towpath, just west of Harrison Street in Princeton, there's a nature trail loop. Most people head to the canal with a bike or running shoes to clock some miles, but for those who want to take in their surroundings, the winding, mowed trail offers a lot of wildflower interest this time of year.

While most habitats hereabouts are either dense forest or open field, the trail loop is more of a glade or savanna, with scattered trees offering many gradations of shade and sun to please the eye and meet the varied needs of diverse wildflowers.

Most of the trees along the winding trail are oaks--some planted long ago by the university when this strip of land was tended as an attractive entryway into campus. Oaks tend to have thick, fire resistant bark that can survive the sorts of periodic fires that once would have sustained open woodlands such as this. One of the oaks is a bur oak, uncommon in NJ but famed in the midwest for the bur oak savannas it lords over with its dark spreading limbs contrasting with the deep green obovate leaves that remind me of bison. Many of these savannas have been restored using prescribed burns.

Here's the wildflower that led to the creation of this mini-preserve and nature trail. The cutleaf coneflower has a rosette of leaves at its base. At some point around 2006 I was walking along the towpath and noticed these basal rosettes, which were surviving what were almost weekly mowings at the time. There were many of these clumps scattered throughout the broad area between Carnegie Lake and the towpath, all of which were getting mowed down before they could bloom. It seemed a waste of natural "talent", so I contacted the DR Canal State Park staff, and they agreed to reduce mowing to once a year in that area. There was a bit of a complication because the land is owned by the university, but they were amenable as well. The show of cutleaf coneflower that first year was spectacular.

Seeing the attractive result, the park staff later added a trail and a sign. My role is to send a reminder in late winter to make sure they mow before spring growth begins. Less mowing, more wildflowers--all in a day's rest.

To the right of the sign is a patch of native switchgrass--a tallgrass prairie species that propers in the east as well and is sometimes planted for ornamental purposes.

There's also a patch of knapweed, a nonnative which appears to be Tyrol's rather than the highly invasive spotted knapweed that's moving east from the midwest.

There's a plausible cause and effect here, given that the larvae of ladybugs are voracious consumers of aphids, numerous on the underside of this common milkweed leaf.

Deertongue grass, another native grass that is sometimes used as an ornamental, for instance in the raingarden in front of the Whole Earth Center, prospers along the trail.

The various species of goldenrods are just coming on. Goldenrods get wrongly blamed for being allergenic, because they bloom at the same time as the inconspicuous ragweed.

Some benches were donated to provide restful views of the rowers laboring away on Carnegie Lake.

If you take a closer look at the shore, you'll see yellow pond lilies, lizard's tail and rose mallow hibiscus.

It's really gratifying to see that wildflowers are growing more numerous under the state park's annual mowing regime, with lots of ironweed elevating above the other vegetation,

and expanding patches of Joe-Pye-Weed. This species has hollow stems that provide homes for the local insects.

At one point on a bright morning walk last weekend, I had to stop for a moment, take in the majestic oaks, the bountiful wildflowers extending down the long corridor of the winding trail, a downy woodpecker busy on a limb overhead, insects feasting on the nectar--and realize that we actually did accomplish something here that is lasting, and without spending a nickel. A change in management released the native growth force that had been there all along. Managing with nature rather than against it brought better results with less work.

One fun aspect noticed this year is that the mowing crews appear to be getting creative with the trail mowing, adding attractive lookouts,

and a new circular clearing. Not sure what the purpose of this one is, but it could well serve as habitat for low-growing species that can't compete where there's only one mowing per year.

A favorite sedge, fringed sedge, grows along the trail edge here and there.

Another favorite: wild senna, which in this photo looks a bit like a beehive hairdoo wig that's been in the attic too long. The seedpods are forming below the last few blooms at the top.

Showy tick trefoil is another legume that forms pods quickly beneath blooms higher up. Anyone heading off trail may find these on pantlegs after the walk.

Sticking with the theme, pokeweed berries form lower on the stalk, with flowers higher up.

Pokeweed is usually considered too rambunctious for a garden, but is very attractive and at home in this floodplain.

The long pods of Indian hemp, which is related to milkweed, not that miracle plant hemp, which still remains tragically illegal to grow in the U.S.

This native Clematis virginiana has toothed leaves, while the non-native Clematis autumnalis sometimes found in gardens has smooth-edged leaves. Both can be highly invasive in a garden, popping up in new, undesired spots in the yard.

A really bad actor is this non-native porcelainberry, with leaves and viney growth habit reminiscent of wild grape. Its berries turn white, blue or pink--very attractive but avoid the temptation of picking them and transporting them elsewhere. You can see this kudzu wannabe's over-the-top aggressive growth behind the Clark House at the Princeton Battlefield, and it's been colonizing new areas of Princeton. In past years, it looked like it was going to overwhelm all the wildflowers along this trail, but this year the balance is better for some reason.

The elderberry bushes were getting mowed down each year, which kept them from blooming and making berries, so I've started tagging them to alert the mowing crew in late winter to mow around them. Little interventions like that can make a big difference, simply by making it a little easier for the native growth force to do its thing.

The trail got windier, and actually more interesting, after the stiff winds of Hurricane Sandy, when many trees fell and the trail was mowed to circumvent them.  

Jewelweed is a common annual whose tubular flowers attract hummingbirds. Try touching the swollen seedpods to see what happens.

The trail loops back to the towpath. Walking back towards Harrison Street, you'll see the elephant-ear sized leaves of a Princess tree (Paulownia) that gets cut down each year or two by a different crew that's responsible for keeping vegetation controlled along the canal itself.

Climbing hempweed--that's not related to hemp either--is a native vine common along the edge of the canal.

Sometimes it has parasitic dodder mixed in.

That's the hike. Oh, I forgot the figwort--a tall wildflower that only a botanist could love. It's not blooming in the photo, but the flowers are so small that you're not missing anything. I've only seen maybe five plants of this species in all of Princeton, so it's special to see it has survived another year on this island where land and lake, tree and wildflower, native growth force and human tending, all cohabit so pleasingly.

Canal Wildflower Walk This Saturday

I'll be leading a walk along the canal this Saturday, August 22, starting at 8:30am. Morning light adds to the freshness of this landscape. We'll meet along the towpath just west of Harrison Street, where there's a nature trail sign. All are welcome.

Wildflowers have been at their peak this past week--a perk for all of us who haven't fled Princeton in August--and there should still be a good show this weekend. We'll focus on the nature trail loop that I "catalyzed" back in 2006, when I alerted DR Canal State Park staff that there were some wonderful native wildflowers that were getting mowed down between the towpath and Carnegie Lake. The park staff reduced mowing to once a year (less work!), added a broad, well-mowed trail that connects in multiple places to the towpath, and the native flora has responded by growing in greater abundance each year.

The nature trail threads through Princeton's closest approximation of an oak savanna, where there are enough openings between trees to allow summer wildflowers to prosper underneath. All of these Hollow-stemmed Joe-Pye-Weeds are facing north, towards a gap in the tree canopy.

We'll see how natural and cultural influences--from canal building to hurricanes--have combined to shape this diverse, dynamic floodplain habitat.

Parking: There are two small parking lots at either end of the Harrison Street bridge. More distant parking is in the Lake Lane area, just off Harrison St. north of the lake, and at a lot on Washington Road just south of the towpath. If you get there late, it should be easy to find us along the trail loop. This link should take you to a map.

High Season for Floodplain Wildflowers

This is high season for floodplain wildflowers in Princeton, the sorts of native plants that also thrive in raingardens. The first rose mallow Hibiscus (H. moscheutos) appeared one morning about three weeks ago like a big eye looking out from the backyard garden. They're still going strong, and must be impressive along the banks of the Millstone River, easily accessible by boat, upstream of Carnegie Lake.

I planted one in a client's backyard swale, and it delighted them with its first bloom a few days ago, only to be later bombed by a branch from an ash tree towering overhead. The large branch, which landed squarely on the newly planted garden, appeared to be perfectly healthy, and there was no recent weather to point to as cause. It was a freak event, the garden rebounded, but still there was something uncanny about the timing.

Other floodplain wildflowers in bloom are wild senna (pictured), Joe Pye Weed, cutleaf coneflower, and cardinal flower. Boneset, whose bloom marks the climax of pollinator activity, is just opening up.

A couple other native species that haven't been seen growing wild in Princeton but add to the blooming power of our backyard is Culver's Root (past bloom by now) and cup-plant--a robust plant in the Silphium genus that towers over all others, except of course, the trees.

Roosters in Princeton

To all the voices that hold forth in Princeton, add some cockadoodledoos. I had heard that there were some roosters among us--a painter who grew up in South Africa told me a few years ago the sound made him feel at home--but had not heard any until this past month. One was east of Harrison Street a few blocks, which I took the liberty of photgraphing. The other is within crowing distance of town hall.

The legality of having poultry in Princeton comes up now and then. There are some ordinances left over from the borough/township days that were contradictory. The straightest answer I got when I looked into it was from the town's former animal control officer, who said they are legal, or at least tolerated, as long as the neighbors are happy. It was my impression that roosters were not permitted, but it may be that the happy neighbor rule determines whether any ordinance, written or improvised, is enforced.

Though a rooster would never tell you this, they aren't needed for egg production. We'd have to ask the owners if they intentionally bought roosters. Chickens are sold when just a couple weeks old, when sex identification can be tricky. Famed Princeton resident Joyce Carol Oats said, in response to a question I asked after she read from her memoir at the Princeton Public Library, that chickens in general and roosters in particular were an important part of her childhood.

We currently have one Pekin duck and four Aracana chickens. The chickens are quiet sorts, but the duck can speak out at various points during the day, calling for more food, or announcing to the world that it is now waddling across the lawn. Neighbors tell me they like the sounds, as a rural salve for the traffic noise on Harrison Street. The droppings disappear into the grass, and any scratching the chickens do leaves our flower gardens undisturbed.

As pets, they are low maintenance. Clean the coop now and then, make sure there's food and water in the backyard, open the coop in the morning, close it at night. We free-range them, meaning they have the run of the fenced-in backyard. We have lost a few to hawks over the years, usually in late fall and winter when wild prey are less available and the birds have less cover. It can be traumatic, but it brings us up against important issues of life and death, pet vs. livestock, quality of life vs. longevity, risks and rewards, and our relationship to the wild animal community that also calls Princeton home. Interestingly, it's the white birds that the hawks have left alone, as if hawks, too, associate whiteness with some otherworldly nature.

The chickens have shown no desire to fly away, and the duck is so heavy that she has even less chance of clearing a fence than the contraption the claymation chickens built in the movie Chicken Run. The chickens lay eggs most days, and the duck produces one egg per day like clockwork. An Italian neighbor, who barely speaks english, knocks on our door periodically, seeking a dozen duck eggs for her Chinese daughter in law. Perhaps the greatest pleasure, in a town where yards go unused and can tend towards sterile display, is seeing how much the birds appreciate and take full advantage of what the yard has to give.

Though a rooster might help protect the hens, our "guard duck" performs a similar role while producing copious amounts of eggs. In addition to her big, boisterous voice during the day, at dusk she assumes her post just inside the coop door, her beak a formidable weapon ready to unleash against any would-be intruders.

A previous post gives more details, and local sources of chicks. Rosedale Mills told me they were selling chickens beyond the optimal April/May season, though it helps if they are fully grown by the time winter comes.