Remove Invasive Plants

Removing invasive plants from your property helps to protect wildlands

Our nation’s forests, our coastlines, and our regional and national parks are at risk from invasive plants that escape from our home landscapes. These invasive species stress the woodlands, prairies, deserts, and waterways that are our greatest natural resources. The good news is that when you remove invasive plants from your property, you help to prevent the spread of these invaders and help to protect your local wildlands.

Still widely planted: The Norway maple (Acer platanoides; left) outcompetes native saplings preventing native forest regeneration. Roots that grow close to the surface inhibit the forest's native understory growth along with the populations of animals and organisms that depend on a rich, native plant-filled ecosystem.

Fast food joint for butterflies? As its name implies, butterfly-bush (Buddleja davidii aka Buddleia davidii; right) is a butterfly magnet. The jury appears to be out regarding the quality of the nectar, but the troubling concern is this plant's tendency to escape our home landscapes and invade forests displacing native plant communities. Luckily, the many beautiful native alternatives make eliminating butterfly-bush from our landscapes an easy decision.

Beauty and the (lack of) beasts: It is hard to deny the visual appeal of purple loosestrife (Lythrum salicaria aka L. virgatum; left and below), but its rampant spread has a devastating impact on wetlands and waterways smothering large areas of native grasses, cattails, and rare aquatic plants that wildlife depends on. Without a source of food, cover, and reproduction sites, native communities of animals and micro life cannot survive.

Plants that are introduced to a country or region are considered non-native, alien, or exotic species. When restoring landscapes to wildlife habitat, introduced plants occupy space in the landscape that otherwise could be used by native plants that offer significantly more wildlife support. Far more worrisome are the introduced plants that compete aggressively and cause extreme damage to the natural ecosystems they invade. These aggressive plants are called invasive species.

Invasive plant species outcompete and often kill the native plants they overtake. When a native plant species disappears from an ecosystem, the wildlife depending upon it will also disappear. Unfortunately, there are numerous species of invasive plants including many that are still available for purchase. In this action, we share tools to help you identify the invasive species you are most likely to encounter and offer ways to remove them to make room for native plants that will welcome and support the wildlife in your yard.

Asiatic bittersweet (Celastrus orbiculatus) is an aggressive, invasive vine that climbs up trees weighing down and breaking branches and strangling trees to death.

A single plant of stiltgrass (Microstegium vimineum) can produce up to 1,000 seeds that are viable (alive and able to germinate) for 3 years or more. Such prodigious seed production makes it very hard to keep up with removal.

Some plants in the Aster family (Asteraceae) such as thistles produce pappus (fluffy tufts attached to each seed) that work like a parachute to carry the seed away in the wind.

Birds feast on the berries of invasive plants such as this Amur honeysuckle (Lonicera maackii). Later the birds fly away and deposit the seeds elsewhere.

People and lawn mowers spread seeds embedded in the mud on their shoes and tires. Some invasive plants have seeds that stick to clothing and animal fur.

Disturbed soil is an invitation for invasive plants to take over. Disruption exposes seeds in the seed bank (an accumulation of viable seeds stored in the soil) to sunlight causing germination. Invasive plant species often outcompete any native species seeds that germinate.

Allelopathic plants such as garlic mustard (Alliaria petiolata) release biochemicals in the soil that inhibit the growth and survival of surrounding plants.

Year-round foliage offering privacy and ornamental interest spurs the distribution of many invasive species. Laws are increasingly in place to ban their sale.

Don't purchase, share, or plant invasive plant species

Sadly, many invasive species are still widely propagated and sold in wholesale and retail nurseries. In a 2021 study, Evelyn M. Beaury and colleagues analyzed the U.S. plant trade and found that 60% of the invasive plant species in the United States were still available for purchase! Even worse, 50% of the species that states have identified as especially problematic and 20% of federally identified noxious weeds were still offered for sale! After purchasing some native plants, I was excited when a seedling came up in a pot along with one of my new plants. I nursed it along, eager about the possibility of a new native. When it was large enough to identify, I snapped a photo, used my plant ID app, and identified it as common buckthorn (Rhamnus cathartica), an extremely invasive plant that is not common where I live . . . at least not yet!

Many invasive plants are still available for purchase!

Learning to identify which common ornamental plants are invasive will help you to avoid inadvertently planting these invasive plants in your landscape. By not buying invasive plants that are still being offered in retail nurseries, you will help send the strong message that wholesale growers need to hear:

PLEASE STOP PROPAGATING INVASIVE PLANT SPECIES!

Note the locations of invasive plants growing on your property

Although transitioning our landscapes to 100% native plants is ideal, a more realistic initial goal for most of us is to strive for mostly native plants growing alongside introduced plants that are not invasive. In a multi-year study comparing chickadee nesting success in residential landscapes with varying percentages of introduced versus native plants, Desiree Narango, Douglas Tallamy, and Peter Marra (2017) found that as the percent of native plants increased in the landscape, the probability that chickadees would nest increased. Among those that nested, the number of eggs laid increased, and the likelihood of the nestlings surviving also increased. What an incentive this provides for removing introduced plants, especially invasive ones, to make room for native plants!

You may already recognize some of the invasive plant species growing on your property. As you transition to native plants, your landscape will fall somewhere along the continuum above. Use the tools and resources described in this action and those in the next action to help you identify any plants that are unfamiliar. Are there any pesty invasive plants growing on your property?

Walk around your property and note the locations of invasive plants that need removal. If you drew a map of your property earlier, you could use a copy of that. A rough sketch of the shape of your property is all that's needed. You can draw a plan freehand on a blank grid (see pages 8.2 or 15.2), trace your property from real estate documents, or use Google Earth to zoom in and trace it from the computer screen. Save time by assigning identifying letters or symbols to plant names.

Consider also noting the non-invasive introduced plants growing on your property that could be removed to free up space for native plants that provide more ecological services. Once you've reviewed your property, make an estimate as to where your property currently falls on the continuum above.

Learn to identify invasive plant species so that you can help eradicate them

In this guide, we focus on easy-to-identify invasive plants that you are likely to find in your yard. The more you can learn about the invasive plants in your region, the better prepared you will be to eradicate them from your wildlife habitat. Invasive plants in your landscape come from two primary sources:

Familiarizing yourself with as many invasive species as possible will allow you to spot a new invasive plant before it takes root and sets seed. Since many invasive plants are sold in retail locations nationwide, their distribution is expanding. It's a good idea to become familiar with the top invasive plants across the United States, even those that are not in your area . . . yet!

Online resources to help you identify and learn about invasive plant species

When you come across an unfamiliar plant, it's super important to identify it before allowing it to grow or yanking it out. Although in the early stages of building your wildlife habitat, the plant is likely to be an invasive species, just maybe, it will be a native plant brought in by animals or the wind. Luckily, with an increasing selection of handy plant identification resources available, you no longer need to be an expert botanist to identify most plants. To help you identify the plants you discover growing on your property, we'll first review some popular plant identification apps, then we'll look at several websites including:

National Invasive Species Information Center (NISIC)
EDDMapS (Early Detection and Distribution Mapping System)
Invasive Plant Atlas of the United States (Invasive.org)

As you explore these resources, you will notice that they share each other’s links. In fact, EDDMapS and the Invasive Plant Atlas are both coordinated by the University of Georgia Center for Invasive Species and Ecosystem Health. The sites have handy links for navigating between these different resources.

Amur honeysuckle (Lonicera maackii) is one of the most invasive bush honeysuckles in the Pacific Northwest and Eastern United States. It is rapidly spread by birds (for a photo of its berries, see page 4.5).

Use plant identification apps to identify invasive plant species

First, we'll look briefly at some general plant identification apps that are useful for identifying invasive plants and which later will be useful for identifying native plants. Then, we'll explore several websites designed specifically to help identify and report invasive species.

Invasive plant identification apps

Some apps are designed specifically to help you identify and report invasive species such as the mobile version of the EDDMapS website that we discuss on pages 4.12 - 4.13. The National Invasive Species Information Center (NISIC) that we discuss next (see pages 4.10 - 4.11) is a go-to resource for finding descriptions and links for smartphone apps related to the identification and reporting of invasive species identification. Search online for nisic smartphone apps.

Keep in mind that accurate identification depends on the size of an app’s database of plants. Also, you will find that many of the general plant identification apps are geared toward non-native, ornamental species. Next, we'll explain how to efficiently use several websites that are very helpful for identifying, learning about, and in some cases, reporting invasive species. In this guide, we focus on invasive plants but some of these sites also provide fascinating information about invasive microorganisms, insects, fish, amphibians, reptiles, mammals, and other invasive species.

Use the National Invasive Species Information Center (NISIC) to learn about the most problematic invasive species

The National Invasive Species Information Center (NISIC) site is an ideal place to get to know the worst of the invasive plant bullies. In addition to thorough descriptions, distribution maps are presented for each plant. The limited number of plant profiles* features some of the most problematic invasive species in the United States. (*For a comprehensive list of invasive plant species, visit the Invasive Plant Atlas (Invasive.org) described later in this chapter.) Especially nice are the informative videos about each plant. If you identify one of these species on your property, use the various resources in this action to determine the best method for removing it ASAP!

First, let's look at using the NISIC to learn about an invasive plant species; then, we'll explore its extensive resources.

Use the National Invasive Species Information Center (NISIC) to learn about the most problematic invasive species, continued

Use EDDMapS to view the distribution of invasive species in your region

Take some time to explore the EDDMapS website to discover a wide variety of resources about invasives, including distribution maps of invasive plants, insects, fungi, diseases, and other wildlife. Information, images, and references are provided for each species.

Control of the extremely invasive tree of heaven (Ailanthus altissima; right) is complicated by its similarity in appearance to ecologically beneficial native plants such as sumac (Rhus).

Developed by the University of Georgia and the National Park Service along with other environmental organizations, the Invasive Plant Atlas of the United States (invasiveplantatlas.org) helps users with identification, early detection, prevention, and management of invasive plants by providing species information, images, interactive distribution maps, and early detection reporting procedures. The list of plants included is exhaustive, making this an invaluable resource not only for learning about common invasive species, but also for finding critical information about less common but problematic invasives. Japanese knotweed (Reynoutria japonica aka Fallopia japonica) is one of the most difficult invasive plants to eradicate.

Remove invasives—NOW is the time to start removing invasive plants from your property!

Most large-scale efforts in public and private wildlands rely on herbicides to remove invasive plants. This action guide strongly advocates against using toxic herbicides. Because of the smaller scale of a typical yard, a chemical-free approach is possible by implementing strategic management practices and thoughtful landscape design. While establishing your wildlife habitat, the pressure from invasives will be greater. However, with time, there will be fewer and fewer invasives producing seed. Instead, the native plants will be crowding out the seedlings of invasives that do sprout and building up a native species seed bank.

How to safely dispose of removed invasive plants

Once you've done the hard work of removing invasive plants, care must be taken to prevent accidentally spreading the plant during disposal. Get to know your invasive plants and how they spread—many plants regrow from cut pieces of root, and seeds may ripen even after removal. Some municipalities consider invasive plant species to be controlled waste. Check the policies for your waste collection service and follow their guidelines for disposal.

Many invasive plants can simply be placed in a shallow pile on pavement, a tarp, or a pallet until they dry out and die within a couple of weeks (see page 7.9) Then, the plant waste can be placed in a hidden pile to decompose and monitored in case of regrowth. But some invasive plants require strict precautions; for example, Japanese knotweed and some honeysuckles will regrow from tiny fragments of stems or roots. For tough invasives like these and for plants that have already gone to seed, remove any plant parts that may grow or sprout, such as rhizomatous roots, mature flowers, seeds, and fruits; and seal them in a plastic bag. Place the bag in the sun to bake for at least 3 weeks, longer in cooler seasons. After "baking" the waste in a bag or on hot pavement, place it in a hidden, isolated pile used only for invasive plant waste. Over time, the bottom layers of the pile will decompose into rich organic matter, but due to the potential presence of viable seed, this waste is best left in a pile and monitored. Subsequent layers of newly removed invasive plants and/or cardboard laid over the pile will help to smother any regrowth.

More strategies to effectively remove and keep out invasive plants

The strategies we just discussed for deciding which invasives to tackle first are also the most important strategies for efficient invasive plant management, so they top the list here and bear repeating:

Remove the most problematic invasive species first.
Remove invasive plants BEFORE they go to seed!
Remove small, isolated patches of invasive plants before tackling large patches. Now, let's look at some more strategies

Remove Invasive Plants