Image: Emilio Concari
Vermont’s forests are a vital part of the state’s identity and ecological health. Whether you’re a nursery professional, landscaper, or homeowner, staying informed about plant health requirements is an important step in protecting these shared landscapes—especially when bringing plants, such as eastern hemlocks, into the state.
Eastern hemlocks are native evergreens that provide habitat for wildlife, stabilize soils, and enhance the character of both natural areas and residential spaces. However, they are increasingly at risk from an invasive insect called the Hemlock Woolly Adelgid (HWA). In Vermont, HWA is currently confirmed in the southern counties of Bennington, Windham, and Windsor.
To help prevent the spread of HWA to new areas, Vermont has established a Hemlock Woolly Adelgid quarantine rule that applies to the importation of live hemlocks.
Hemlock Woolly Adelgid (HWA) Quarantine Requirements
If you are sourcing hemlock trees from out of state, specific documentation is required based on the origin of the trees. All incoming hemlock stock must be accompanied by a Phytosanitary Certificate, which can be obtained from the certifying authority in the state of origin. Distribution information of HWA in the U.S. can be found here.
- From areas where HWA is present:
- Trees must be treated for HWA prior to entering Vermont.
- Shipments must include a State Phytosanitary Certificate that verifies the treatment method, treatment date, and the number and type of trees.
- From areas where HWA is not present:
- A Phytosanitary Certificate or Certificate of Origin is required to confirm the origin of the trees and to verify that they were not exposed to HWA during production or transport.
These measures are designed to prevent new introductions of HWA and support the health of Vermont’s forests and ecosystems. The focus is on prevention, which is more effective and less disruptive than managing active infestation.
Image: F.W. Ravlin, Michigan State University
Other Pests to Be Aware Of
Recently, inspectors from the Vermont Agency of Agriculture’s Plant Health Program have observed an increase in hemlock shipments arriving with another introduced invasive insect known as the elongate hemlock scale (EHS). Like HWA, EHS has a limited known distribution in Vermont, and current efforts are focused on slowing its spread.
Careful inspection of incoming shipments and making sure that all the required documentation is in place are simple but pragmatic and effective ways to reduce risk of spread.
General Nursery Stock Requirements
All nursery stock sold, planted, or distributed in Vermont, whether hemlock or not, must be healthy, vigorous, and free from serious pests and plant diseases. This helps protect Vermont’s natural communities and ensures high-quality plants for customers.
Any nursery stock brought into Vermont from another state must be accompanied by a valid certificate of inspection issued by the originating state. This certificate should confirm that the plants have been inspected and are free of serious pests or diseases.
If nursery stock arrives in Vermont with a known pest or disease issue, the Agency will work with the affected business to identify appropriate next steps. This may include treatment, return of the plants, or disposal, depending on the situation.
Staying Informed
If you’re operating a nursery, managing landscapes or gardening at home, taking proactive, informed steps help reduce the risk of introducing an undesirable species through the interstate movement of plants into Vermont. Understanding and following plant health guidelines is an important part of protecting and supporting the long-term health and resiliency of Vermont’s interconnected landscape.
Helpful Resources
Here are some useful links with information about HWA, EHS, and Vermont’s nursery plant health regulations.
Homeowner Gardening Questions
UVM Extension-Master Gardener Program
Hemlock Woolly Adelgid
- Vermont HWA Quarantine Rule (pdf)
- U.S. Distribution of HWA (Maps and Lists)
- VT Department of Forests, Parks and Recreation HWA Info (pdf)
- VT Agency of Natural Resources: Guide to Eastern Hemlock Management
Elongate Hemlock Scale
- VTinvasives.org: EHS
- EHS Fact Sheet-Penn State Extension
- EHS Fact Sheet-UMass Amherst
- EHS Fact Sheet-NC State Extension
General Nursery Related Resources