CA’s Invasive Plant Resource and Reference Guide

Invasive plants are a serious threat to the health of Columbia’s natural areas. Why? Without native controls like deer or insects eating them, they spread quickly and out-compete native plants. This decreases biodiversity and causes major disruptions in the ecosystem.

Every day, CA’s team is working in areas that are heavily infested with invasives to improve the habitat for native plants, animals and insects. With hundreds of invasives spread across 3,600 acres of open space, building a healthier ecosystem requires a community effort.

How YOU can help stop the spread

The best thing you can do is avoid planting invasives in the first place. Want to learn about native species that are safe to plant? Click here for a list of recommendations from the University of Maryland Extension. You can also get involved and learn more by joining CA’s Weed Warrior volunteer group, where dedicated residents lend a hand with invasive weed removal across Columbia.

If you do come across invasive species in the community, it’s important to recognize that each invasive plant species has distinct characteristics, timing and methods of control. Understanding the characteristics of individual plants will increase your success in controlling and limiting their impact.

That’s why CA is maintaining this resource and reference library: To provide current, research-based best management practices and control methods. Our expert team has vetted the following resources from our trusted partners about common invasive plant species found in Columbia.

Invasive shrubs

Invasive trees

Invasive vines

Invasive grasses and forbs

Control calendar

Virginia Department of Forestry Control Guide

Invasive plant identification

Mistaken identity? Invasive plants and their native lookalikes - an identification guide for the mid-Atlantic

Common invasive plants Easy ID Cards — Common invasive plants easy ID cards

Other common invasive plants found in Columbia:

Invasive plant alert!

In addition to managing over 30 common species of invasive plants, CA Open Space practices early detection rapid response to prevent new invasive plant infestations from becoming widespread. Prevention of new invasions is the most cost-efficient and least expensive invasive plant management strategy.

There are a few invasive species that are particularly harmful to our ecosystem, and require rapid attention. If you observe the following species in Columbia, please contact CA’s Conservation Landscape Specialist Eric Walker at eric.walker@columbiaassociation.org.

Purple loosestrife (Lythrum salicaria): Currently detected at Jackson Pond, Lake Elkhorn and Wilde Lake. Threatening to spread further into riparian systems and wetlands in Columbia. Purple loosestrife has bright purple flowers, oblong or lance-shaped leaves and square stems.

Japanese knotweed (Fallopia japonica): One infestation known to occur east of Lake Kittamaqundi. Knotweed can permanently alter and damage entire watersheds.  Invasive knotweed forms dense patches and is very difficult to remove once established. Japanese knotweed has hollow, cane-like stems (may resemble bamboo) and leaves that are heart to spade-shaped, arranged alternate on stem.

Poison hemlock (Conium maculatum): Known to occur throughout Columbia, this plant is highly toxic to humans if ingested and can be mistakenly confused with common edible garden plants like carrots and parsley. Due to the serious health concerns and public safety risk of accidental consumption, we are tracking occurrence and assisting with control measures in Columbia. Poison hemlock has clusters of white umbrella-shaped flowers, purple splotches along mature stems and a large, white, carrot-like taproot.

Kudzu (Pueraria lobata): No known infestations have occurred in Columbia – yet. With the distribution of kudzu in our area, it is only a matter of time until this well-known invasive plant shows up here. This invasive vine has caused widespread destruction in the southern United States. When we find it in Columbia, we want to rapidly control this plant and prevent the infestation from spreading. Kudzu has reddish-purple, pea-like flowers and the leaves can vary in appearance (generally, the stems have three leaflets).

Thank you!

We truly appreciate your help protecting Columbia’s ecosystem from harmful invasive species. Again, if you have any questions, don’t hesitate to reach out to CA’s Sustainability Team at sustainability@columbiaassociation.org.