Invasive Species Awareness Week: Don’t Let These 3 Plants Creep Up on You!

National Invasive Species Awareness Week is February 24-28! This is a time to bring attention to what invasive species are and why it’s worth the effort to prevent them. 

Invasive species are organisms (plants, pests) that are not native to our area and cause harm to the environment, economy, and/or human health. Invasive plants, for example, can take over and out-compete native plants. This affects other species that rely on those plants for food and survival. Invasive species are challenging and expensive to remove! 

Here we highlight three plants that are highly invasive in Montgomery County. These are often present around home yards, schools, congregations, and parks. As the name invasive suggests, they spread into just about anywhere!

English ivy leaves – Source: James H. Miller, USDA Forest Service, Bugwood.org

English ivy  

English ivy (Hedera helix) is an evergreen plant that has been used widely as a decorative ground cover. An interesting fact about English ivy is that it has two life stages: juvenile and adult.

• Juvenile stage English ivy spreads out vigorously on the ground and doesn’t produce flowers or seeds.  

• Adult stage English ivy occurs usually when the ivy climbs up vertically (such as on trees). It produces flowers and then berries that are eaten by animals that deposit the seeds in their poop.  

• English ivy spreads out of bounds at both stages! 

You can see English ivy climbing and damaging trees in many neighborhoods and County parks. Avoid planting it. If you have English ivy, keep it from climbing up trees and other surfaces, and consider gradually replacing it. There are many other options for ground covers that are beautiful and beneficial. Learn about other options for ground cover. 

Invasive bamboo – Source: Frank Jurcik, Bamboo Invasions, Bugwood.org

Running Bamboo  

Running bamboos — the tall, stalky plants that many people know as the preferred food of Pandas — have been used in landscapes to create thick green privacy screens. The problem is that running bamboo doesn’t stay put! It spreads very aggressively and many people (and their neighbors) regret that it was ever planted. It is very difficult to stop or remove.  

Last year, a Maryland state law was passed to allow local jurisdictions to manage bamboo and we are working on steps for how bamboo could be better managed in the County. If you have running bamboo, the University of Maryland Extension has good information on ways to remove or contain it. There’s also a helpful page about alternative plants for green privacy screens. 

Lesser celandine flowering – Source: Pixabay stock

Lesser Celandine 

Lesser celandine, also called Fig buttercup (Ficaria verna), is a pesky ground-covering weed that’s terribly invasive along some streams in our County. In some cases, it completely smothers the ground and prevents native plants from growing. It also gets into home lawns, especially those that are compacted or shaded.

You may see this plant’s shiny leaves and yellow flowers as early as February and then it appears to die in the summer heat. But it doesn’t really go away! Its sneaky super-power is its tiny bulbs the lie underground all year, enabling it to come back again and spread further.  

Lesser celandine is one of four invasive species that have an exemption under the County’s Pesticide Law. In other words, yes, you can use a systemic herbicide to kill it (but be sure to read and follow the herbicide label instructions for precautions). Try manual removal first, by digging out the whole plants and bulbs. Learn more about the exemption. Learn more about the Pesticide Law. 

Lesser celandine has invaded a forested area. Source: MoCo.gov RainScapes

Montgomery County RainScapes planning specialist Daniel Somers shared two tips for managing invasive plants in general: 

1. Manual removal can effectively eliminate plants by exhausting their energy reserves. Regular mowing or weed whacking of new shoots forces the root system to deplete its stored energy, eventually leading to the plant’s death. While this method may not be ideal for large infestations like bamboo or lesser celandine, it can be quite effective for smaller outbreaks of other invasive plants (like English ivy) on private property — without relying on chemicals. 
2. After removing invasive plants, it is essential to stabilize the area to prevent further issues. Consider planting a new garden, or simply seeding and covering the area with straw to prevent erosion and discourage the germination of new weed seeds. 

The state of Maryland is currently working on new regulations to prohibit the sale of invasive plants. 

Here in our County, conservation landscapes  and rain gardens approved by the RainScapes program to manage stormwater also prohibit the use of invasive plants. 

Some additional resources to help on this topic: 

• Montgomery County Invasive Species of Concern (PDF) 

• Plant Invaders of Mid-Atlantic Natural Areas Field Guide 

• Ask Extension, a free service from the University of Maryland Extension, is available to all Maryland residents. Send pictures of your invasive plant(s) and get advice about how to manage them in ways that minimize herbicide use. 

Lastly, if you can lend a hand, become a certified Weed Warrior and help remove invasive plants in Montgomery County parks!