Crow’s Nest: Invasives Talk at Waterloo Mills

May 3, 2011

This weekend I had the pleasure of joining Kevin Fryberger of Brandywine Conservancy to co-lead a walk at their Waterloo Mills Preserve on the topic of managing invasive plants. We had done this once before, several years ago, and it was exciting for me to see the progress he has made in reducing the number of non-native invasive species and increasing the diversity of native plants.

Over the last decade he has converted a large turfgrass area to meadow and the bare edges of a pond to a shrub and tree thicket. Kevin is an avid birder and he joked, “I’m like a dog, easily distracted by sights and sounds,” and he peppered his talk with, “There’s an ovenbird… overhead are two orioles… and by the way, this native plant is one they are completely dependent upon.”

Kevin emphasized timing in controlling invasive plants: since many invasive species leaf out earlier than our natives there is a window of opportunity to control them in the spring without impacting native wildflowers and shrubs. Other windows exist in the summer and fall that allow us to exploit the unique physiology of the plants. As we walked around his preserve we saw a few invasive plants, but far fewer than there used to be, and far less than there would have been with no management.

Some of the natives regenerate naturally. In the areas where he killed turfgrass and prevented stiltgrass from germinating, some native¬†Eupatorium, Carex, and Helianthus came in on their own. (At Crow’s Nest I am amazed by the wildflowers, particularly nodding trillium, that have shown up on their own in a section of woods where I have been removing garlic mustard.)

Other species need more encouragement, and Kevin has planted many of the shrubs around the pond. A highlight for me was how he planted a circle of buttonbush shrubs (Cephalanthus occindentalis) to protect a Canada lily inside from deer browse.

Many of us on the preserves work on our own and it is always a pleasure to compare notes with others doing similar work.