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.

Contrasting Walks At Island Beach State Park

Five weeks ago, at the Barnegat Beach Buggy Access at the far end of Island Beach State Park, the choice was easy. To the south stretched a beach fashioned by wind and ruled by birds.

To the north, tire tracks and traffic.

Someone, or some governmental agency that values birds and the people who want them around, had drawn a line in the sand beyond which no vehicles could go, and we gratefully stepped across it into the car-free, bird-friendly zone to hike south along the beach towards the distant lighthouse.

The first impression, after a gap in beach visits of several years, was the wonderful, salty smell of the sea that must touch memories deep in the DNA of who we are and where we come from.

This is what the Jersey beach can be on a Monday in late July. A threat of rain surely helped make the beach ours for the afternoon.

The plovers congregated in masses some distance in from the surf.

The seagulls, terns and plovers had the run of the place, each with its own approach to harvesting the ocean's offerings.

We thought this gull had caught a crab, but it turned out the crab, or was it a clam, had caught the gull. It hobbled around, unsure what to do about the prey's iron grip.

Which way's the lighthouse? That way, said the shadow in the sand.

Cheers for the planters of beach grass, which in the post-Hurricane Sandy appraisal proved more effective than hardened walls at protecting the interior of islands.

Where the entry for vehicles was cut in the dune, you could see the impressive root structure under the soft waves of green.

After the walk, a quick swim and some cloud bathing. The rain finally came on our drive back.

A return trip this past week to the same stretch of Island Beach State Park revealed a far different scene. The line in the sand was gone, and the plovers were displaced by a fleet of pickup trucks, their front bumpers bristling with fishing rods projecting high in the air, and 4X4 truck beds stuffed with beach chairs and dinner supplies. Flags waved above these beloved machines,

and fishing rods were planted in the sand, though for what purpose wasn't always clear. Some fishing rods had no line extending out into the ocean. Some had no line, period. A friendly fisherman explained that fishing rods were required for anyone parked along that stretch of beach. He himself had been fishing for two years, since retiring, and had yet to catch a fish. It's a lifestyle choice, and he and his wife appeared to feel lucky whether they caught fish or not.

Though we could still enjoy the walk, it felt like we had entered one of the myriad car commercials that relentlessly seek to lodge the internal combustion engine deep in your psyche, so that you define yourself by the size and make of your iron steed. Here was nature to run roughshod over and be laid claim to with flags planted in the sand.

Ironies abounded. A beach torn up out of love for the ocean. Fishermen with little interest in catching fish. A laying claim to the land using vehicles that hasten the rising ocean's next storm-fed eviction notice. Using the American flag to ornament a lifestyle that will ultimately sacrifice much of the nation's coastal real estate. Wasn't the nation founded by people who cared about the future, and did all they could to insure the nation's perpetuity? And weren't we, by driving to the beach, part of the same bargain with the devil? How long will widespread denial and governmental paralysis keep us in this ethical bind, when the free energy of wind and sun are all around us?

We need a new saying for our time, that expresses how the lifestyle people value is threatened by resistance to changing its energy source: "The more things stay the same, the more things will change."

If the gulls had thought the beach was theirs, they were clearly mistaken.

Still, there was an ocean breeze, and an air of relaxation and enjoyment. The line in the sand was displaced but not eliminated.

Shadows lent beauty even to ruts in the sand.

And there was peace in seeing the next generation grown up, walking in peace and affection, along that wonderful ribbon where land and water gather to meet the sky.

August Bird Disappearance Solved

Two weeks ago, I received an email with the news that the water birds had disappeared from Mountain Lakes Preserve. Might something have been applied to the water to remove algae, with unexpected results, or were geese, ducks and herons simply imitating the general human exodus from Princeton in August? My contacts at town engineering and Friends of Princeton Open Space knew of no chemical applications.

Carnegie Lake, too, was empty of waterfowl, other than a couple great blue herons. One heron flew across the lake, flushed another near the opposite shore, chased it a short distance, then returned across the lake, flying low, its wingtips touching the water.

Smoyer Park's pond also was clear of geese. Had they finally taken note of the signage?

Maybe the fisherman's dog had scared the geese away.

The dog, upon closer inspection, turned out to be 2-dimensional, a metal dog profile placed there by the company contracted to periodically (futily?) scare the geese away. The fake dog looked to be faking out the geese, but the fisherman was skeptical, and told me the geese will soon be back.

Some responses from people in the know, plus some internet research, helped make sense of it all.

Plainsboro Preserve director Nancy Fiske forwarded a response from Scott Barnes, head of New Jersey Audubon's All Things Birds division:

"Most waterfowl tend to molt in late summer and are flightless for a brief period of time, during which they are secretive. I've seen typical numbers of geese around locally in the last few weeks; it may just be they've moved of a particular water body in Princeton. Geese will often change habits and feed at night around the full moon. As for herons and egrets, late summer is a time of wandering, where both adults and juveniles will move about from place to place taking advantage of local food sources and concentrations of fish at ponds/lakes with lower water levels."

Stephanie Fox, naturalist with Delaware and Raritan Canal State Park, added, 

"as for Herons, I believe they are still able to fly, but just not so efficiently, so they also try to hide out in less conspicuous areas until they have their full set of flight feathers."

That could explain why the great blue heron seemed to be struggling to stay above water, and perhaps it was acting territorially towards a young whippersnapper encroaching on its part of Carnegie Lake.

For those uninitiated in the ways of birds, like me, some general info about molting is at this link. The distinction between the "sequential molt" that most birds undergo, and the "simultaneous wing molt" characteristic of ducks and geese, can be found here. 

Thanks to Elliot for alerting me to this seasonal exodus. It would be interesting to find out where the birds go to be safe during molting, and whether it's one place or many.

Towpath Walk This Sunday, Aug. 28, 8:30am

Time for the annual nature walk along the loop trail next to the towpath. We'll meet at 8:30a this Sunday, August 28, along the towpath just west of Harrison Street, where there's a nature trail sign. All are welcome.

We'll catch the overlap between August and September flowers, as JoePyeWeed, ironweed and cutleaf coneflower transition to goldenrods. The wildflowers were getting mowed down until 2006, when I was able to talk DR Canal State Park staff into cutting back on the mowing. The park staff reduced mowing to once a year (less work!), added a broad, well-mowed trail that runs parallel to the main 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.

Sensational Year for Floodplain Wildflowers

If only buildings loved this summer's heavy rains as much as these floodplain wildflowers do. Wild senna has never put on a show quite like this.

A variant of Hibiscus moscheutos is turning on the pink.

Joe-Pye-Weed is flourishing.

Just one stalk of a 9 foot high cupplant would be enough for a bouquet.







The cutleaf coneflower and late-flowering thoroughwort combo has turned the backyard yellow and white. And the pollinators are just lapping it up. A number of factors make these lowland wildflowers easy to grow. The soft ground and the exuberant growth of the desired plants makes weeding easy, and the species shown lack the capacity to spread with rhizomes or stolons, making it much easier to keep the garden in balance.

Capturing Runoff at the Shopping Center

What is soft rush, a wetland species, doing outside the entrance for Ace Hardware at the Princeton Shopping Center? Look up and to the left and you'll see the awning that spills lots of water onto the walkway during rains. The concrete absorbs the impact and the water then makes haste to the bed of rushes, where much of it is absorbed. Pretty clever. Soft rush is evergreen, so should provide some color even during the winter months. We'll see how it weathers the salt and snowplows that stray off course.

Just down from the rushes is a parking lot island. In the past, these islands would have been built higher than the surrounding pavement, and spurned the runoff. But some of the new islands have notches in the Belgian Block curbing where runoff can enter, seep into the ground and feed the plantings.

All of this means a little less of the shopping center's massive, unfiltered runoff goes thundering into Harry's Brook, a few hundred feet away where the brook becomes a brook in Grover Park.

See a previous post that compares the shopping center's parking lot with a more advanced design at Westminster Choir College.

Check Your Viburnums for Imported Leaf Beetle

The list of destructive, imported insects affecting Princeton is getting longer. Most people are aware of the gypsy moth and the Emerald ash borer. Add the Viburnum leaf beetle, which skeletonizes Viburnums in people's yards and in the wild. A post in May last year documented the larva chewing on a Viburnum in Princeton's Harrison Street Park. I killed every larvae I could find, and haven't seen a recurrence this year. But badly eaten leaves on a Viburnum in a friend's yard in nearby Lawrence this summer mark a second sighting, this time with damage coming from the adult beetle.  

Here's what appears to be an adult on a Viburnum commonly called highbush cranberry.

They do a thorough job of it. Completely skeletonized shrubs seen in Pittsburgh years ago were a chilling omen for what could happen throughout the eastern U.S. It should be noted, in this age when so much focus in the news is on intentionally destructive behavior, that the greatest damage to our world is being wrought completely without malice, as insects and diseases hitchhike on transported nursery stock, and the products of combustion slip silently, invisibly from our exhaust pipes and chimneys.

An arrowwood Viburnum (V. dentatum) in my backyard is showing early signs of an infestation. These are two of the most susceptible species of Viburnum. The most striking incidence of arrowwood Viburnum in Princeton is in low woodlands along the DR canal. Despite growing in deep shade, it can have surprisingly showy clusters of white flowers in the spring. Sad to think those spring vistas could become a thing of the past.

If you check any backyard Viburnums you may have and find early signs, you may be able to limit next year's damage with some of the techniques described at this link.

The blackhaw Viburnum, our most common Viburnum in the wild, is less susceptible.

Native Plants Featured at the Olympics

The Olympic opening ceremonies in Rio included a big surprise. After some spectacular visuals and choreography with a cast of thousands, the stadium darkened and a solitary boy walks across the stage. He encounters, of all things,

a plant, and thus starts a segment on climate change, with maps showing the coastlines of the world that will be swallowed by the ocean, the shrinking ice cap, and a visual conveying the warming atmosphere over the past century.

Most people think of plants as mere ornament and background for human endeavor, but here was a plant, a Brazilian native plant, no less, front and center, drawing the spotlight. It's one of the great paradoxes, that humanity's first line of defense against the planet's greatest threat is not our militaries, but, of all things, plants. They'll never win the 400 meter, or dazzle on the parallel bars, and many kids graduate from high school knowing little about them, but as brilliant chemists that tirelessly eat carbon dioxide, plants have everything to do with winning the marathon to keep our planet livable for generations to come.

And there they were, later in the evening, next to the flagbearer for each nation entering the arena, native plants of Brazil being carried by a child. A whole forest will be planted, with one plant for every competing athlete. Symbolic, to be sure, contrasting starkly with the environmental realities in Rio, but moving nonetheless.

In this photo, the plant fronting the U.S. athletes is a green flash on the right, with Michael Phelps bearing the flag in the background.

It felt like a gamechanger, as if the world is making a pivot and starting to get its priorities straight. That plant in no way compensates for the human combustion-fest of bright lights and fireworks, but at least it's there, with its humble, heroic chlorophyll, unmatched in its chemical prowess, to remind the athletes where their inhales come from and their exhales are headed.

Before and After the Flood at the High School Wetland

Many have seen the video of the extraordinary flooding at Princeton High School on July 30. As something of a citizen "activator", and high school parent, I'm meeting with school and town to help give momentum to a lasting solution to prevent future flood damage to the school.

I hope the school's basement and performing arts stage prove as resilient as the wildflowers in the ecolab wetland, which happen to be in full bloom. First photo is a "during" shot, showing the Joe-Pye-Weed and Rose mallow hibiscus sitting in five feet of floodwater.

This second photo shows the plants the next day, happy as clams, as if refreshed from a nice long bath.

This is a great time to stop by and take a walk around the perimeter of the wetland, and maybe catch the sunset in the big sky over the ball fields just on the other side of the performing arts wing from the wetland, on Walnut Lane.

Towpath Nature Trail Loop:
Another great place to see these beautiful summer wildflowers is along the nature walk created and maintained by the DR Canal State Park crews. Get on the towpath at Harrison Street and look for the Nature Trail sign. A virtual guided walk can be found here. This link should take you to a map.