Deceptive Weeds

This time of year, you may see some plants rising in the garden that look like they have potential. Something about their form makes you hesitate to peg them as weeds and pull them out. Maybe, you think, it's better to wait and see if all that growth yields a substantial flower. Here are some weeds that have fooled me into a wait-and-see at some point in the past.

Pilewort has a thick stem and strong vertical intent. It will give you pause because it looks like it's headed somewhere, which, it turns out, is mostly up. All that vertical ambition climaxes in a gangly jumble of small flowers that attract pollinators but lack color. The name comes from the white seedheads that look like cottony stuffing for a mattress. If left to scatter, they will give rise to many more plants to be pulled the next June.

Pilewort - Erechtites hieracifolia - Aster family

Willow herb has a nice form, but can get weedy in wet soil, and the flowers are too small to create a visual effect.

Northern Willow Herb

Epilobium glandulosum

A member of the borage family, this plant, too, has an attractive form that looks like it could generate an attractive flower. If you leave it in, you'll end up instead with a bunch of stickers to pick off your clothes. Appropriately enough, it's called stickweed.

Stickseed
Hackelia virginiana
Borage family (Boraginaceae)

Mugwort has a nice resiny odor to the crushed leaves, and looks like it could grow an attractive flower, but doesn't. Instead, its capacity to spread underground to form dense masses makes it a threat to any garden. The cardboard box in the photo will be laid flat to smother the weeds.

There are Bidens with very showy, sunflower-like yellow flowers that bloom along Quaker Road later in the summer. And then there is the Bidens species that somehow made it into my garden, which produces flowers that lack any show at all. We had the showy species flourishing along a bike trail in Durham, NC. Gorgeous, but it grew so enthusiastically that it started obscuring the trail. Though it reaches great size, Bidens is an annual and can be easily pulled.

Even though I know that lambs quarters doesn't make showy flowers, the plant fools me each year into thinking I'll get around to eating its tasty and nutritious leaves. Generally, I forget, but this year my younger daughter used some in a red lentil soup that was delicious. An annual, lambs quarters can be abundant one year, hard to find the next. Like pigweed, it can get enormous in abandoned plantings.

When pulling weeds, pull low and slow, so the roots come out. Weeding teaches the gardener to be strategic. Humans tend to have little time, while the weed is dedicated to growing and spreading 24/7. Best to weed when the soil is soft, to get the roots, and before the weeds go to seed. To keep them from rerooting, best to drop them where the roots won't touch the ground, and where the sun can dry them out.

Entomologist Rachael Winfree Offers Advice on Catering to Bees

Some time back, Rachael Winfree, an entomologist at Rutgers, generously agreed to meet with us at the pollinator garden we're creating at Herrontown Woods, to discuss ways it might better fill the needs of bees. For an hour, she poured out information while I scrambled to take notes. More can be found at her website, at the bottom of this post.

DEAD WOOD: Her first thought was that she liked all the wood strewn about, in the form of trees felled by wind and ice storms over the past ten years. The bodies of trees live a long life after death, providing a home for all sorts of insect life. Fallen trees are one of the places bumble bees make their nests underneath.

SOIL: She liked less the soil--mostly heavy clay. The many kinds of bees that build their nests underground prefer looser, more sandy soil. Perhaps we could bring some sand in to lighten up some areas, she suggested, or dig up the soil here and there to make the bee's job of digging easier.

SLOPING GROUND: Slopes would be good, too. Water runs off a slope better, so there's less chance that the bee's underground home will be flooded. Our pollinator garden has no hills, but it does have the hillocks made when a tree is uprooted. The rootball angles up into the air, leaving behind a hole in the ground with slopes on all sides. America, it is said, was very lumpy back before western settlement, as each tree over the millenia would eventually fall, its raised rootball leaving a depression.

XERCIS SOCIETY: She mentioned the Xercis Society and its website on multiple occasions. She's on its board, and thinks it's one of the best sources of ideas for creating habitat for insects.

WASPS VS BEES: Wasps visit flowers not to collect pollen but to sip enough nectar to get through the day. They are therefore poor pollinators, since they don't collect pollen and therefore are less likely to spread pollen from one flower to another. To reproduce, they prey on other insects, which they collect and use to nourish their young.

BEES ARE VEGETARIANS: Bees are essentially vegetarian wasps. They use the protein in pollen to feed their young, collecting a bunch of pollen and then laying an egg in it. Different bees carry pollen on different parts of their bodies. The classic honey bee, the cow of the bee world, not native but widespread in the service of agriculture, carries pollen on the back legs, as do bumblebees. One bee carries pollen on its belly, which is very cute to see when one turns the bee over.

SOCIAL VS SOLITARY BEES: Social bees, such as honey bees and bumble bees, are in the minority. Most types of bees are solitary. These types are very unlikely to sting, because stinging is a very dangerous activity for a bee, and a solitary bee is on its own. Bumble bees and other social bees are "on the wing" longer than solitary bees, meaning that they are around all summer rather than for just a couple weeks.

BEES IN DECLINE?: Though the news media has been reporting that bees are in decline, Rachael contends that there isn't all that much evidence to back that up. There are no long-standing studies of bee numbers to reference. Complicating any effort to tally bee numbers, there are only three taxonomists who can identify all 160 or so species of native bees in New Jersey. (I didn't catch the names, but two of them may be John Ascher and Jason Gibbs. When googling John Ascher, I came across this very useful looking manual: How to catch and identify bees and manage a collection) Bees, unlike plants, must be killed in order to be identified, and though some of that is necessary for research, it's not necessarily an activity entomologists want to promote. Bees may actually benefit from the habitat fragmentation that comes with suburban sprawl.

SPECIALIZED BEES: I had wondered if there are specialized bees that depend on a particular plant species that we could then plant to help that bee species. She mentioned two to get me started: a bee called Andrena erigeneae that feeds exclusively on spring beauty (Claytonia virginica), and the Rose-mallow Bee (Ptilothrix bombiformis), which has a black velvet appearance and feeds on Hibiscus. (I found this informative article that lists many others: https://vnps.org/specialist-bees-need-special-plants/)

SMALL CARPENTER BEE (Ceratina sp.): a common bee around here.

NESTING: Bumble bees nest under logs, or at the base of bunch grasses.

MOBILITY: Small bees fly only a couple hundred feet.

PLANTS TO ATTRACT BEES: sweet bergamot, lavender, mountain mint--especially Pycnanthemum tenuifolium

MORE INFO: Her website has useful pdfs, including a primer on New Jersey bees.

Repopulating the Community With Native Wildflowers

My younger daughter Anna recently returned from a year in Bolivia, and since she loves to walk, we headed out across town towards Mountain Lakes. It gave me a chance to check out, or check in on, some of the plantings I've been involved in creating over the years. It was surprising how many we encountered along the way. There are the rain gardens adopted at the Westminster parking lot, plantings on both sides of the high school, a couple gardens around Mountain Lakes House, and then on the way back we stopped by the courtyard behind the Community Park Elementary, where I recently helped a bit with a garden planted by students under the leadership of Georgette Stern. Those are projects west of my house. Extending eastward are plantings at the Whole Earth Center, Smoyer Park and a botanical garden being established at Herrontown Woods.

Since many of the plants now in public places come from my backyard, or in many cases "through" my backyard from wildflower seeds collected from native populations along the canal, there are recurrent themes.

A pollinator flying around town will encounter these bottlebrush buckeyes in my yard, at Mountain Lakes House, and now at the botanical garden at Herrontown Woods.

These backyard clouds of tall meadow rue were first found along the canal, then traveled to my yard and from there to the various gardens around town. The new populations are particularly important because the original patch along the canal is being grown over by invasive porcelainberry vine.

Virginia sweetspire came from a nursery, but creates suckers that can be easily dug and transplanted to public places.

Divisions from these backyard oakleafed hydrangias have also become ambassadors of native beauty in the community.

The richweed in the front left of this photo is a rare native that first arrived in the backyard via a plant rescue from a stream restoration site on the university campus. Though it doesn't have showy flowers, the hydrangia-like foliage makes an attractive massing in a flower bed. Again, the backyard was a conduit, as the richweed's seedlings are now growing at Herrontown Woods.

Some beebalm given to me by a friend mixes with the tall meadow rue from the canal.

Division from that beebalm now thrive at the Herrontown Woods botanical garden, protected from the deer by some fencing.

Sundrops, here mixed with deer tongue grass--a common native grass in local floodplains--also made the journey from backyard to botanical garden,

as did cupplant, a giant wildflower here catching rain in its "cup." This is probably the tenth or twentieth generation from the original plant rescued in 1994 from next to a dumpster behind Mark Twain's house in Hartford, CT.

Fox sedge is a common local sedge that has an attractive shape that works for informal gardens.

A more recent find is purple milkweed (distinct from common, swamp, green, butterflyweed, etc.), a few specimens of which are now traveling from their original location at the Veblen House grounds to begin growing elsewhere in town.

Others have yet to travel, like black-eyed Susan,

and Queen of the Prairie (Filipendula rubra), a native I've never seen growing in the wild, given to us by a friend our first full summer in Princeton, when the 17 year cicadas were having a look all around.

The purpose of this post is not to encourage people to dig up plants from their gardens and spread them indiscriminately throughout town. Given how weeds can travel in dirt, I'm careful to introduce to new areas only seeds or bareroot plants, with a strong preference for local genotypes rather than bred varieties. The goal that began this process was to make isolated remnant populations of this or that native species less isolated and more resilient by starting new populations in auspicious conditions elsewhere in town.

There's a long-standing irony that the wildflowers native to an area are often the least encountered by people living in suburban landscapes dominated by non-native plants. This process of seed collection, division and transplanting, natural to a gardener, can help bring back some native diversity in the community, for people as well as pollinators to enjoy.

Sunday, June 23: Veblen Birthday BBQ

This Sunday, June 23 from 2-5pm, the Friends of Herrontown Woods (FOHW) will be hosting a birthday BBQ on the grounds of Veblen House at Herrontown Woods. Food, drink, games, and socializing, to celebrate the 139th birthday of mathematician and visionary Oswald Veblen. He and his wife Elizabeth donated Herrontown Woods as Princeton's first nature preserve in 1957.

We will provide a grill, hotdogs, hamburgers, and refreshments. Potluck offerings of food/drink are encouraged.

In honor of Veblen's mathematical work on trajectories, we'll have places to play volleyball, badminton, and we'll set a pingpong table up in the Veblen driveway. Playing pingpong in a natural setting could put a new spin on things.

We have some demonstration raingardens to show off, with some plant labels added. There will be some painting activities for kids.

PARK IN THE VEBLEN DRIVEWAY AT 474 HERRONTOWN ROAD.
Or park in the main Herrontown Woods parking lot off of Snowden Lane, and walk up to the house (scroll down at this link for map). Facilities if needed are a short drive away at Smoyer Park.

A Botanist's Revisiting of Central Park

Enter New York's Central Park across from the Natural History Museum, and you're likely to come upon one of the giant rocks where kids climb. For a parent whose kids have grown, it's a chance to gaze at the changing skyline in the distance (taller, skinnier), and remember back some distance to that parental mixture of worry and delight as a young daughter explored the sometimes precipitous contours of this massive boulder.

For many people, this spot may not offer much beyond rock, water, and skyline softened by an undifferentiated sea of green foliage.

But for a botanist and wild gardener, this place evokes so much more. That tree on the left in the first photo is a serviceberry (Amelanchier) that in early June is loaded with ripe berries. I gorged while the incurious streamed by on their way to rocks and water.

A massing of cup-plants under a sycamore tree brought back memories of where I first encountered this towering native wildflower, growing untended next to a dumpster in the parking lot of Mark Twain's historic house in Hartford, CT.

The sight of royal fern (Osmunda regalis) brings back memories of all the other places I've seen it, whether planted in my yard or growing wild, back in the depths of Herrontown Woods.

This Virginia sweetspire looks very much like the one in my front yard, but with a grander backdrop, and brings back memories of the one time I saw it growing in the wild, along the banks of the Eno River in North Carolina.

These rosemallow hibiscus are offering little in mid-June to catch the untrained eye, but recognizing them without flowers links Central Park to my backyard, the edges of the Millstone River headwaters, and everywhere else I've seen this native hibiscus growing. Familiarity with the plant in all stages also makes it possible to "see" the big, broad flowers that will come in July. For a seasoned wild gardener, that is, a gardener who has been through all the seasons with this or that plant, the present is enriched by the past and future it holds within it.

The community of plants near the climbing rock--native shrubs and wildflowers that thrive with wet ground below and sun above--is what we've propagated into many areas of Princeton, but Central Park adds the framing of the skyline, rock outcroppings and water. To see it there, or in the parks of Chicago during a recent visit, is to bear witness to a recurring community gathering, each member with its quirks. Buttonbush, with its buttons of forming seeds, is in this particular photo. Many others are not shown, like Joe Pye Weed, lizard's tail, cutleaf coneflower, Helenium, New England aster, cardinal flower--their coevolution in the wild here emulated in a park.

So many steps it takes, to raise kids or raise an enriching awareness of plants, which in turn brings meaning and memory to every new step taken.

A Few Spring Surprises

Watch spring unfold for enough years and it can start to get predictable in a Groundhog Day kind of way. One group of bloomers segues into the next, year after year. There's a theater piece I wrote called Spring Training, that imagines how Spring's trainer, charged with getting Spring in shape for the annual run-through, would react if Spring decided to go rogue and change the order of flowers on a whim. That hasn't happened, far as I know, despite all the changes underfoot and overhead due to our chemical tampering with the atmosphere. Still, this spring has offered a collection of surprises.

A big surprise came a couple mornings ago, when I dared to walk out into the garden and search for strawberries. Disappointment had been a predictable result up to now, as catbirds, slugs, and who knows what else would claim our berry harvests before we could. True, our past care of the garden had not been marked by a consistent diligence and vigilance, and maybe that was the difference this year. We've paid the garden more attention, and in return it provided a yield of incredibly unblemished berries.

Daffodils in late May? That's what you get, it turns out, when you plant them in March, rather than the previous fall. These were planted by volunteers who came to a daffodil planting party at Veblen House.

Also at Veblen House, the pawpaws are leapin'. There's a saying about transplanted shrubs and trees. "The first year they sleep, the second year they creep, and on the third year they leap!" It's been four years since we planted these. Close enough. Periodic attention has had to be paid to protect them until they are beyond the reach of the deer.

That's Friends of Herrontown Woods board member Victoria Floor providing scale.

My friend Steven who has pawpaws in the backyard had to hand pollinate them to get fruit. This wasn't incredibly surprising, though it's always a surprise when something that's supposed to work actually works.

Steven reminded me that years ago I had given him a "live stake" of silky dogwood. It probably looked a lot like this one--a two foot long late-winter cutting that, in this case, was left to sit in a bucket of water until it sprouted leaves on top and roots on the bottom.

He had planted it in his "lower 40", a wet area that receives runoff from the yard and some sun from an opening in the canopy. Since then, it has quietly grown into a shrub more than ten feet high.

A live stake of elderberry performed similarly.

Another surprise came when Architect Kirsten Thoft reminded me recently that I'd given her some plants for her "stormwater planter", which utilizes and filters runoff from the roof before releasing the rest into the yard. This is a good option for downspouts that empty onto pavement. Plants I noticed: Virginia sweetspire, tall meadowrue, and royal fern.

If there's a theme here, it's that plants and nature in general demonstrate an impressive growth force when given a chance, and a little dose of tending through the years. That's a realization that never loses its sense of pleasant surprise.

Two Snakes Embrace in a Preserved Princeton Farm Field

I recently met with DR Greenway's Cindy Taylor to discuss management of 4.5 acres of farmland preserved by Mercer County. The land is strategically located next to Veblen House and Herrontown Woods, near the corner of Snowden Lane and Herrontown Road. It seemed destined to be added to Herrontown Woods, but was not included in last year's transfer of Herrontown Woods from county to town ownership.

While walking the property we nearly stepped on a couple snakes out mating in their field. From what I've heard and read, there are venemous snakes in northern and southern New Jersey, but not here in the central region. This one, or two, look like something a botanist would call a garter snake. I hope they didn't mind too much our human curiosity.

Up until a couple years ago the land was owned by John Powell, who was manager of the Weller farm before it became Smoyer Park. Each year on his six remaining acres of pasture, John would grow a couple head of cattle, a picturesque reminder of when Jac Weller had a real farm across the road, with bulls that would occasionally escape, prompting a surprised neighbor to call the farm to report that there was a bull in the backyard.

The preserved land includes a small pond that's filled in spring with spring peepers.

The 4.5 preserved acres are as close to a clean slate as we get in Princeton. Do we keep it as pasture with mostly nonnative grasses? Or do we shift it to native prairie grasses and wet meadow wildflowers? Periodic mowing would be needed in either case. Letting it grow up in trees would reduce even further the places where shade-intolerant plant species can grow. Or can it still perform some farm-like function? I showed NOFA-NJ (Northeast Organic Farmers' Association) the site years ago, including the adjacent farmhouse, without success.

Meanwhile, we continue our travel through the 21st century. Ash trees on the neighbor's property succumb to Emerald Ash Borer,

while garter snakes know what to do with a field, even if we do not.

Balance and Imbalance in Nature

Here are two examples of insects eating leaves at Herrontown Woods. One is sustaining balance, while the other threatens the survival of beloved native Viburnums. Why is one insect beneficial, and the other highly destructive? The story begins with the sensitive fern, a beautiful native that graces local wetlands and gardens.

Though we tend to think of ferns as delicate, the sensitive fern is a tough, resilient plant in moist ground, sometimes even showing expansionist tendencies in a garden. The "sensitive" in the name refers primarily to its susceptibility to first frost in the fall.

Typically, the aggressiveness of native plants has been countered through the co-evolution over many millenia of other organisms that can eat them. Any plant that becomes super abundant will in turn provide abundant reward for any organism that develops a capacity to eat it, thereby bringing its population back into balance with other species. That co-evolution takes time, given that plants are brilliant chemists, with many chemical and physical defenses that must be overcome by any would-be consumer.

Since deer generally don't eat sensitive fern and our summers are getting wetter, what might keep it in check?

Recently, while weeding the new botanical garden at Herrontown Woods, I found some young sensitive ferns stripped down to their leaf veins. Sensitive ferns, it turns out, are eaten by several kinds of insects, each attacking a different part of the plant.

The culprit here was a little green caterpillar, most likely a sawfly larva.

Presumably, because I haven't heard of any new, introduced insect ravaging ferns, this insect evolved long ago a capacity to digest and detoxify the sensitive fern's chemical defenses. Any predator that consumes all of its prey will not itself survive, so relationships tend to evolve between predator and prey that are mutually sustaining, and therefore promote balance in nature.

The damage inflicted by the caterpillar is therefore reassuring.

By contrast, the insect damage on this leaf, encountered on the red trail leading up to the Veblen Cottage, was not at all reassuring. It is instead evidence of a radical change coming to Princeton's nature preserves that could largely eliminate several important shrub species from our woodlands and gardens. The leaf is of arrowwood Viburnum, one of three Viburnum species that up to now have contributed flowers, berries, and fall foliage to Herrontown Woods' ecological functionality and beauty.

Their continued presence is now threatened by an introduced species, the Viburnum leaf beetle. Past writings about this invasive beetle on this blog can be found at this link. Arrowwood Viburnum tends to be the first to succumb, followed by mapleleaf Viburnum and blackhaw Viburnum. The insect has the ability to completely skeletonize a shrub. Multiple attacks can ultimately exhaust the plant's reserve energy. I saw a skeletonized Viburnum in Pittsburgh some years ago. Its complete stripping of the plant's foliage was in contrast to a native predator that would tend to do only partial damage, leaving most of the plant alone.


http://www.hort.cornell.edu/vlb/manage.html

Below, from a Cornell University website, is one potential scenario. It suggests that there will be an initial wave of destruction as the Viburnum leaf beetle eats through all the susceptible Viburnums, after which the insect's population will crash, and become a minor pest from thereon, allowing the susceptible species to grow once again. Even if this were to prove true, the introduced pest represents one more shock to the system.

"The viburnum leaf beetle hit us hard in the Rochester area about 15 years ago. During those first few years in which the beetle population peaked most of the susceptible native species like arrowwood, that were growing in wooded areas, were killed. Some landscape plants succumbed to the defoliation then too.

"At that time I would not have recommend planting a susceptible species like the Cranberry bush viburnum. Now however the populations of the beetles are down significantly and it is safe for us to plant species again like cranberry bush and arrowwood viburnums. They’ll get a little bit of damage but nothing lethal.

"Why did the populations go down? It seems with all the very susceptible native plants that were around initially allowed the populations to reach unnaturally high levels and the beetles moved into landscapes annually. With those food sources gone the populations declined. Also, and maybe more importantly, predator insects, and nematodes that affect the larva in the soil have built up and found the Viburnum leaf beetle as a food source!

Nature Walk in Herrontown Woods, Saturday May 4 with John L Clark

Update #2: Great walk, with showy orchids in full bloom. A writeup is on the FOHW.org website. 

Update: The walk will take place as planned. Predicted rain has not materialized.

The Friends of Herrontown Woods will host a nature walk Saturday, May 4 at 9am, co-led by John L. Clark and myself. John is a botanist specializing in the flora of Ecuador. He was an associate professor of botany at the University of Alabama, but family logistics lured him to Princeton, where he joined the faculty of the Lawrenceville School in a long-titled position, the Aldo Leopold Distinguished Teaching Chair. John's also an avid birder, so feel encouraged to bring your binoculars.

Though we've been installing dozens of stepping stones to traverse muddy patches of trail, please wear appropriate shoes.

Meet at the main parking lot, off of Snowden Avenue, across from Smoyer Park. This link takes you to relevant maps.

Some wildflowers recently seen in Herrontown Woods:

Jack in the Pulpit

Spring Beauty

Mayapple--it's flowers are hidden beneath the leaves.

A profusion of skunk cabbage along a stream. When I lived in North Carolina, another species that lined streams and greened up early in the spring, painted buckeye, was reportedly used long ago by pilots to navigate before the trees leafed out.

Trout lily, which was blooming earlier in the spring.