Green Roof in Atlantic City

This "green roof" has been growing, or at least persisting, on top of the Atlantic County Utilities Authority for a number of years now. Funny thing is that the portions of it that are green--those blotches of white clover on the right--are actually considered a weed in this context, and should be taken out.

The brown areas consist of several kinds of sedums that despite their appearance are alive.

You'd think that a legume like white clover, which fixes nitrogen from the air and thus makes the soil more fertile, would be a good thing. But in fact there is a reason to keep the soil poor. A more fertile soil will encourage more weedy growth, which in turn will shade out the sedums and leave nothing but weeds. If a drought comes along, and  the weeds die out, the roof will have lost its vegetated cover. Low-fertility is actually beneficial in this situation, and likely has a lot to do with this roof being less weedy than others I've seen. Another reason to limit nutrients is that any runoff not absorbed by the roof will head into the local waterways through the storm drain system.

Rick Dovey, our tour guide (the tour was organized by Sustainable New Jersey), told us that the green roof has markedly reduced heating and cooling costs for the building.

Here are some sedums planted in what is essentially a miniature green roof, on the Mall near the Botanical Gardens in Washington, D.C.

Wawa Grows a Prairie

Wawhat's the Wawa growing? A bit shaggy for a butch cut. The proof is in the roof. Clearly, the Wawa at the Dinky station has gone green, or tawny, depending on the season. Take the building out of the picture, and you have a prairie out in big sky country. For a botanist, the question is not how all those prairie grasses got there--Princeton University has been designing green roofs into, or onto, a number of buildings in recent years--but whether the grass is little bluestem or broomsedge. Time to pull out the ladder for closer inspection. A vegetated roof reduces stormwater runoff from the building, and also provides insulation.

Another aspect of the Dinky Station's landscaping: Most of the trees are Kentucky coffee trees and a thornless version of honey locust. Both of these species tend to leaf out late in spring and drop their leaves early in the fall. Both are relatively rare in local woodlands, in part because their seedpods were in the deep past eaten and spread mostly by America's now-extinct megafauna. They make great landscape trees, though, because they leaf out late in spring and drop their leaves early in the fall. That means they shade the pavement and buildings only during the warmest months, then generously allow the sunlight's warmth to reach the ground during fall, winter and spring. Some research might show that the trees' internal clocks and large seedpods evolved in an ice-age world of short summers and big animals with fur the length of the Wawa's roof.

The bark of the Kentucky coffee tree has a characteristic chipped appearance,

in contrast to the smooth bark of the honey locusts.

Here's a grove of honey locusts letting October sunlight reach the south-facing windows of the Dinky Station.



Found a past post about Dinky wildlife, and a post in which the vibrations of the Dinky's approach makes the trees dream of megafauna past.

The Many Blooms of June

There's a wooden heron that looks out on our backyard garden. I hope it's happy with its bay window habitat of orchids, christmas cactus and aloe vera, and pleased with all our efforts to steer the sun- and rain-drenched plant growth beyond the window pane.

The garden is a collection of mostly natives with a few non-natives mixed in. A garden and a mind are enriched, one by the other. A plant often has to first make it into the mind before it can find it's way into the garden, and the garden can surprise the mind with what pops up. Over time, both the garden and mind gain in variety.

It's been a particularly good year for the Virginia sweetspire, which along with its sweet spires has the added bonus of creating suckers near its base that can be dug and moved to new spots.

Elderberry makes up in berries and blooms what it lacks in grace. Maybe this year, being less distracted, and if the covetous catbirds cut us some slack, we'll set about harvesting the berries and making those delicious pies remembered from youth.

Most azaleas people see are evergreen and not native, but there are some wonderful deciduous native azaleas like this swamp azalea. Pinxter azaleas were once common in Princeton woodlands.

More subtle is the native Euonymus that are mostly browsed down to a few inches high in local woodlands by the deer. Their ornament comes later in the year, with the bright berries that give them the name Hearts-a-bustin. These I found locally, grew to size, and have begun placing in the "botanical garden" at Herrontown Woods, protected by cages. Otherwise they would be eaten down and never flower or make berries.

Even more subtle is winterberry--a holly that's growing in one of our miniponds. Our front and back gardens get a boost from runoff from the roof and the neighbor's yard, all directed into many shallow depressions where the water can collect and seep into the ground. Managed well, the puddles can serve as mosquito traps, luring female mosquitoes to lay their eggs, then drying out before the larvae can mature.

Sundrop flowers surround the leaves of richweed.

Fringed loosestrife seems a delicate and bashful native, with flowers pointed down, but has been a surprisingly aggressive spreader when placed in the protected, fertile environs of a garden. It may need to be planted in a shadier spot where it won't have so much energy to expand.

Beardtongue (Penstemon) blooming in a garden means it's also blooming out in the wild.

The deeper depressions we have in the backyard swale are populated by all sorts of plants that thrive in wet, sunny spots. This is royal fern, which stays in place, while sensitive fern tends to spread.

Many kinds of sedges provide a nice background texture. This one is fox sedge, which is less ornamental than fringed sedge and bladder sedge.

A personal favorite is soft rush, whose green "blooms" arise partway up the darker green leaf stems, like elaborate earrings. It's stems may be soft but it's a tough plant that can be found growing in ditches. Bring it into the garden and it achieves a graceful vase-like shape that makes for an accent that's both striking and subtle.

Botany teaches us to make distinctions, for instance between sedges and rushes--which look like grasses but aren't--and the many attractive plants that actually are grasses, like this deertongue grass, here shown next to a rising sea of jewelweed.

Fragrant Japanese honeysuckle always finds a way to survive our periodic attempts to discourage its rampancy.

Across the street, unfettered Japanese honeysuckle is overwhelming a hedge. Eventually, the hedge will die from all the competition, and the honeysuckle vine will play king of the slowly collapsing mountain as the suffocated shrub rots and buckles from the weight. Passerby will still think it's a hedge.

Coral honeysuckle--the native honeysuckle vine--grows along Nassau Street.

Meanwhile, back in the backyard, bottlebrush buckeyes are working on some spires,

and the oak-leaved hydrangias are getting ready to put on a show.

During a pandemic, it feels like such wealth to have nature close by, thriving through it all.

Monarchs Bring Dance, Delight and Larger Meanings to a Backyard

These are the glory days for monarch watching, with the backyard packed with flowers--a veritable feast that we are grateful to provide.

Lovely as it is, the levitated landscape of pinks and yellows, reds and whites, gains a deeper meaning when a monarch arrives to animate the garden with its fanciful, danciful flight. Brilliance of color is matched by brilliance of movement, with glides and hairpin turns, sudden dips or dartings upward, gracing a garden's contours as if its flight were a form of affection. With an uncanny mix of power and whimsy, the monarch looks to know what it's looking for, as it approaches then darts away or doubles back, each minute of its flight a hundred instant decisions. What makes it land on one flower after approaching and rejecting so many others, seemingly the same, is a mystery.

This morning we saw four at once, two of which flew together, then collapsed upon the carport roof, there to mate for a minute while I ran to grab my camera. The one in front looks to be the female, with thicker veins and no little black spot on the wing.

This one here is a male, judging from the less prominent veins,

and those little black spots on either side of its abdomen.

The monarchs were especially drawn to the joe-pye-weed that with the summer's heat and rain have grown to ten feet high, like a mountain range of flowers.

Sometimes, when a monarch flew and flew around the garden, looking, looking, I thought it might be searching not for nectar but for a milkweed plant to lay its eggs on. Our swamp milkweed disappeared some years back, and this year my wife bought this kind, with orange and yellow flowers. Turns out to be tropical milkweed, native to Mexico but not here. It's pretty, easy for nurseries to grow, and rebounds quickly if ravenous monarch larva consume its leaves. It's also said to have some aspects, given the nature of its more tropical growth, that would make our northern native species of milkweed a better option,

like this butterflyweed that is flourishing in a neighbor's garden.

Most of Princeton's milkweed is common milkweed, which is less ornamental, spreads underground, and can be found in fields, along roadsides, and in this case growing at the nearby Princeton High School ecolab wetland. Other species include purple milkweed, a few of which grow at Herrontown Woods, and green milkweed, found years back in the meadows at Tusculum.

The dominant ideology of our day has deprived us of the satisfaction of contributing to something beyond ourselves. I grow more garden and less lawn because I love native plants, but the monarchs connect the garden to something much larger. Each March, starting out from their wintering home on just a few acres in the mountain forests of Mexico, the monarchs stretch themselves across all of eastern North America, ambassadors of beauty, as if to tell us that all our small efforts, spread across the land, are additive in and to nature, that we can contribute to something profound. May the monarch teach us how to find that satisfaction in other aspects of our lives as well.

Nature's Upside Down Pecking Order

On June 19, the Princeton High School ecolab wetland was one of the stops on the Green Building and Garden Tour, organized by the Princeton Environmental Commission. The intention of this tour stop was to focus on how a retention basin can be converted into wetland habitat, but an airborne drama pulled our attention skywards.

A red-tailed hawk flew over from Westminster campus, chased by a pack of crows.

The scolding and intimidation continued for several minutes, as the crows took turns dive-bombing the hawk. The hawk kept an eye out, but seemed generally unconcerned. They'd all been through this before.

After the crows left, the hawk lay down and draped its wing over the edge of the roof, as if injured, or simply wishing to gather some warmth from the sun.

The crows returned, the hawk flew off, but one of the crows hung around long enough to in turn become the target of intimidation by a still smaller bird with white markings on it tail.

During summer break, it's feistiness rather than size that makes for a schoolyard bully.

Redbud Leaffolders and Orchids--Herrontown Woods in July

While the woods seems to slumber, July brings another wave of flowers at the Herrontown Woods botanical garden and the Veblen House grounds. Whether the number of flowers constitutes a wave or a ripple, the photography that is standing in lieu of an actual nature walk during COVID times captures something of the feel of walking the pathways.

I have seldom seen Culvers Root growing in the wild, but it is a native with a beautiful form to its flowers. You can see the flowers beginning to open at the bottom of a spike, commencing a slow progression upward that serves the pollinators well.

The mountain mint donated to us is thriving, its strong minty flavor protecting it from the deer.

Shrubby St. Johns Wort blooms for a long stretch in the summer, living up to its latin name, Hypericum prolificum. The deer leave it alone as well.

We human deer are letting a few pokeweeds grow to maturity. It has an annual stem growing from a perennial root, and can become too numerous if left unchecked. A previous post mentions the intentional or unintentional use of its berries as a dye, and an interesting tree-like relative it has down in Argentina, called the ombu.

Not sure what this soporific bumble bee was doing on a velvety leaf of wooly mullein, a dramatic nonnative weed I associate with rail lines in the midwest, but which shows up here and there in Princeton.

The drought prompted the installation of a gutter and cistern next to the roof of the kiosk at the Herrontown Woods parking lot. One rain keeps us in water for weeks, as we walk around the gardens, giving new plantings a much needed drink.

Insects have been taking advantage of the many kinds of native plants we're growing--more than 100 species thus far. Meadow rue, for instance, is a seldom encountered wildflower in Princeton, discouraged by shade and the appetites of deer. But in the botanical garden, we can grow it in a protected, sunny setting. On May 10th this year, one of the tall meadow rues was found "donating" its foliage to caterpillars of the Meadow Rue Owlet moth, Calyptra canadensis. Thus a protected setting for seldom seen plants provides habitat for specialized insect species that otherwise have slim pickings in Princeton.

Another giving was discovered a couple days ago, on a redbud tree, some of whose leaves were folded up and turning brown.

Strands of silk tether the leaves, making protective chambers within the wrappings.

Opening one up, like a clamshell, reveals some energetic caterpillars busy chowing down and leaving dark trails of frass in their wake.

The speedy caterpillars are larvae of the leaf folder moth, with the provocative latin name Fascista cercerisella. Readers will be relieved to know that the insect is not a fascist. Originally, the word meant "bundle", as in a bundle of sticks, which can be extended to bundles of people who are part of a political movement. A fascicle means a bundle of leaves or flowers, while the Fascista caterpillar bundles itself up in a folded over leaf. The "cerce" in cercerisella likely comes from the insect's preference for laying its eggs on redbud trees, Cercis canadensis.

Up the trail at Veblen House, a patch of wineberries is going uneaten. As we've been clearing the invasive growth on the Veblen House grounds, a neighbor lamented that we had removed her favorite patch of wineberries, whose fruit are one of the small rewards for those who persevere through the muggy heat of a Princeton summer. Responding to neighborhood input, we've kept a few patches of wineberries.

Few will notice that the green fringed orchids at Veblen House are in full bloom. We've caged some to protect them from the deer. Below is an enchanting closeup of the flowers, giving the impression of wood sprites.