Creeping In: 2024’s States Most At Risk for Invasive Plant Species

Two women smile while removing invasive plants from a natural area

All U.S. states deal with invasive plants, but which states have the most species to identify and combat? 

To find out, Lawn Love ranked 2024’s States With the Most Invasive Plant Species.

We compared the 50 states and the District of Columbia based on 3 categories. It can be challenging to pinpoint exactly how many invasive species impact an area, so we considered the number of invasive species per state according to the USDA’s National Invasive Species Information Center (NISIC) and invasive species reports from the University of Georgia (UGA). 

For example, Connecticut’s ranking at 4th place indicates it is one of the states most impacted by invasive plant species per our sources, based on these factors. 

We also considered environmental characteristics, among 5 total metrics.

Explore our ranking below. To learn how we ranked the states, see our methodology.

Note: We’ve updated our title from “Creeping In: 2024’s States With the Most Invasive Plant Species” to “Creeping In: States Most At Risk for Invasive Plant Species” to better reflect our methodology. The new title emphasizes the factors considered, including invasive plant presence, climate, and regulatory membership, to rank the states most at risk for invasive species impact. 

In this article

State rankings

See how each state fared in our ranking:

Top 5 close up

Check out the slideshow below for highlights on each of our 5 most invaded states.

A scenic roadway along the Blue Ridge Mountains in North Carolina
No. 5: North Carolina | Overall score: 63.95

Number of Invasive Plant Species (NISIC): 53 | Rank: 1
Number of Invasive Plant Species Reported (UGA): 738 | Rank: 12
Percentage of Sunshine: 60.39% | Rank: 19
Average Monthly Inches of Precipitation: 4.041 | Rank: 8
National Association of Exotic Pest Plant Councils Membership: 1 (Yes) Rank: 20

Local tips: 
9 Best Native Plants for Raleigh
11 Best Native Plants for Durham-Chapel Hill

Photo credit: Jason Schronce | Adobe Stock | License
Wildflowers bloom along Diamond Valley Lake in California
No. 1: California | Overall score: 71.39

Number of Invasive Plant Species (NISIC): 48 | Rank: 7
Number of Invasive Plant Species Reported (UGA): 1,695 | Rank: 1
Percentage of Sunshine: 72.5% | Rank: 4
Average Monthly Inches of Precipitation: 1.63 | Rank: 42
National Association of Exotic Pest Plant Councils Membership: 1 (Yes) | Rank: 20

Local tips: Invasive plants can worsen wildfire conditions, so you may want to consider native species and fire-resistant landscaping when revamping your Golden State lawn.

27 California Native Plants
The Best Native Plants for Your Bay Area Landscape
10 Best Native Plants for San Diego
9 Best Native Plants for Sacramento

Photo credit: Kit Leong | Adobe Stock | License
People gather along the pond in Central Park in New York City
No. 2: New York | Overall score: 70.54

Number of Invasive Plant Species (NISIC): 50 | Rank: 4
Number of Invasive Plant Species Reported (UGA): 935 | Rank: 3
Percentage of Sunshine: 48.86% | Rank: 47
Average Monthly Inches of Precipitation: 3.48 | Rank: 23
National Association of Exotic Pest Plant Councils Membership: 0 (No) | Rank: 1

Local tips: 
10 Best Native Plants for Albany
New York Invasive Species Regulations

Photo credit: Alessandro Persiani | Adobe Stock | License
People walk around Boston Common in Massachusetts
No. 3: Massachusetts | Overall score: 67.8

Number of Invasive Plant Species (NISIC): 46 | Rank: 16
Number of Invasive Plant Species Reported (UGA): 821 | Rank: 4
Percentage of Sunshine: 58.83% | Rank: 25
Average Monthly Inches of Precipitation: 4.035 | Rank: 9
National Association of Exotic Pest Plant Councils Membership: 0 (No) | Rank: 1

Local tip: 
Massachusetts Prohibited Plant List

Photo credit: Zack Frank | Adobe Stock | License
The skyline of Hartford, Connecticut, behind a row of trees along the Connecticut River
No. 4: Connecticut | Overall score: 65.87

Number of Invasive Plant Species (NISIC): 47 | Rank: 10
Number of Invasive Plant Species Reported (UGA): 702 | Rank: 18
Percentage of Sunshine: 58% | Rank: 29
Average Monthly Inches of Precipitation: 3.6 | Rank: 17
National Association of Exotic Pest Plant Councils Membership: 0 (No) | Rank: 1

Local tip: 
Connecticut Invasive Plant List

Photo credit: Wangkun Jia | Adobe Stock | License
A scenic roadway along the Blue Ridge Mountains in North Carolina
No. 5: North Carolina | Overall score: 63.95

Number of Invasive Plant Species (NISIC): 53 | Rank: 1
Number of Invasive Plant Species Reported (UGA): 738 | Rank: 12
Percentage of Sunshine: 60.39% | Rank: 19
Average Monthly Inches of Precipitation: 4.041 | Rank: 8
National Association of Exotic Pest Plant Councils Membership: 1 (Yes) Rank: 20

Local tips: 
9 Best Native Plants for Raleigh
11 Best Native Plants for Durham-Chapel Hill

Photo credit: Jason Schronce | Adobe Stock | License
Wildflowers bloom along Diamond Valley Lake in California
No. 1: California | Overall score: 71.39

Number of Invasive Plant Species (NISIC): 48 | Rank: 7
Number of Invasive Plant Species Reported (UGA): 1,695 | Rank: 1
Percentage of Sunshine: 72.5% | Rank: 4
Average Monthly Inches of Precipitation: 1.63 | Rank: 42
National Association of Exotic Pest Plant Councils Membership: 1 (Yes) | Rank: 20

Local tips: Invasive plants can worsen wildfire conditions, so you may want to consider native species and fire-resistant landscaping when revamping your Golden State lawn.

27 California Native Plants
The Best Native Plants for Your Bay Area Landscape
10 Best Native Plants for San Diego
9 Best Native Plants for Sacramento

Photo credit: Kit Leong | Adobe Stock | License

Key insights

North Carolina (No. 5) fights against the highest number of invasive plant species, 53, according to the National Invasive Species Information Center. Virginia (No. 7) and Kentucky (No. 9) follow closely with 52 and 51 invasive species, respectively. 

Not all non-native species are classified as invasive. However, non-native plants can be dormant for hundreds of years before becoming invasive and wreaking havoc on the environment. Most dormant invasive plants take an average of 40 years to become an issue.

According to tracking data from the University of Georgia, 1,695 invasive or non-native plant species have been mapped in the California (No. 1) wilderness, the most in our ranking. Florida (No. 6) follows closely with 1,509 species reported and has also been invaded by numerous animal species. These 2 sunny states also have optimal weather conditions for many species — native or not — to grow and spread. 

Expert take

It can be very difficult to keep invasive plants at bay, especially when they’re for sale at nurseries across the country.

We turned to a panel of plant experts to learn more about non-native and invasive species, and what we can do to stop their spread. Read their insights below.

  1. Are all non-native plant species bad for the environment? Why or why not?
  2. What are 3 of the main benefits of landscaping with native plants?
  3. What are 3 considerations to take before landscaping with non-native plants?
  4. What are 3 misconceptions about invasive plants?
  5. What are 3 invasive plants in the U.S. to watch out for?
  6. What is 1 way people can help stop the spread of invasive plant species in their area?
  7. What, if anything, can local or state governments do to reduce the impact of invasive plants?
Bethany Bradley
Bethany Bradley
Professor of Environmental Conservation

Behind the ranking

First, we determined the factors (metrics) that are most relevant to rank the States With the Most Invasive Plant Species. We then assigned a weight to each factor based on its importance and grouped those factors into 3 categories: Invasive Plant Presence, Climate, and Regulatory Membership. The categories, factors, and their weights are listed in the table below.

For each of the 50 states and the District of Columbia, we then gathered data on each factor from the sources listed below the table. 

Finally, we calculated scores (out of 100 points) for each state to determine its rank in each factor, each category, and overall. A state’s Overall Score is the average of its scores across all factors and categories. The highest Overall Score ranked “Most Invaded” (No. 1) and the lowest “Least Invaded” (No. 50).

Notes:

  • The “Worst” among individual factors may not be No. 50 due to ties.
  • “Number of Invasive Plant Species” includes terrestrial and aquatic plant species listed on the U.S. Department of Agriculture’s National Invasive Species Information Center site. 
  • “Number of Invasive Plant Species Reported” includes invasive and non-native plants mapped by a database of citizen scientists and managed by the University of Georgia Center for Invasive Species and Ecosystem Health. These may include non-native plants that have yet to be classified as invasive and may also include negative and eradicated records.

Sources

National Association of Invasive Plant Councils, National Invasive Species Information Center, National Oceanic and Atmospheric Administration, University of Georgia

Final thoughts: 5 invasive plants to watch out for

Research suggests that invasive species have cost North America an estimated $26 billion or more each year since 2010. 

Invasive species — bugs, plants, and animals included — can contribute to issues like tree cover loss and hog resources from local species, leading to species endangerment and extinction. Meanwhile, planting native species can reduce water bills, preserve local biodiversity, and control erosion. 

Click through our slideshow below to learn more about 5 invasive species that might be right in your backyard. 

Clusters of giant hogweed with little white flowers grow tall in a natural area
Giant hogweed | Heracleum mantegazzianum

If you spot giant hogweed, stay away! This giant invasive herb can surpass 14 feet in height, and contact with its sap can cause severe burns, scarring, and sun sensitivity. This plant can produce between 20,000 and 100,000 seeds, which can survive in the ground for more than 5 years.

Photo credit: Andrew | Wikimedia Commons | CC BY 2.0
Lavender blooms of a Chinese wisteria
Chinese wisteria | Wisteria sinensis

Chinese wisteria is a fragrant and fast-growing vine that can live for more than 50 years. While appealing to the eye with beautiful flowers, this invasive plant is known to cover and kill plants and trees.

Photo credit: Krzysztof Ziarnek, Kenraiz | Wikimedia Commons | CC BY-SA 4.0
Clusters of red seeds line the branches of a Tree-of-Heaven
Tree-of-Heaven | Ailanthus altissima

Tree-of-Heaven is a large and smelly invasive tree that can survive and spread under harsh conditions. The tree produces chemicals with a herbicidal effect, killing neighboring native plants. It also attracts the invasive spotted lanternfly.
 
Photo credit: Cbaile19 | Wikimedia Commons | CC0 1.0
Kudzu vine overtakes a wild area, blanketing trees and the ground
Kudzu | Pueraria lobata

Frequently spotted alongside the road, Kudzu is a wide-spreading invasive vine. Growing up to a foot per day, it can smother forests, agricultural lands, and vacant lots. It is also known to disrupt the railroad and soybean industries.

Photo credit: Scott Ehardt | Wikimedia Commons | Public Domain
English ivy covers an abandoned home
English ivy | Hedera helix

Commonly sold in plant shops, English ivy is a ground cover and vine bearing toxic leaves and fruit. Known to dominate understories and tree canopies, the vine blocks sunlight from reaching other vegetation, killing plants and preventing new growth. 

Photo credit: Forest and Kim Starr | Flickr | CC BY 2.0
Clusters of giant hogweed with little white flowers grow tall in a natural area
Giant hogweed | Heracleum mantegazzianum

If you spot giant hogweed, stay away! This giant invasive herb can surpass 14 feet in height, and contact with its sap can cause severe burns, scarring, and sun sensitivity. This plant can produce between 20,000 and 100,000 seeds, which can survive in the ground for more than 5 years.

Photo credit: Andrew | Wikimedia Commons | CC BY 2.0
Lavender blooms of a Chinese wisteria
Chinese wisteria | Wisteria sinensis

Chinese wisteria is a fragrant and fast-growing vine that can live for more than 50 years. While appealing to the eye with beautiful flowers, this invasive plant is known to cover and kill plants and trees.

Photo credit: Krzysztof Ziarnek, Kenraiz | Wikimedia Commons | CC BY-SA 4.0

Avoid invasive plants and noxious weeds, and hire a local Lawn Love crew to fill your landscape with native plants.

Media resources

Quotes from Lawn Love Editor-in-Chief, Sharon Sullivan

High-resolution images of states

Main photo credit: U.S. Fish and Wildlife Service – Northeast Region | Flickr | Public Domain

Sav Maive

Sav Maive is a writer and director based in San Antonio. Sav is a graduate from the University of Virginia and is a loving cat and plant mom.