Garden Alert

Garden Alert: Are these new invaders in your yard?

The list of invasive plants in Arlington County is always expanding. There are many reasons for adding a new species to Arlington’s invasive plant list, including new species sightings in our parks and natural areas, as well as demonstrated “invasive qualities” of a particular species in other jurisdictions in the mid-Atlantic region or locations with a similar climate.

Arlington’s list includes both “invasive” and “threat” plant species. “Invasive” plants are those that have been documented as non-native plants that spread into natural areas and cause negative impacts. All plants that have been categorized as “invasive” on our list have been found in Arlington County. Plants categorized as “threat” are species that are included in other invasive plant lists in our region but haven’t be documented in Arlington County, yet.  “Threat” species also include aggressive non-native plant species that have been found in Arlington County but are still being surveyed to access their negative impacts to natural areas.

Many new invaders and “threat” plant species are attractive ornamentals that are used in home landscapes. Due to their invasive tendencies, these plants should not be planted. If they are already present, it is wise to remove them before they can escape into natural areas. In the short-term, remove the fruiting parts of the plant to keep them from spreading. This isn’t possible for certain species of grasses or trees due to their large number of fruits.

The following plants have all been found in Arlington County Parks in the past few years and are transitioning from “threat” to “invasive” plant species. We are working to remove them from ornamental plantings around the County.  Do you have them in your garden? If so, check out the linked fact sheets from the National Park Service to find information about how to remove them.

Grasses and Herbaceous Plants

Fountain Grass
Pennisetum alopecuroides
Fountain Grass

Bugwood.org

 

 

 

 

 

 

 

 

 

Yellow Archangel
Lamiastrum galeobdolon
Yellow Archangel

Missouri Botanical Garden

 

 

 

 

 

 

 

 

 

 

Creeping Lilyturf
Liriope spicata
Creeping Lilyturf

Bugwood.org

 

 

 

 

 

 

 

 

 

 

 

 

Shrubs and Trees

Orange Eye Butterflybush
Buddleja davidii
Bugwood.org

Bugwood.org

 

 

 

 

 

 

 

 

 

 

 

 

Wintergreen Barberry
Berberis julianae
Wikimedia.com

Wikimedia.com

 

 

 

 

 

 

 

 

 

 

 

Pagoda Tree
Styphnolobium japonicum
Bugwood.org

Bugwood.org

 

 

 

 

 

 

 

 

 

 

 

 

The following internet links are considered reliable information resources on invasive plant species in our region and around the country:

Invasive Alien Plant Species of Virginia (DCR)

Center for Invasive Species Ecosystem Health Invasive Plant Atlas

Mid-Atlantic Exotic Pest Plant Council Plant List

Invasive Plant Atlas of New England

Southeast Exotic Pest Plant Council Invasive Plants of the Southeast

 

Comments

  1. Bernie Berne says:

    Orange Eye Butterfly Bush (Buddleja davidii) should not appear on any invasive species list in Arlington County. The species is only rarely found in the wild in the National Capital Region and never (in my experience) in substantial numbers. It may be invasive somewhere in the world, but local conditions are clearly not conducive to invasiveness.

    The 2010 edition of the National Park Service’s book, “Plant Invaders of Mid-Atlantic Natural Areas” describes the this species as follows on page 136: “Orange eye butterfly bush, or summer lilac, is native to northwestern China and was introduced into North America around 1900 for ornamental purposes. It escaped from plantings and occurs in scattered locations in the Northeast, Southeast and Mid-Atlantic and in the western U.S. from Southern California to northern Washington.”

    The table of contents on page 5 of the NPS book places the species in its list of “Plants to Watch”, rather than in its list of invasive species.

    Buddleja davidii attracts large numbers of butterflies and other polllnators. Monarch butterflies and honeybees frequent it. It is therefore important to the survival of these and other pollinators. The species’ occurrence in “scattered areas” in natural area cannot and does not outweigh its importance in maintaining pollinator populations, some of which are rapidly declining).

    Individual Buddleja davidii have reportedly been found in Arlington parks in recent years. However, this does not provide sufficient evidence to demonstrate that the species is “transitioning” from “threat” to “invasive”.

    Arlington County should therefore following the NPS lead of classifying the species as one to watch, rather than as one that is invasive within the County.

    This species has been in the U.S. for more than 100 years. Despite this length of time, the species is still occurring only in “scattered locations” in natural areas within the U.S,

    The Arlington County government should therefore encourage County residents to plant this species to help pollinator populations, rather than to encourage the species’ removal.

    Identifying the species at this time as one to be removed in Arlington County is clearly misguided. There is presently insufficient evidence to conclude that the species is becoming invasive in the National Capital Region or that its potential for harm to the County’s environment exceeds its demonstrated benefits.