What are Non-Native Invasive Plants?

University of Maryland Extension: Introduction to Invasive Plants

Most natural communities support a great variety of native plants and animals. Such biodiversity is threatened when a few plant species take over and dominate the herbaceous, shrub, or canopy layers of a forest.

Non-native, invasive plant species (NNIs) can alter the complex webs of plant-animal associations that have evolved over thousands of years to such a degree that plants and animals once familiar to us are eliminated. In meadows, for example, NNI monocultures can threaten butterfly populations because they can no longer find the native host plants they depend on for survival. In forests, NNI vines can strangle and smother trees. NNI shrubs can displace and shade out native plants that provide birds and other wildlife with food and shelter. Recent research has shown that NNIs can even alter soil chemistry and disrupt the growth of the mycorrhizal fungi on which healthy forests depend. In short, NNIs are causing significant changes in the composition, structure, and ecosystem function of our natural areas.  NNIs are considered by some analysis to be as harmful to global biodiversity loss as straight up habitat loss (think car parking lot).

A typical NNI plant has some or all of the following characteristics:

  • Grows fast and matures early.
  • Spreads quickly over large areas.
  • Thrives in many habitats.
  • Reproduces profusely by seed and/or vegetative structures.
  • Survives and produces seeds under adverse environmental conditions.
  • Has few known diseases or pests.

By their very nature, NNIs are difficult to control. Often it requires a mix of mechanical, chemical, and hand removal efforts to be successful. The key is to find NNI populations when they are small and remove them before they become established. This is why it is important that we start this work immediately.

Examples of NNIs currently on Bannockburn ES Grounds

Amur Honeysuckle, (link), Winter Creeper (link), Oriental Bittersweet (link), English Ivy (link), Wineberry (link), Bamboo (link), Japanese Holly (link), Chinese Holly (link), Porcelain Berry (link), Japanese Honeysuckle (link).