Here's a nice surprise, I thought. I was leading a class through a young woodland at Duke Farms, reading the history of the forest by looking at the plants. We were surrounded by pin oaks and red cedars. Shrubs were scattered beneath the trees. A nearby deerberry was laden with sour fruit. And we were looking at a shrub with lustrous leaves, slightly toothed and aromatic.
I handed out a leaf for everyone to smell. It had highlights of citrus and a rich undertone of bay. As it should: this was bayberry (Morella pensylvanica*), a native shrub with a doubly apt name: it resembles the culinary bay in its aromatics, and it is often found near the shore -- the "bay", if you will.
While the "bay" in its name may be well-explained, "berry" requires a bit more imagination. The fruit is a small drupe with a single seed, covered in a gritty grey wax. The wax is utilized for its aromatic qualities and rendered into bayberry candles. It also is the source of an unusual wildlife partnership.
Rutgers professor Ted Stiles and colleague Allan Place studied the yellow-rumped warbler, a bird species that can readily be observed feeding on bayberry in late summer into winter. While most animal species find saturated long-chain fatty acids -- bayberry wax, for one -- to be fairly indigestible, they documented that these warblers readily digest it, with greater than 80% assimilation efficiency. Because this food is available primarily to yellow-rumped warblers, and bayberry fruit tends to persist into the winter, the warbler is able to overwinter well north of other warbler species.
Because of its low, tufted form and glossy leaves, bayberry makes a good landscaping shrub and a great hedge. We recently planted a few near our driveway, which Rachel jokingly dubbed "the poor man's Rhododendrons". Funny, the bayberries do have a rounded form and an almost evergreen waxy leaf, and they're a heck of a lot faster growing and easier to keep alive than rhododendrons.
Bayberry seems to tolerate almost all conditions -- dry, wet, saline -- and it's deer resistant. I've found it growing in abundance in sandy coastal soils, but also peppered into moist clay meadows in the Sourland. As a nitrogen fixer (in association with Frankia bacteria), bayberry has an advantage in poor, leached, depleted, and other difficult soils.
So bayberry is a tough customer -- except for one factor. It is not very shade tolerant, and once the canopy closes in, bayberry winks out, mission accomplished.
As the class and I considered the bayberry in the woods, we looked at the surrounding pin oaks. Soon this woodland would coalesce and the bayberry would be shaded out. It was an indicator of what had gone before -- an open scrub with scattered shrubs, herbs, and grasses, and one of the last clues we needed in confirming that landscape's history.
*Note the name change. Until recently, this species and its congeners were known under the genus Myrica. Which I happened to like better, but oh well.
 Place, Allen R., and Stiles, Edmund W. "Living Off the Wax of the Land". The Auk 109(2), 1992
Bayberry, surrounded by fall color, Plainsborough, NJ