You can’t drive very far right now without seeing a sea of tiny, white flowers belonging to an invasive plant, Wild Chervil (Anthriscus sylvestris), crowding the shoulders of the road. A member of the carrot family, Wild Chervil leafs out early in the spring before most native plants and consequently shades them out and displaces them. It spreads aggressively and produces many seeds that are dispersed by birds, water and mowing (after the seeds have set).
Native to Europe, Wild Chervil was introduced in the early 1900’s to North America in wildflower seed mixes intended to reproduce the European countryside in gardens. Little did gardeners know that among these seeds was a plant that would outcompete native plant species and drastically reduce wildlife habitat. In addition to choking out native plants, Wild Chervil also is the host for a virus that infects carrots, parsnips, and celery.
Because it is a prolific seed-producer Wild Chervil can be challenging to eradicate. The best way to control it is to stop it from flowering and setting seed, but unless you mow early, every year, before its flower buds open, this isn’t a very effective method. Its up to six-foot-long taproot makes removing it by hand extremely difficult, but possible; however, this method also runs the risk of breaking off lateral buds at the top of its roots that can grow into new plants. Beware — Wild Chervil looks a lot like Poisonous Hemlock (Conium maculatum).
One of the few positive things to be said about Wild Chervil is that its flowers are a source of nectar for small bees, parasitic wasps, flies and beetles. Black Swallowtail larvae feed on the foliage. Many of these flowers are being visited now by thousands of flies in the Bibionidae family. Pull over the next time you see clouds of white smothering the edge of a road and look for these tiny, black flies. The males are the ones with the big eyes (pictured).
Japanese Barberry, Berberis thunbergii , is very much like the shrub Burning Bush, Euonymus alatus – it comes into its own in the fall, turning many shades of red and orange, and thus has had great appeal as an ornamental. Birds, including turkeys, grouse, mockingbirds and waxwings, find the fruit of this woody shrub irresistible, and spread the seeds far and wide – a bit too far and wide, in fact. Like Burning Bush, Japanese Barberry has escaped from cultivation and is established and reproducing in the wild so successfully that it is classified as invasive. It is a particular threat to open and second-growth forests. An established colony can eventually grow thick enough to crowd out native understory plants, reducing wildlife habitat and forage, thereby increasing pressure on native plants by white-tailed deer and other herbivores. According to Pennsylvania’s Dept. of Conservation and Natural Resources, Japanese Barberry also acts as a nursery for deer ticks, which can transmit numerous diseases.