Return of the Shrubs

The good news is that our shrub layer is making a comeback in some places.  The bad news is that most of the shrubs are growing in places inaccessible or inconvenient to deer.

Take common elder.  When we first moved here, 36 years ago, a line of common elder shrubs grew behind a barberry hedge that stretched sixty feet from our chicken shed to the guesthouse.  Several more common elder shrubs thrived at the bottom, wet edge of First Field.  Every year I had more than enough clusters of purple-black berries to make several batches of elderberry jelly.  But without my noticing, those shrubs gradually disappeared.  No doubt they had reached the end of their lifespan, or so I thought.

I missed their lovely flowers “foamed over with blossoms white as spray,” as poet James Russell Lowell once described them.  Also known as “sweet elder” and “American elder,” few of our native shrubs are as widespread, abundant, and well-known,” Pennsylvania author William Carey Grimm wrote in The Book of Shrubs, back in 1957.  Because this native shrub grows from Nova Scotia to Manitoba, its species name is canadensis (of Canada), but it also ranges as far south as Georgia, Louisiana and Texas.

Common elder was once called the “medicine of the common people,” and elderberry juice was used for treating a wide range of problems including arthritis, gout, diarrhea, coughs, and colic.  More recently, scientists discovered that common elder is extremely high in Vitamin C.

The late Pennsylvania writer Euell Gibbons, in his classic Stalking the Wild Asparagus, gives instructions for making cough medicine from elderberry juice and face cream from elder flowers.  He, like I, tried to use elderberries in pies and discovered that they tasted “pretty nauseous.”  Gibbons recommends drying the berries, which, he says, “eliminates the rank elder taste.”

I never did experiment with drying the berries, but maybe I will now that we once again have a line of elderberry shrubs bearing fruit.  Unfortunately, every one of those shrubs germinated inside our three acre deer exclosure.  Only when I saw them thriving there did I realize what had happened to our original, unfenced common elder hedges.

The common elder genus name Sambucus comes from the Greek “sambuca,” which is purported to be a stringed instrument made from Sambucus racemosa–the red-berried elder.  That too is a common shrub in Pennsylvania and, unlike the common elder that blooms in late June and July, the red-berried elder displays pyramid-shaped clusters of white flowers in late April or early May.  The red-berried elder, also a European species, is labeled with the variety name pubens in North America, and is found from Alaska to Newfoundland and south through the Appalachians to Georgia.

It has a bevy of common names, a few of which are “red elder,” “scarlet elder,” “mountain elder,” “red elderberry,” and “stinking elder.”  Red-berried elder grows in cool, moist, rocky woods and ravines.  When it is fruiting, in late June and July, its showy, scarlet berries are a favorite food of birds such as rose-breasted grosbeaks, eastern bluebirds, gray catbirds, and American robins as well as chipmunks, woodchucks, foxes, squirrels, and rabbits.  Somehow, they can withstand the cyanogenetic glycoside and an alkaloid in the berries that make us nauseous or can cause vomiting, diarrhea or gastrointestinal pain.  But dyes have been concocted from the fruit, bark and stems and an insecticide from dried leaves.Last spring I found several red-berried elders growing on the tip-up mounds of uprooted tulip trees, on the steep slope below Ten Springs Trail, and on the Far Field road bank, where they are protected by piles of ice-storm broken branches.  All those places are inaccessible to deer. On the other hand, below the forks on a flat area beside our stream, which is accessible to deer, I found many small red-berried elder shrubs plus spicebushes and witch hazel trees last April.

Both elder species are members of the Honeysuckle Family.  So too are three other native shrubs struggling to survive on our mountain.  Two are viburnums.  The viburnum genus, as a whole, is favored by deer, but I found a couple black hawks (Viburnum prunifolium) in bloom at the edge of the Far Field a couple years ago.  Also known as “stagbush,” “nannyberry,” “sheepberry,” and “sweet haw,” its species name means “plum leaf,” which describes the appearance of its leaves.  It has flat-topped clusters of white flowers that appear in May or June, and birds and mammals eat its dark, bluish-black, oval-shaped fruits that ripen in early fall.

We also have maple-leaved viburnum (V. acerifolium) growing sparsely on our road bank and abundantly in our deer exclosure.  It used to be a frequent understory shrub in Pennsylvania’s deciduous forests.  Named for its maple-shaped leaves, its flat-topped, white or pink-tinged clusters of flowers bloom from mid-May until mid-June, and its bluish-black fruit ripens in September.  But the fruits are not particularly palatable, and only a few birds bother with them.  Other names for maple-leaved viburnum include “flowering maple,” “squashberry,” “dockmackie,” “guelder-rose,” and “possumhaw,” so perhaps the latter name implies that opossums eat the fruits.

The last shrub member of the Honeysuckle Family on our property is bush-honeysuckle (Diervilla lonicera), which I found blooming on the road bank on June 24.  Because it is popular summer browse for deer, I was delighted to discover several shrubs with terminal clusters of funnel-shaped, pale yellow flowers.  Also called “dwarf bush honeysuckle” and “yellow flowered upright honeysuckle,” it is not a true honeysuckle at all even though its species name lonicera, which is Latin for “honeysuckle-like” appearance, is the genus name for true honeysuckles.  It ranges from Newfoundland to Saskatchewan, south to Iowa and the Great Lakes, east to Delaware and, in the mountains, as far south as North Carolina.

For years our rocky road bank has also provided refuge for wild hydrangea (Hydrangea arborescens), a member of the Saxifrage Family.  Slowly it has moved up the hollow, providing plentiful flat-topped clusters of creamy-white flowers that light up our forest roadside in June and July.  Occasionally, we find a few larger, sterile flowers, which usually blossom on cultivated hydrangea called “Hills of Snow.””Hydrangea” means “water vessel” in Greek because of the cup-like shape of its dried fruits.  Supposedly it is poisonous to livestock, but the deer don’t seem to mind nipping it.  Its species name arborescens means “becoming tree-like,” a reference to its becoming woody with age, hence its alternate name “tree hydrangea.”  Another name is “seven barks” because its stem bark peels off in several layers of thin, different-colored barks.

One sad shrub loss that has nothing to do with deer-grazing is that of our abundant mountain laurel (Kalmia latifolia), a member of the Heath Family.  Ed and Maureen Levri, both in the Biology Department at Penn State Altoona, are studying mountain laurels inside and outside our deer exclosure.  They suspect that its spotted leaves and, in many cases, subsequent death are due to a leaf fungus.  Many mountain laurel shrubs still survive, especially on the powerline right-of-way, but in the depths of the forest I can find almost as many dead shrubs as live ones and even those look unhealthy.  No longer do they provide the dense deer cover they used to, and their lavish display of blossoms every June is only a memory.

On the other hand, we are seeing the recovery of another member of the Heath Family, the rhododendron (Rhododendron maximum), also known as “great laurel” or “rose bay.”  High on Laurel Ridge, several hundred feet above our stream, Rhododendron Trail winds through dozens of large (eight to ten feet tall) rhododendrons.  All have grown beyond the reach of deer browsing, just as those few have that overhang our stream and road bank.

A few more large rhododendrons grow beside Guesthouse and Black Gum trails.  Other, small ones have struggled for years to get above deer height and have been grazed down to the nubbin in most cases.  Then, a couple years ago, I noticed new shrubs sprouting and thriving along Laurel Ridge Trail and only occasionally being nibbled by deer.  At the same time, what had been a bare slope above Rhododendron Trail was green with newly-germinated rhododendrons.  So far not one has been grazed.

Although deer continue to eat rhododendron, particularly in the winter, it is not a favorite food.  But Grimm did write in The Book of Shrubs that “in many sections of the state, where deer are entirely too numerous, the shrub is often browsed to excess,” so we believe that our recovering rhododendron may be a sign that our hunters’ diligent harvesting of more than 40 deer every year on our square mile of mountain land is having a positive effect on our shrub recovery.

Our mountain azalea (Rhododendron prinophyllum), also known locally as “wild honeysuckle,” is another member of the Heath Family that ranges throughout the rocky woods of Laurel Ridge.  Its bright pink flowers perfume the forest in May.  Usually I smell it before I see it, so intense is its clove-like fragrance. Both inside and outside our deer exclosure, new shrubs have sprung up, and I am hopeful that it too will make a comeback.

Still, the problem with most shrub species is that they “never outgrow the reach of deer, and so remain vulnerable to browsing throughout their lifespan,” as botanist Ann F. Rhoads wrote in her Game News article, “Something is Missing” back in August 1996.  She especially mentions the loss of witch-hobble (Viburnum alnifolium), American yew (Taxus canadensis), and red-berried elder as “just a few of the shrubs that have disappeared from areas where they used to be abundant in the forest understory.”

Many studies show that in order for our shrub layer to recover, we must have less than ten deer per square mile.  Without the large predators our forests once had to keep the deer numbers down, as we did during Colonial times when it is estimated that we had between eight and eleven deer per square mile, we must depend on good hunters to do the job.  Only then will our forests have all the components they need to grow and thrive and produce both food and cover for an abundance of songbirds and mammals.