Why should I be concerned about Invasive Alien Plant species?

Plants that are not native to their environment are called “Invasive Species” for obvious reasons – they don’t belong.
Invasive species are harmful to our natural resources (fish, wildlife, plants and overall ecosystem health) because they disrupt the checks and balances that form the complex web of life. Approximately half of the poisonous plants in the eastern U.S. in non-agricultural areas are non-native and many are invasive.¹ Bees and butterflies benefit our food and eco systems while loss of native plants affects their survival.
Invasive Species have a tendency to spread out of control and cause a variety of damage to the economy and even our health. In Virginia we have 350 types of trees, vines, shrubs, grasses and herbs that don’t belong.²

Two of the most common invasive species you’ll see in our area are Garlic Mustard and English Ivy. In the late 1800’s, garlic mustard was brought to the United States from Europe for use as a culinary herb. English Ivy was brought to the United States by European colonists as an ornamental plant in the 1700’s and is still sold in garden stores today. All of this sounds innocent enough and one’s thoughts turn to sautéing garlic mustard or making tea out of the ivy. Both are feasible – but that’s a conversation for another time, a cook-off anyone?

The reality is, Garlic Mustard produces a toxin that kills necessary root-coating fungi on our maples, oaks and beech trees. Garlic mustard inhibits the germination of many native plant species seeds, including many spring wildflowers. English Ivy kills off local vegetation. The vine can attach to a tree trunk, climb its way up, cover the leaves and branches, prevent it from getting sunlight and extinguish its life.

Why are Invasive species a new concern at Oakbrook?

In the dense urban environment of Reston we have a very special gift on our Oakbrook property. Roughly half of it is forest. Through our stream monitoring work and training via watershed specialists we know the best place for rain to land is on forest. Trees, shrubs and plants filter out pollution and their root systems keep the watershed balanced. God created a perfect system.

Man made, impervious surfaces (driveways, roads, parking lots, etc.) are unhealthy for a watershed. They are very effective at carrying pollution into our ground water and are equally precise at eroding stream banks and washing away beneficial insects. We have several impervious surfaces large enough to matter on our property, essentially the parking lot and the roof of our building. Many years ago when our church was remodeled Fairfax County recommended and OC followed through with in-ground downspouts from our roof and drains from our parking lot that all flow directly into our wooded area.

In December of 2015 we had the Northern VA Soil and Water Conservation Districts Watershed specialist, Dan Schwartz, study our property. What we found was exciting. Dan pointed out that there are no signs of erosion in the woods, hence the pollution coming from our roof and parking lot can be considered contained and filtered right here on our property.

In recent months one of our stewards saw that we had invasive plants encroaching on this vital island of life. As Stewards of Creation we want to keep our forest thriving so we will gather for an Invasive Species Pull. Once we’ve yanked them out our native trees and plants can breathe easier, continue to thrive and remain a huge benefit to our watershed and community.

1 https://www.fws.gov/invasives/faq.html#q2
2 Invasive Alien Plant Species in Virginia (Department of Conservation and Recreation and the VA Native Plant Society.)