Invasive plants are attempting to take over our forests and fields. From winged euonymus (burning bush) and Japanese barberry to oriental bittersweet, multiflora rose and autumn olive, our region is becoming overgrown with harmful invasive plants.
I have written about these problematic plants and the damaging impact they have on the natural habitat of our fields and forests in past columns.
It is not that these plants are harmful to humans or animals – in fact many have tasty seeds and fruit birds and small mammals devour. They, however, have a negative impact on our native plants due to their ability to out-compete them for soil and sun. The non-native invasive flora can, literally, overtake an entire forest understory or open field. They truly are “invasive” to our natural habitats.
It seems the more I know about these terrestrial invaders, the more I see them. I am like the young boy in the movie “The Sixth Sense” when he said, “I see dead people,” but for me it’s “I see invasive plants.” I know if I walk from my house down our road for about 100 yards, I can easily spot every invasive plant listed above.
Which brings me to my newest plant nemesis, and one I have recently battled on forest property my family owns in southwestern New Hampshire. About five years ago, I first discovered buckthorn growing in an open area at the edge of our property. The small field was in full sunlight and full of wild plants such as blackberry, goldenrod and Queen Anne’s lace. What caught my eye was a shrub about 10 feet high covered with dark berries that at first, I thought might be choke cherry. I later discovered it was buckthorn, and by then it had begun to spread to other open areas of the property.
According to information found on the Natural Resources Conservation Service website, there are two types, common buckthorn (Rhamnus cathartica) and glossy buckthorn (Frangular alnus).
Buckthorn is native to Eurasia and was probably introduced into the United States before 1800 but did not become widespread until the early 1900s. Today, it is found throughout most of central and northern United States and into Canada.
Both common and glossy buckthorns are shrubs or small trees that readily invade natural areas, establishing dense, even-aged thickets, which crowd or shade-out native plants. Buckthorns reproduce by seed and through root suckering. They produce fruits which are readily eaten, therefore the seeds are spread by wildlife, especially birds.
Buckthorn typically leafs-out early and retain its leaves longer than native shrubs, giving it a photosynthesis advantage over native plants. With alternate leaves of 1-3 inches in length, buckthorn has tiny flowers, each with five whitish or greenish petals and small fruit berries with two to three seeds that ripen in mid-summer. The fruit starts green and then turns to purplish-black color. The inner bark of the shrub is yellow in color.
There are several ways to control buckthorn. Young sprouts can be pulled by hand, especially when they first appear. Larger plants should be cut however, because the plant is prolific at root suckering, so cutting alone is not sufficient to control it. My experience and research have shown me the best way to control buckthorn is to cut the plant with a saw, brush cutter or lopper and treat the cut stems with herbicide. Cutting can be done in summer after the tree has set leaves, but before fruiting to prevent regeneration by seed. Or, it can be done in late summer or early fall.
Monitoring and controlling buckthorn should be an annual process, just as it is for other invasive plant species, such as Japanese barberry, oriental bittersweet and winged euonymus (burning bush). They are persistent, and landowners must be as well.
I have found buckthorn along the roadside near our house in Putnam, as well on the edges of our horse pasture. I also know of large stands of it at a land trust property in Hampton. I first became aware of it in New Hampshire, and it seems to have followed me home to Putnam to torment me here as well.
Two years ago, we undertook a timber sale at our New Hampshire property. After decades of careful forest management, the wooded land is again more open with substantial sunlight reaching the forest floor. The life-giving sun and rich soil has brought life to seedlings of red and white oak, sugar maple, yellow birch, beech, and white pine. Last summer, I found tiny oak and maple seedlings among the stumps of recently harvested trees. The regeneration of the forest is underway for future generations of Reids to enjoy and carefully manage.
Unfortunately, I also discovered buckthorn sprouting in the newly opened forest, and it is growing faster and seemingly more vigorous than the slower growing native hardwoods. The long-term health of our forest is at risk, as is the type of forest we will bequeath to our children and grandchildren.
Our family has owned the property since 1933, and since the late 1960s we’ve engaged certified foresters and created forest stewardship plans to manage the wooded property. We undertook a series of timber harvests to improve the health of the forest as well as to provide funds needed to maintain the buildings on the property. New roofs, siding, paint, refurbished rooms, a new septic system and upgrades to heat and electrical have all been completed with monies provided by the forest trees.
If we are to provide for those who come after us, we must now accept a new challenge of controlling invasive plants and shrubs. We need to educate ourselves and become more in-tune with what is happening in the forest. The fact is, a well-managed forest is a healthy forest; and a healthy forest requires the vigilance of owners and managers to hold back the invasive non-native plant species.
We have received advice through site visits from the Cheshire County Extension Service Forester and naturalists from the N.H. Natural Resources Conservation Service and N.H. Fish and Game. Their advice has been extremely helpful as we look to the long-term process of actively managing our forest.
Last fall and this summer, I began cutting buckthorn and treating the cut stems with herbicide to prevent re-sprouting. I am finding it in many parts of the forest where it was not before. This is of great concern to me and my family, but we are up to the task and take our responsibility as forest land stewards very seriously.
We are lucky to live in a beautiful region called The Last Green Valley. The fields and forest are relentless in growth and regeneration. Unfortunately, many types of invasive plants have moved into our region and are seemingly even more relentless than our native plants. The challenge is on, and I hope you’ll join me and others in learning about the negative impact invasive plants are having on our fields and forests.
Bill Reid is the Chief Ranger of The Last Green Valley National Heritage Corridor and has lived in the region for more than 35 years. He can be reached at email@example.com.