Weeding Princeton's Fuel Tank Raingarden

When neighbor's complained about the appearance of the fuel tank on Witherspoon Street, the town responded by removing the fueling station's roof, adding a brick facade, and planting the raingarden that had been built to catch and filter runoff from the pavement. 

With the raingarden looking good in its first full year, the intended plants tidily mulched and flourishing, you'd think that it's time to sit back and enjoy nature's beneficence.

But as a gardener who has seen many a raingarden succumb to weeds, I could not help but notice the first signs that a silent, weedy insurrection was in the works. Here is a small patch of mugwort, planning a rhizomatous takeover.

Here's another little, harmless-looking cluster of mugwort next to a lovely St Johnswort shrub. And what's that grasslike plant in the background? That would be nutsedge, easy to pull but also with an underground network of roots that is hard to exhaust. If allowed to grow, it too will spread everywhere. 

The weeds look harmless when there are just a few, but a gardener can extrapolate in the imagination from a little to a lot. I couldn't help myself, and intervened. How many gardens are at such an early stage when thirty minutes of weeding can nip invasion in the bud? Here are horse nettle, mugwort and nutsedge. Feel for the triangular stem on the nutsedge. "Sedges have edges."

Here is white clover, which is benign in a lawn but muddles things in a flower bed.

On the left is a vetch, not crown vetch thankfully, but still worth pulling. 

I pulled pretty much every weed except the nutsedge, whose takeover will hopefully be forestalled by the designated caretaker, if any. Afterwards, the raingarden looked to most eyes exactly like it had a half hour prior. The reward of proactive action is in imagining all the future work that has just been avoided. There will be more work, surely, but much less. 

Maybe someone with designated responsibility would have done the weeding anyway. Nice to think but hard to count on. 

Meanwhile, on the other side of the new fire station, another raingarden was planted at some point. Lots of good stuff growing, but much more intimidating in terms of weeds. It shows what happens when the weeds are allowed to gain a foothold.

The pink is crown vetch, an aggressive plant originally introduced to the U.S. to control roadside erosion. 

And then there's birdsfoot trefoil, originally introduced to the U.S. as nutritious forage for cattle.

And relentless bindweed growing up and over the native swamp milkweed. 

Subduing these three tough customers would take some major work, which makes it all the more amazing to be able to weed the other raingarden and feel like one has the upper hand. 

All of this leads to a point, or two, made before, that regulations require the planting of raingardens in the name of reduced flooding and increased water quality, yet maintenance operations are set up to handle only the simplest of landscapes--turf and trees. Raingardens are a complex community of plants, not a monoculture. They don't respond well to "mow, blow, and go." The person who cares for them needs to be more physician than custodian. They can be planted by people who don't really know the plants, but they need to be cared for by people who do, in a culture that devalues informed maintenance. 

Princeton Finally Plants its Fuel Tank Raingarden

The raingarden in front of the municipality's fuel tank on Witherspoon Street finally got planted. Like just about every piece of real estate in Princeton, large or small, this raingarden has a long and turbulent history. It was presumably created to receive runoff from a roof the town had built over the fuel tank. The roof was meant to protect staff from rain while they poured fossil fuel in their gas tanks, but spurred passionate complaints from neighbors, who complained about the visual blight upon a main entryway into town. 

Thus began a long period of deliberation and rethinking, leading to the removal of the much-maligned roof, and consideration of whether to spend even more money to move the raingarden somewhere else, for whatever reason.

While humans hemmed and hawed, nature began populating the bare dirt with various weeds, leading to a post on this blog called Princeton's Fuel Tank Raingarden Wannabe, identifying the various weeds and discussing which would be worth keeping. If one knows and loves plants--knowing and loving being very much intertwined--it's pretty easy to develop a new raingarden planting simply by editing what pops up on its own, augmented by taking excess plants from an existing raingarden and planting them in another. Planting one raingarden makes the next one all the easier to create at no cost beyond time spent.

The town has its own logic, however, for better or worse. The raingarden was left untended for a couple years until the brick facade disguising the fuel tank was completed, and then in mid-October a host of plants were purchased and installed, along with a thick layer of mulch. 

Soft rush were densely planted at the lower end, with purple coneflowers and black-eyed susans on the slopes. 

Though the men may not have been overjoyed at the task, it was good to see public works employees working with hand tools, away from all the rumbling machines that burn the fossil fuels hidden behind this raingarden. 

Beyond the benefits of raingardens--filtration of runoff, groundwater recharge, food for insects and birds--they are above all a quiet space. Raucous lawn mowers and leaf blowers are of no use in a raingarden, where only quiet tasks like weeding and planting are needed. 

The relentless racket of custodial lawncare that people so resent in our neighborhoods is the sound of machines simplifying and dominating nature while they feed climate change. When was the last time you saw an employee, public or private, quietly using hand tools in a garden? That's what made this scene along Witherspoon Street special. 

Nature's "Depressions" Bring Beauty and Resilience

Another in my writings about the ecological, logistical, and psychological aspects of tending to a detention basin at Smoyer Park that we converted into a native meadow. Most of the photos and writing are from mid-July, 2021.

There's a garden that many people pass by but few notice. I saw my second monarch butterfly of the season there in mid-July, attracted to the subtle flowering going on there. It's at the far end of the parking lot in Smoyer Park, out Snowden Lane. Drive or bike down to the lower end of the lot, and by heading downhill, you're essentially following the water, doing what rain does after it hits the ground. And there you will find what most people, if they have any name for it at all, will call a detention basin, so-called because it detains runoff, slowing it down, capturing it in a depression so that it can seep into the ground and feed the aquifer rather than feed a flood.

Bureaucracies require it, engineers designed it, but probably none of them were thinking about what a great place this wet, sunny spot would be to grow native plants. That came later, when another arm of the government, Partners for Fish and Wildlife, worked with me and the town to turn this previously mowed space into what could more aptly be called a wild garden, or a wetland garden, or a wet meadow. 

"Depression" is a word that in psychology may have a negative connotation, and extended depression is surely something one would want to cure. But if you're an artist of some sort, a depression may mean the mind is doing important work at a very deep level, putting things together in a new way that may lead to a burst of creativity, insight, or both. To experience highs, one must be able to experience lows. 

Nature, too, needs its lows, even though depressions in the ground, too, tend to get a bad rap. "Drain the swamp" is a politician's stirring call to clean up the mess inside the beltway, and lots of swamps were drained when they got in the way of expanding our towns, cities, and farms. But as with people, a depression is where nature does some of its deepest thinking and finest work, feeding the aquifer and laying the foundation for foodchains with a rich variety of native plants. Gardeners like to lift plants up in raised beds, but many native wildflowers prefer the opposite, somewhere low down. Those are the seedheads of big bluestem in the photo, a dominant prairie grass in tallgrass prairies of the midwest, historically munched on by bison. 

You can see a fence bordering one of the ballfields at Smoyer Park in the distance, and most of the surprisingly many detention basins scattered across the Princeton landscape, in developments or at parks, are managed like a ballfield, with grass mowed to the ground, though no one would think to play a game there. One thing I've managed to do in town is get some of these converted to wet meadows--first at Farmview Fields, then at Princeton High School, then at Greenway Meadows and Smoyer Park. 

I walked through the Smoyer Park wet meadow in mid-July, to see how it's doing and to do some weeding of this half-acre wild garden. As any gardener knows, there's a lot that can go wrong, even in a meadow that's supposed to grow naturally. Many of these raingarden-like plantings, if untended, fill with a host of aggressive weeds, like mugwort, Canada thistle, and Chinese bushclover (also called Sericea lespedeza). Even natives like blackberry and some kinds of goldenrods can tend to take over.

Nature is complex, which can be daunting and even off-putting, or exciting for those who take an interest and build familiarity one plant at a time. That's where love comes in, because when you love something, you want to know everything about it. Botanists talk about plants like a baseball fan might take pleasure in quoting obscure statistics or reminiscing about certain players. Love turns complexity into joy. Love is also what gets one out there to check up on a wild garden, to make sure it's doing okay.

Knowing how much can go wrong can increase the pleasure at seeing so much going right. Now, this photo shows little in the way of blooms, but a gardener conversant with the species of a wild meadow can experience joy even before plants flower, is moved as much by what will be as what already is. Each stem of a favorite wildflower implies a bud, each bud a flower, and each flower a host of insects that in turn support a foodchain of wild life. 

A botanist gardener can see in this photo the spray of monkeyflowers in the lower left, the burst of rose mallow hibiscus in the center right, and behind them a favorite sedge called woolgrass rising towards maturity. Other species, too, are gaining in number and moving towards bloom--ironweed, partridge pea, blue vervain. From evidence of browsed stems, even the deer's appetites seem in balance, leaving many plants to grow unhindered. The diverse mix of sizes and textures triggers memories of other rich meadows seen--prairies in Ann Arbor, MI, Durham, NC, Chicago. How many people get to travel back in time and across half a continent, just by weeding a detention basin in a park in Princeton? 

Occasionally, a less sanguine thought can intrude. What difference does it make that a half acre meadow is prospering, when a whole planet is so quickly being overheated? Delight in mid-July could not completely eclipse news heard earlier that day, of environmental and cultural devastation in Europe, as an overheated atmosphere unleashed a flood that shattered all records. 

September 12, 2021

Since mid-July, Princeton had its own megaflood when Hurricane Ida swept through the night of Sept. 1. Basements flooded that had never flooded before. The DR Canal towpath was badly damaged, ten years after being similarly damaged by Hurricane Irene, and only two years after being fitted with a fresh cinder surface for walking, biking, and jogging. 

But one place I didn't worry about getting flooded was the detention basin at Smoyer Park. It's built for flooding, and fitted with native plants that have evolved to thrive on periodic floods. Though, being the caretaker, I will be worrying about whether I could be doing more to limit the spread of stiltgrass, carpgrass, canada thistle, blackberry, and various other overly aggressive species, to a passerby the meadow has a late-summer look of subtle earth tone radiance and balance. The white in the distance is late-flowering thoroughwort, mixing with the emerging yellows of goldenrod, a few lingering spikes of purple from the ironweed, and the bronze of tallgrass prairie species--big bluestem and Indian grass. 

Last year's post about Smoyer Park's basin: The Work Behind a Natural-Looking Meadow

A Rather Long Snow Storm

Here in Princeton, we have artisanal snow removal services, as in this thoughtfully crafted mohawk for the Prius.

Good news about the frontyard raingarden: it works great as a snow garden as well.

During this extended, ground-breaking, or at least ground-exposing, Snow Removal Initiative (SNI), it was important to take frequent breaks to document the innovative "shoveling" technique being used. The Royal We Committee believes this approach, if successful, could serve as a model for other homeowners to emulate. Later in the morning, we saw neighbors beginning to utilize this very method, suggesting our demonstration project could have a transformative impact on snow removal in Princeton and beyond. 

The Initiative included a research component. Careful study of this cross-section of the cliff face reveals the various strata laid down by the storm. This having been an unusually long snowstorm, it's understandable that the darker patch in the middle was at first mistakenly dated back to the early Devonian. Further analysis and some equipment tweaking showed that snow in the darker stratum likely fell during the warmer daylight hours the day before, with the lighter layers above and below having been deposited during the preceding and following nights.

Other keen observations: some of the neighbors didn't get the memo. Recycling postponed until Saturday, or the mid-Anthropocene, depending on how long the storm lasts.

What is snow good for? Enforced social distancing, for one. Not likely to have a close encounter with the neighbor for some time to come. And the kids can sort of remember what it used to feel like to get a snow day.

Other writings on excessive snow include an oldie but goodie: Snowbound Language

Fall is Burstin' Out All Over

After the heavy hitters of late summer are past--the Hibiscus, coneflowers, bonesets, et al--it's easy to think the season of native wildflowers is over, but this fall has been a surprise in the beauty and variety that nature held in reserve for these sweet autumn days. 

One that's been a big hit at Herrontown Woods is Hearts-a-bustin', though I prefer to call it Hearts-a-burstin', because when I see it my heart does more burstin' than bustin'. 

This native euonymus (E. americanus) would be a common shrub in the forest if not for the deer, who love to eat it, stem and all. They keep it browsed down to a couple inches high, so we had to take some of those and grow them out in cages so that visitors could see the ornamental seed capsules on the shrubs, one of which has risen to eight feet thus far. It helps, too, for the ornamental seed production, if it's growing in a clearing where the trees aren't hogging all the direct sunlight, like our Princeton Botanical Art Garden.

A little earlier in the fall when the capsules were just starting to open, you could see why it is also called strawberry bush. 

A solitary white snakeroot is growing near a Hearts-a-burstin' planted behind Veblen House. It can easily be confused with boneset and late-flowering thoroughwort. When I first moved to Princeton almost 20 years ago, white snakeroot was common in some areas, even weedy, being one of the few native wildflowers that deer didn't eat, but it seems much less common now. 

A few fall flowers in Herrontown Woods manage to bloom despite deep shade. Wood asters adorn some of the trails, 

occasionally accompanied by a wreath goldenrod.

More subtle is beechdrops, which parasitizes beech tree roots rather than producing its own nourishment through photosynthesis.

Along a busy street in a frontyard raingarden fed by runoff from the roof, blue mistflower blooms profusely for an extended period while staying low. 

New England aster also brings color to the garden late in the season.

The white of late-flowering thoroughwort makes a good foil for New England aster's rich color.

Another cloud of white late in the season comes from what I call frost aster. Because it can become too numerous, I would in the past make plans to enjoy the bloom, then cut it down and remove it before the seeds were released. But once it's bloomed, it quickly fades into the background of landscape and thought, foiling the best of intentions to control. 

Turtlehead grows quietly and unobtrusively during the summer, bending around other plants to attain its tall, skinny, awkward state of maturity. The blooms make for a top-heavy look, but this year were solidly ornamental.

Indian grass is particularly pretty when growing in a distinctive clump, rather than crowded in a field. Like many prairie grasses, it responds beautifully to the wind.

Bottlebrush grass is more of an understory grass, and unlike most native grasses it gets an early start in the spring. 

This one's called woolgrass, for its wooly appearance, but is actually a sedge, with edgy triangular stems. Unlike most native sedges that get an early start in the spring and move quickly to flower, woolgrass takes its time, gaining more height and slowly developing its inflorescence, which is ornamental at all stages, particularly when backlit. Though typically found growing on wet ground, it has been thriving through our wetter summers when planted upland as well, as here in the botanical garden at Herrontown Woods.

There are many species of native sunflower. They can make a big and very welcome show in the fall after other tall yellow wildflowers like cutleaf coneflower and cupplant have faded. A powerline right of way in the Sourlands preserve is one of the few places where they really show their stuff around here.

In North Carolina, they had names like "giant," "showy," "woodland," and a rare one called "Schweinitzii." I knew giant sunflower (Helianthus giganteus) from only one derelict patch growing along a roadside outside of town, and decided to do it and myself a favor by taking a tiny bit of the patch and planting it in my garden and in a sunny opening in a nature preserve I managed in town. As often happens, what seemed like a species on the brink in the wild turned out to be prolific and expansive in the garden. 

The sunflower in the photo, though, is sunchoke, a sunflower that has long carried the name Jerusalem artichoke. Each year, I think I'll eat its tubers, which I don't, even though they have an appealing nutty flavor when eaten raw, and can work well in a stirfry. And each spring, I attempt to pull out every last sprout, tired of its aggressive underground spread. Then in the fall, longing for summer blooms to continue, I am thankful to find that my eradication efforts have once again failed to completely stem the tide. 

These are some of the flowers that ease the transition from summer's glory to a palette of browns and grays. Let their colors, and the rich spectrum of autumn leaves, penetrate deep into your soul, to carry you through the winter to come.

Princeton's Fuel Tank Raingarden Wannabe

Why would a plant lover be drawn to this desolate scene of concrete and asphalt? Because there's a raingarden behind that fence, or at least a raingarden wannabe, and that means I'm seeing not what is, which is pretty drab, but what could be, which is a dynamic, jubilant planting of native wildflowers, grasses and shrubs filling that skinny raingarden squeezed between the sidewalk and the town's fuel tank. The fuel tank was for awhile serving double duty, fueling town vehicles while its appearance fueled controversy in the neighborhood. A fine rain garden planting could go a long way towards healing the discontent, in my humble, totally plant-biased opinion.

The first good news is that the fresh layer of asphalt there appears to be appropriately tilted to shed its runoff towards the raingarden. What is a raingarden, after all, if the rain that falls on the surrounding topography doesn't flow towards it?

For some reason the raingarden hasn't been planted yet, so the plants have gone ahead and started planting themselves. It's looking a little sparse thus far. Or you could say that the plants are social distancing.

Whenever I see plants trying to colonize bare dirt, I think of people who live in an emotionally impoverished situation. Back when I was in that predicament, I was drawn to places like this. Weeds trying to grow in parched ground were my friends and fellow travelers. Maybe that's why I can remember plant names when most people struggle, because the plants aren't just variations on green. They touch something deeper in me.

This late-flowering thoroughwort is a keeper--a native wildflower whose name is unlikely to flow smoothly from many tongues. It grows like a weed, and often in weedy places, like abandoned fields or roadsides, but can sometimes achieve great elegance of form when it becomes covered with plates of white flowers in late summer. It shows up early, but blooms late. Thus the name.

Here are the leaves of mugwort, which adds no color and spreads aggressively underground, taking over neglected raingardens over time. It's a force for monoculture and monotony that must be countered early and often.

Smaller scale weeds are clustered here, close to the ground, with dandelion on the lower right, a mock strawberry in the middle, and one 3-seeded mercury on the left. When I see one or two mock strawberries like this, I'm also seeing five years hence when it will have spread to coat the ground in an unattractive and inedible way. That increases the motivation to be proactive and pull it out now, before the task becomes overwhelming. This ability to imagine the future, learned in a garden, is directly translatable to global issues like climate change, where the job only becomes harder the longer one waits. 

Lots of homeowners puzzle over what to do with hundreds of oak seedlings in their yards, when everyone is telling them we need to plant more trees. Most tree species don't need help. They plant themselves, often in inconvenient places, like this raingarden.

Playing the editor, I'd say this nonnative red clover is a keeper as well, but pull the tall sweet clover at the other end of the raingarden. Sweet clover can be kind of pretty in a gangly way, but it is one of those midwestern and western weeds that appear to be expanding eastward, like teasel, Queen Anne's Lace, knapweed, and wooly mullein. Having lived in the midwest, I've seen how they can start to take over.

Leaping into the void in plants and action a couple months ago, I pushed some "live stakes" of buttonbush into the bottom of the raingarden. Despite the poor, hardened soil, they have sprouted. Here again, I'm seeing not so much the less than impressive seedling but instead the 8 foot high shrub it could become if it's allowed to get well established.

Just up Witherspoon Street, at the Princeton Recreation Dept. headquarters next to the community pool, is a demonstration of how gardens can look if there's someone knowledgeable taking care of them year after year. There's some serious tending going on here. Even the scarily aggressive variegated goutweed (whitish leaves on the left), which tends to take over gardens, is neatly contained in a discreet clump. These gardens owe their existence and beauty

to Vikki, whose job description in the Recreation Department probably has nothing to do with plants. From what I've seen over the years, it's clear that Vikki is one of the few people in town who is hard-wired to have a soft spot for public gardening, like Polly Burlingham with her hanging baskets downtown, and the various school gardeners, and like Dorothy Mullen was until she left our world earlier this year. I'd say that all it takes is love, and from that all things follow--vision, knowledge, persistence, strategic timing.

Maybe the sad, forsaken raingarden wannabe just a block away will somehow become loved ground. It's got "good bones"--sun, inputs of moisture. Good things could happen.

The Thinking (and Action) Behind a Successful Raingarden

In this post, we explore the thinking behind a successful raingarden. Thought has power, in that it sometimes turns into action, and so we will explore the thought behind the action that has made this large native planting thus far succeed.

In this case, it is a detention basin in Smoyer Park that was converted from turf grass into a wet meadow dominated by native prairie grasses with some wildflowers mixed in. Planted by Partners for Fish and Wildlife, this large-scale raingarden appeared sparse its first couple years, but has now grown thick and subtly colorful with time and attention.

Thick, that is, with intended plants, which is not a given when a raingarden is planted. How many gardens of all sorts, no matter how lovely the vision that brought them into being, have been taken over by mugwort, Canada thistle, and other invasive weeds? Having been this raingarden's volunteer caretaker for its first three seasons, as part of my work for Friends of Herrontown Woods, I visited it recently to see what needed to be weeded, and found nearly nothing requiring my attention. For a gardener, this state of affairs is almost unimaginable.

How could this be? Well, it helps to have planted a strong backbone of tall native grasses:

Indian grass

and big bluestem, to claim the space.

The caretaker's job then becomes a matter of influencing what other species come up in the spaces unclaimed by the grasses. Given limited time, a caretaker must learn to recognize each species and know from experience what to weed out and what to leave. Balance, beauty, and diversity are the goals. Some weeds like mugwort, Canada thistle, and crown vetch are notorious for taking over, and so were weeded out early in the game, before they could become too numerous and ruin any chance for diversity and beauty.

Others, like this fluffy-seeded, native but weedy pilewort that is growing lustily around the edge of the meadow, are judgement calls. I left it in, hoping it will behave like lambsquarters--another annual that makes a powerful showing one year but largely disappears the next.

(An example in this raingarden of a species that was numerous one year, gone the next, is black-eyed susan, which was in the original seed mix and generated lots of color before disappearing this year.)

There are a few native perennial wildflowers that have moved in on their own. At this stage, they are relatively few, and add spots of color and late-season nectar. But I don't entirely trust that they will continue to "play well with others." These include late-flowering thoroughwort,

a goldenrod species with narrow leaves,

and frost aster.

Providing bright color earlier in the season was one large specimen of false sunflower (Helianthus helianthoides)--commonly found in seed mixes for wet meadows. In another raingarden some years back I found it to be overly aggressive, but how it will behave here is yet to be seen.

A native annual I wish would spread around more is jewelweed, whose tubular orange flowers serve hummingbirds all summer long, and whose explosive seedpods delight anyone who takes one in their palm and touches it. Usually, the plant is rambunctious enough to survive the insistent browsing of deer, but for now it's huddling against the concrete outlet, chewed down before it can flower.

A "seed bombing" conducted by a girl scout troop in late spring may have been the origin of these young rose-mallow hibiscus (Hibiscus moscheutos),

and some ironweeds. These are local wildflowers we added to get more color and cater to the pollinators. Both of these can get tall, but may end up being kept low by deer browsing.

One of the pleasures in this wet meadow thus far, surely unnoticed by passersby and hard to photograph, is the clarity, by which I mean one can see inbetween plants all the way to the ground. Low-growing weeds like stiltgrass, carpgrass, ground ivy, and many others tend to muddle the planting, obscuring the ground. This clogged condition, the visual equivalent of listening to a scratchy record, has ecological as well as visual impacts. If the spaces between the bunch grasses are clogged with weeds, ground feeding birds have a harder time navigating, and can become more susceptible to disease from rubbing up against wet foliage.

An encounter with a garden that needs no weeding brings, for an experienced gardener, a mixture of feelings. There's surprise, some quiet pride and elation (that past interventions could have had such a positive effect), and a sense of foreboding. Surely I was missing something.

As it turned out, there was good reason for the foreboding. Getting ready to leave, I spotted a small patch of stiltgrass invading along one edge. Unlike lambsquarters or blackeyed susan, which can be prominent one year, gone the next, stiltgrass is one of the uber-invasives, an annual that grows ever more numerous with time, producing billions of seeds each year. Inedible to wildlife, it creates a stifling appearance, making a planting or whole woodland appear to be blanketed with green cobwebs.

Since its seeds were not yet ripe, I pulled as much as I could find out of the ground, then collected them all and threw them in a nearby woods where stiltgrass had already invaded. The source of the stiltgrass was actually the mowed lawn that surrounds our wet meadow. Given that stiltgrass can grow and seed even though only a few inches tall, the lawn is likely to remain a source of invasion for the foreseeable future. Since the weed prefers moist conditions, the more frequent and heavier rains we are experiencing due to global warming will only make it more aggressive. There continues to be hope that something--a fungus, an insect--will figure out how to consume it and thereby begin to bring stiltgrass into ecological balance, but that wait could be long.

These, then, are the thoughts that fill a wild gardener's mind when visiting a raingarden. Because the aggressive weeds were caught early--nipped in the bud, so to speak--the visits need only come once or twice a month for an hour, even for a wet meadow nearly an acre in size. Knowledge and experience make for strategic, efficient interventions. There's time left over to appreciate the bright flowers of partridge pea and the growing diversity. And it's satisfying to know that in a landscape dedicated to ballfields, a lowly bumblebee or the occasional monarch butterfly will still find some sustaining habitat when visiting Smoyer Park.