UNIVERSITY PARK, Pa. — Removing invasive shrubs to restore native forest habitat brings a surprising result, according to Penn State researchers, who say desired native understory plants display an unexpected ability and vigor to recolonize open spots.
St. Louis Community College-Meramec takes action to remove an aggressive, exotic vine that is invading St. Louis and Missouri.
The sycamore tree was so smothered by a dense vine that its white trunk appeared green. The campus of St. Louis Community College-Meramec (STLCC) had been invaded by Euonymus fortunei ‘Coloratus’ (commonly known as wintercreeper euonymus or Climbing Euonymus), and if the facilities department didn’t do something soon, the problem would get worse. They tasked groundskeeper Alan Cain to liberate the sycamore and 32 other trees.
“This will be an ongoing effort as we work to remove the Euonymus fortunei on the campus,” says Kelly Crandall, building and grounds supervisor for the campus. “Hopefully we will be able to remove individual plants as we recognize them once we have established control.”
How did this plant become such a problem? According to a fact sheet developed by the Missouri Department of Conservation, wintercreeper euonymus—a broadleaf semi-evergreen creeping vine—“was chosen for cultivation because it grows rapidly, even under harsh conditions. Found in a variety of habitats, wintercreeper euonymus can tolerate full sun, heavy shade and moist soil conditions.”
It establishes easily in disturbed or neglected soil, so many places where humans have altered the landscape are prime ground for wintercreeper colonies. The vine’s aggressive growth robs native plants of their chance to grow, preventing them from being vital food and nectar sources for beneficial wildlife such as pollinating insects.
Wintercreeper euonymus has been a mainstay non-native horticultural ground cover used for many years, to cover, as a turf alternative, landscape areas with poor soils, soil moisture limitations, and challenging exposure extremes, including extreme deep shade. As a horizontal ground cover, wintercreeper euonymus bears no fruit/seed, but its vertical vining form produces copious volumes of fruit that is favored by birds. Birds ultimately spread the seeds to landscape and garden areas where wintercreeper euonymus may not be intended nor desired and considered a weedy pest. Once established, wintercreeper euonymus can dominate the woodland floor, thus eliminating a diversity of wildflowers and other understory plants.
Beyond the ground level impact, the vertical vining growth of wintercreeper euonymus can impose structural damage, potentially inflicting death to trees and shrubs.
A statewide assessment organized by the Missouri Invasive Plant Task Force (MoIP) found wintercreeper euonymus expanding its range at a moderate increase around St. Louis and causing moderate to severe environmental degradation in all regions of the state where data were reported. The abundance of escaped populations is particularly high the ecoregion that includes St. Louis. More than two dozen field experts assessed 142 invasive species for this assessment. The data were released in early 2019.
An inter-agency and inter-organizational resource of the Missouri Prairie Foundation’s Grow Native! program, MoIP has the principal goal of making early detection and control of invasive plants a higher statewide priority. The MoIP website offers resources on how to control highly invasive species such as wintercreeper. “In addition to encouraging landowners to keep invasive species from spreading,” said Carol Davit, Executive Director of the Missouri Prairie Foundation, the nonprofit land trust that runs the Grow Native! Program and MoIP, “We also want to teach people how to plant beneficial native species in place of invasive plants.”
Alternative native, ground covers include golden groundsel (Packera obovatus) wild strawberry (Fragaria virginiana), three-leaved stonecrop (Sedum ternatum), wild ginger (Asarum canadense), calamint (Clinopodium arkansanum) and pussytoes (Antennaria parlinii). This web page from the Missouri Botanical Garden offers photos of native plants for comparison, as well as links to instructions on how to manage invasive plants on your property. The Grow Native! Native Plant Database offers hundreds of native plants with customizable search options to choose other alternatives.
Wintercreeper euonymus can be identified by its dense groundcover up to three feet in height. Its thick, glossy leaves are oval-shaped, no more than 1 inch in length, and easily identifiable by silvery white veins. Smooth, pinkish fruits mature in the fall.
“Since the vertical growth of this highly aggressive ground cover produces the seed producing fruit responsible for unintended landscape invasion, STLCC’s removal efforts are a valuable asset for both the campus grounds and the surrounding residential neighborhoods,” says Bill Ruppert, Kirkwood resident who spearheaded the establishment of MoIP. The grounds staff began cutting vertical vines June 2019. In most cases, the vines are cut, treated and left on the tree to fall off on their own accord thereby eliminating bark damage. The staff completed the initial cutting and removal in July and will return after the first freeze this winter to remove or recut and treat vine stumps. (For details on how to treat cut stumps with herbicide, visit moinvasives.org.)
“I think this action demonstrates that STLCC is a responsible college that is concerned with the spread of invasive plants in the community,” says Jerry Pence, Program Coordinator/Assistant Professor in the horticulture department at STLCC-Meramec.
MoIP’s website offers guidelines on how to manage invasive plants.. For information on landscape services, including professionals specializing in removal of invasive plants, and who sell native plants and seed, please visit grownative.org.
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About the Missouri Invasive Plant Task Force
The Missouri Invasive Plant Task Force (MoIP) is a resource of Grow Native!—a 19-year-old native plant marketing and education program serving the lower Midwest. Grow Native! is administratively housed by the nonprofit Missouri Prairie Foundation. For more information about MoIP, visit www.moinvasives.org, email [email protected] or call 417-299-1794; for more on the Grow Native! program at grownative.org or for more on the Missouri Prairie Foundation visit moprairie.org.
About St. Louis Community College
Established in 1962, St. Louis Community College is the largest community college district in Missouri and one of the largest in the United States. STLCC has four campuses: Florissant Valley, Forest Park, Meramec and Wildwood. The College annually serves more than 50,000 students through credit courses, continuing education, and workforce development programs. For more information about STLCC, visit stlcc.edu
Do your part to reduce this highly invasive tree that threatens native wildlife and causes difficulties for private and public landowners, and receive a free native tree!
Jefferson City, MO (April 15, 2019)—Homeowners with an invasive tree in their yard can celebrate Arbor Day in a special way this year: by cutting it down.
To spread awareness about how the invasive Callery pear causes harm to economics and environment, MoIP will partner with Forest ReLeaf and Forrest Keeling Nursery for a Callery Pear “Buy-back” offering on April 26. People who supply photos of themselves with a cut-down, in-bloom Callery pear tree in their yards will receive a free native tree to replace it. The offer is limited to one native tree per photo proof of cut-down tree. Participants are invited to pick up their trees at Forest Releaf CommuniTree Gardens Nursery, located in Creve Coeur Park (2194 Creve Coeur Mill Rd SOUTH, from Hwy 141/Maryland Heights Expressway) from 9 a.m. to 4 p.m., while supplies last.
“People once planted Callery pear trees for the beauty of their spring blossoms,” says Carol Davit, director of Missouri Prairie Foundation (MPF) and chair of the Missouri Invasive Plant Task Force (MoIP). “We now understand that when non-native Callery pear cultivars cross pollinate, the hybrid offspring become invasive, and are already causing harm to properties across the state.”
An inter-agency and inter-organizational resource of MPF’s Grow Native! program, MoIP’s principal goal is to make early detection and control of invasive plants a higher statewide priority. The MoIP website offers resources on how to control highly invasive species; and provides resources on native alternative trees to plant instead of Callery pear. “We don’t want to merely encourage landowners to keep invasive species from spreading; we want to teach people how to plant beneficial native species in place of invasive plants,” Davit says. “We are excited to partner with Forest ReLeaf, whose mission is to restore and sustain urban forests by planting trees and enriching communities.”
Native, noninvasive trees with white flowers blooming in April include serviceberry, wild plum, and dogwoods. This web page from the City of Columbia offers photos of native trees for comparison.
Callery pear (Pyrus calleryana) is native to China. Several cultivars of the tree are offered commercially, including ‘Aristocrat’, ‘Autumn Blaze’, ‘Bradford’ (which is the commonly planted “Bradford pear”), ‘Capital’, ‘Cleveland,’ ‘Chanticleer’, ‘Redspire’, and ‘Whitehouse’.
Callery pear limbs generally grow vertically, forming a pyramid or egg shape. In early April, very dense clusters of white flowers cover the tree before leaves form. In maturity, they reach heights of 30 to 40 feet. Property owners are encouraged to cut the trees during spring (when they are easy to identify) as a means to reducing populations from spreading in unwanted areas. (For details on how to treat cut stumps with herbicide, visit MoIP’s management page.)
These cultivars are generally themselves unable to produce fertile seeds when self-pollinated, or cross-pollinated with another tree of the same cultivar. However, if different cultivars of Callery pears are grown in proximity (for instance, neighboring homes or strip malls), thanks to insect pollination, they often produce fertile seeds—carried by birds—that can sprout and establish wherever they are dispersed. Each year, older trees in urban landscapes produce viable seeds that contribute to growing infestations. Breaking this cycle begins with choosing native alternatives for future plantings, and controlling existing invasive populations.
Participants in the “Buy-back” will have the opportunity to receive one of the following trees native to Missouri: Bur Oak, Northern Red Oak, Shumard Oak, Roughleaf Dogwood, Buttonbush, and hackberry. Four hundred trees are available, each in 3-gallon containers and between 4 and 5 feet tall.
Availability is on a first-come, first-served basis and may go fast; call ahead to 417-299-1794 or 314-956-2561 to confirm availability. To be eligible for a free tree, participants must either bring a photo of themselves next to their cut-down Callery pear or email the photo ahead of time to [email protected]
Frequently Asked Questions
Q: I cut down my callery pear in the last year–can I still get a native tree to replace it?
A: Rules still apply: bring or email a photo of the downed tree or cut stump, preferably with you in it. Tree availability is on a first-come, first-served basis .
Q: I don’t have a chainsaw. Where can I get help having my Callery pear professionally removed?
A: Please refer to the Grow Native! Resource Guide listings for Arborists and Land Care & Landscape Services to find professionals in your area who can assist with tree removal. These companies are on board with the Grow Native! mission to protect and restore biodiversity.
Q: Can I have a voucher to pick up my tree?
A: If you email [email protected] ahead of time, we will log your photos, but we unfortunately are not equipped to keep track of orders ahead of time. Trees will be available on a first-come, first-served basis from 9 a.m. – 4 p.m. on April 26, 2019. We have 500 native trees available, but they may go fast; you may call ahead day-of to 417-299-1794 or 314-956-2561 to confirm availability.
Q: I have 2 “Cleveland” Pear trees, would they be eligible?
A: Yes, absolutely, Cleveland Select is one of 26 cultivars of the Callery pear!
Q: I cannot transport a tree to Forest ReLeaf.
A: We’re not asking that people bring in a Callery pear tree itself – a simple photo of yourself with one cut on your property will do!
Q: I live too far from St. Louis to make the trade worth it. Are any other cities doing a Buy-back?
Our hope is that the St. Louis Callery pear Buy-back is a smashing success so we can make a case for taking the program to other parts of the state in 2020.
However, the event in St. Louis is our only pilot location for the Buy-back model.
As a task force, we are working to get invasive plants in more conversations. Our task force chair maintains a good relationship with the Missouri Municipal League, and she will present on the Buy-back and other MoIP projects at their upcoming conference in September. We also have many members and stakeholders tasked with sharing our information in their parts of the state.
Q: I wish Missouri’s county governments and the state would cut down their invasive pear trees on road sides and government land. They are contributing more than a homeowner with 1 tree. We all need to be part of the fight to support native trees.
A: Great point! We are working to get invasive plants in more conversations and out of more land–private and public alike.
As we explore ways to have an impact statewide, a common answer from government entities is that they need to hear from more citizens themselves who are concerned with issues such as invasive plants on public land. Any advocacy you and people in your circle can do will go far.
And there is a lot of good news! For instance, in 2018 Missouri State Parks released a comprehensive invasive species management plan for each of their parks. The Army Corps of Engineers is doing a lot of invasive plant work, as is Mark Twain National Forest. That’s only naming a few.
In fact, we are compiling a web page highlighting the commitments and work different state agencies are doing to address invasive plants. We hope to have this online before our next quarterly meeting July 9, 2019. Stay tuned, and thanks for your interest!
Q: I want to remove Callery pear from my property. What is the best way to ensure it does not grow back?
A: Please see Effective Control of Callery Pear – instructions by Dr. Reid Smeda, MU Extension, for the Missouri Invasive Plant Task Force
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The Missouri Invasive Plant Task Force (MoIP) is a resource of Grow Native!—a 19-year-old native plant marketing and education program serving the lower Midwest. Grow Native! is administratively housed by the nonprofit Missouri Prairie Foundation. For more information about MoIP, visit www.moinvasives.org, email info or call 417-299-1794; for more on the Grow Native! program at grownative.org or for more on the Missouri Prairie Foundation visit moprairie.org.
Forest ReLeaf of Missouri is an independent, nonprofit organization dedicated to inspiring volunteer efforts in planting and caring for our trees and forests, particularly those in our cities and towns. Since 1993, the organization has provided over 200,000 native trees for plantings throughout the region. www.moreleaf.org
Emmenegger Nature Park is a 110-acre wooded park in Kirkwood, Missouri, located on the Meramec River and endowed with unusual natural beauty and biological diversity.As an “adopt-a-park” subset of Kirkwood Parks Assistance Corps (KPAC), a small crew of regular volunteers has been removing honeysuckle at Emmenegger for 4-5 years. We have worked every Sunday, March through May, and September through November. Two of our crew also work there during the week throughout the seasons.Upon occasion we have been joined by students from Kirkwood High School and Meramec Community College, and volunteer participants with Biodiversity St. Louis “Honeysuckle Sweep Week.”It would be impossible to know how many honeysuckle shrubs we’ve removed, but like most natural areas in the St. Louis region, the park was heavily infested. An estimate from Kirkwood Parks Department is that we’ve cleared about a third of the park, as many as 30 acres.We also remove euonymus, garlic mustard, Callery Pear, Burning Bush, Japanese Beefsteak Plant and other known exotic invasives.