A Special Bluff With Special Flora

There are places in nature that feel special in some way, places we find ourselves returning to. One special place for me is a bluff in the lower valley of Ellerbe Creek--a stream in Durham, NC for which I founded a watershed association a quarter century ago. 

During a recent visit, I took a walk with naturalist Cynthie Kulstad in one of the preserves we created back then, 80 acres called Glennstone Preserve. Cynthie is the botanist/horticulturist who helped sustain many of the plantings I had nurtured in parks and nature preserves while living there. The trails and our inclinations led us down to this special spot, on adjoining Army Corps of Engineers land.

Crowned by a massive white oak, the bluff is a collection of diabase boulders and uncommon plants overlooking the creek. 

One of those uncommon plants that makes this spot distinctive is resurrection fern (Pleopeltis polypodioides), all curled up and dried out on one of the boulders. Resurrection fern is an epiphyte, meaning it builds itself largely out of water and air, pluse whatever few nutrients collect on the rock it clings to from fallen leaves. Unlike most plants, this fern's leaves can dry out during droughts, then rapidly rehydrate after rains.

The only other place I've seen resurrection fern in Durham is on a similar but much larger bluff, where the Eno River just to the north encounters a mass of diabase rock and takes a sharp turn to the right, called Penny's Bend. I sense a kinship between these two bluffs, botanically and geologically. They could be called Big Bluff and Little Bluff, reflecting the respective size of the watersheds they are in.

(Up here in Princeton, NJ, with the same piedmont geology as Durham, a similar relationship can be seen between the big "Roaring Rocks" boulder field in the Sourlands and the boulder field in Princeton's Herrontown Woods, where the boulders are smaller and the water tends to chuckle and murmur rather than roar. These geologic features, too, are composed of diabase rock that resisted erosion through 200 million years.)

Looking up, I spotted another unusual native plant, eastern mistletoe (Phoradendron leucarpum), growing high on a tree branch. This one's a hemiparasite, meaning it extracts some sustenance from the tree but also has green leaves to make some of its own energy.

Other trees nearby also had dense balls of vegetation high up in the branches, but they weren't mistletoe. Those are witch's broom--a dense cluster of twiggy growth that is the tree's response to a pathogen or other irritant. Cynthie pointed out they are common on hop-hornbeam, a tree I hadn't seen in a long time and had been wanting to run into.

Turned out we were in the midst of a grove of eastern hop-hornbeam (Ostrya virginiana), growing along the edge of the bluff. (Upon returning to Princeton, I found some of these with their distinctive bark growing in Autumn Hill Reservation.)

Another tree nearby, judging from the leaves on the ground, was swamp chestnut oak (Quercus michauii). Paul Manos of Duke University calls these "sun leaves," meaning they are leaves that had been growing higher in the canopy and thus received a bigger dose of sunlight. They're smaller, thicker, and with sharper lobing than the more shaded leaves below.

I found more online about sun leaves and shade leaves, in a post by Gabriel Hemery:

"If there is some sunlight however, even a little diffuse light (see below), then a tree makes the most of it by producing shade leaves lower down in its canopy. Shade leaves are larger and thinner than normal sun leaves, and often appear a darker green (they contain more chlorophyll). They also have half as many stomata than sun leaves, or even fewer, and so have a lower respiration rate. They can react quickly to brief bursts of sunlight and dappled shade.

Shade leaves can turn into sun leaves and visa versa; providing that the change is gradual. This is something that a gardener moving a plant outside that has been grown indoors or in the greenhouse, must be aware of. When a plant is taken outdoors, place it first under shade and gradually over several days increase its exposure to bright sunlight." 

It would be interesting to know if pine needles, like those high up on this shortleaf pine, also vary according to how much sun they receive. 

During my eight years in Durham, plus many return visits over the years, I've found many special places along Ellerbe Creek. They could be as simple as a native azalea leaning out over the creek, or as complex and improbable as a roadside embankment packed with more than 100 native species of piedmont prairie. A few have been tragically destroyed, but it's heartening to return to those that persist, their charms sustained, their uniqueness unshattered by a rapidly changing world. These pockets of stability give my soul something to lean on.

Proliferating Paradise

If you asked me what a utopian landscape might look like, it would be something like this. People talk more of dystopia than utopia these days, but this enclave stirred memories of utopian dreamers who were more common a half century ago. This is not a utopia filled with fantastical gizmology, but a more basic collecting of solar energy by plants and people to fill our needs for comfort, food and beauty. Though a deep forest would be somewhere nearby, houses would be producers, not just consumers, their roofs shaded by solar panels sending renewable electrons out into the neighborhood grid. And their front yards would be producers as well, of a joyous mix of wildflowers and vegetables.

Wild plants would mingle with domestic, and people would be a gentle mix of wild and domesticated natures as well. On this particular day, a neighbor was harvesting cucumbers and tomatoes while we plant lovers were inspecting the leaves of a curious plant grown from seeds we had collected from a wild remnant on the outskirts of town. We continue to be stumped. It's some sort of Silphium, not quite cup plant, not quite rosinweed. Genius nature has taken our breath and turned its carbon into yet another surprise.

The garden is largely the work of my friend Perry in Durham, NC, who began gardening in his own yard, then extended his work into his grateful neighbor's. Other neighbors on the block have picked up on the theme, getting acquainted with plants one at a time, until their lawns too have been displaced by something much more interesting and productive. It's a miniature experiment in proliferating paradise.

Perhaps paradise is too strong a word, being associated more with leisure than production, more with a tropical beach and soft sea breezes than an urban front yard. This is a plant-based, pandemic-borne, home-centered paradise.

I'm in Durham partly to see a close friend, but also to work on my house there, a 1919 house surrounded by towering oaks, but with a big lawn drenched with sunlight and potential to grow all kinds of interesting things. Being a long-distance gardener is even more challenging than being a long-distance landlord, particularly during a pandemic, but last fall, we started by planting seeds of local wildflowers and grasses around stakes in a part of the lawn where the soil had been freed of Bermuda grass. Perry didn't get my hopes up, sending periodic reports this spring of copious amounts of chickweed and weedy cranesbill filling the void in the lawn. It was a great surprise then to finally show up and find an enthusiastic crowd of intended plants around each stake, enough to populate a much larger portion of the lawn.

This is an unorthodox way of proliferating prairie. I used a similar technique at the botanical garden at Herrontown Woods in Princeton, where toddlers and their moms planted wildflowers in staked pods like this--mini-nurseries of clustered plants that were transplanted the next year to begin filling the whole forest opening. As the transplants produce seeds, they expand the overall planting still further.

Perry's been using incrementalism in a Durham nature preserve as well. At 17 Acre Wood, the first urban preserve I helped create in Durham 20 years ago, Perry and I checked out the hazelnut crop in a floodplain he has been working to shift towards native species.

One of the toughest spots was clogged with climbing euonymus, english ivy and periwinkle. Trees tend to be native, the understory not, but Perry is shifting the balance. It's hard to grow much in deep shade where water stands for much of the winter, but where the invasives have been removed, elderberry and jewelweed have bounced back, and a patch of lizard's tail has appeared.

The work is partly ecological, partly aesthetic, partly public safety, since removing invasive shrubs and vines improves vistas and sightlines along a public trail. This West Ellerbe Creek Trail, which follows the creek through the preserve, is also a story of incrementalism. It was a big hit with neighbors when it was built by the city in 2001, but would not have been built at all if not for the small steps that preceded it. A county government grant had helped our nonprofit create a nature preserve along the creek. Then the city, seeing we had created a destination, built the creekside bikepath to reach it. The result was a way for neighbors to take a nature walk in their own urban neighborhood.

To shift the world towards paradise, we really don't need new ideas, only people and organizations and governments doing what they each do best, combining incremental action with caring about the world and what we'll pass to future generations.