Invasive Plants

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Background Information

Ch 273, Criteria for Listing Invasive Terrestrial Plants (DOC) describes the criteria a plant species must meet to be considered invasive and establishes three lists of plants that regulate the sale of invasive plants in the horticulture trade.

The invasive plant lists described in Ch 273 are maintained by the Maine Department of Agriculture, Horticulture Program and include:

  • Do Not Sell Invasive Plant List: The Do Not Sell List is also sometimes referred to as the Prohibited Plant List or the Banned Plant List. It is illegal to import, export, buy, sell or intentionally propagate for sale the species listed on the Do Not Sell Plant List.
  • Watch List of Invasive Plants: Plants on the Watch List have been evaluated using the same criteria as the plants on the Do Not Sell List and while they meet some of the invasive plant criteria, the evidence is insufficient to add the plants to the Do Not Sell List at this time. The Watch List is intended to guide the evaluation process the next time the Invasive Plant Rule is reviewed. The plants on the Watch List may continue to be sold.
  • Invasive Species of Special Concern: These species can be sold, but must have a sign or label indicating that the plants may be invasive in some habitats and alternative plants should be considered.

There are other invasive plant lists in Maine. While this may be confusing, each list serves a separate purpose. Invasive plant lists maintained by other programs and departments serve both regulatory and non-regulatory purposes.

  • Advisory List of Invasive Plants: This list is maintained by the Maine Natural Areas Program in the Department of Agriculture, Conservation and Forestry. The Advisory List is NOT regulatory and is intended for education, outreach, land-management and other non-regulatory uses. Species on The Advisory List may be sold unless they are also listed on the Do Not Sell Plant List or the Invasive Aquatic Plant List.
  • Invasive Aquatic Plant List: This list is maintained by the Invasive Aquatic Species Program in the Department of Environmental Protection. The Invasive Aquatic Plant List is a regulatory list of invasive aquatic plants that can not be introduced, propagated or sold in Maine.

Questions?: Call Gary Fish 207-287-7545 or email gary.fish@maine.gov

Do Not Sell Plant List

The invasive plants listed below are illegal to import, export, buy, sell or intentionally propagate for sale or distribution in Maine. The ban includes all cultivars, varieties and hybrids of these plants.

Species on this list may no longer be sold after the effective date.

Species links go to fact sheets that help with identifcation and control.

Scientific Name Common Name Effective Date
Acer ginnala Amur maple January 1, 2018
Acer platanoides Norway Maple January 1, 2018
Aegopodium podagraria Bishop's Weed January 1, 2018
Ailanthus altissima Tree of Heaven January 1, 2018
Alliaria petiolata Garlic Mustard January 1, 2018
Amorpha fruticosa False Indigo January 1, 2018
Ampelopsis glandulosa Porcelainberry January 1, 2018
Artemisia vulgaris Common Mugwort January 1, 2018
Berberis thunbergii Japanese Barberry January 1, 2018
Berberis vulgaris Common Barberry January 1, 2018
Celastrus orbiculatus Asiatic Bittersweet January 1, 2018
Elaeagnus umbellata Autumn Olive January 1, 2018
Euonymus alatus Winged Euonymus January 1, 2018
Euphorbia cyparissias Cypress Spurge January 1, 2018
Fallopia baldschuanica Chinese Bindweed January 1, 2018
Fallopia japonica Japanese Knotweed January 1, 2018
Frangula alnus Glossy Buckthorn January 1, 2018
Hesperis matronalis Dame's Rocket January 1, 2018
Impatiens glandulifera Ornamental Jewelweed January 1, 2018
Iris pseudacorus Yellow Iris January 1, 2018
Ligustrum vulgare Common Privet January 1, 2018
Lonicera japonica Japanese Honeysuckle January 1, 2018
Lonicera maackii Amur or Bush Honeysuckle January 1, 2018
Lonicera morrowii Morrow's Honeysuckle January 1, 2018
Lonicera tatarica Tatarian Honeysuckle January 1, 2018
Lythrum salicaria Purple Loosestrife January 1, 2018
Microstegium vimineum Stilt Grass January 1, 2018
Paulownia tomentosa Paulownia January 1, 2018
Persicaria perfoliata Mile-a-Minute Weed January 1, 2018
Phellodendron amurense Amur Cork Tree January 1, 2018
Populus alba White Cottonwood January 1, 2018
Robinia pseudoacacia Black Locust January 1, 2018
Rosa multiflora Multiflora Rose January 1, 2018
Alnus glutinosa European alder January 1, 2024
Angelica sylvestris Woodland angelica January 1, 2024
Anthriscus sylvestris wild chervil, raven's wing January 1, 2024
Aralia elata Japanese angelica tree January 1, 2024
Butomus umbellatus Flowering rush January 1, 2024
Elaeagnus angustifolia Russian olive January 1, 2024
Euonymus fortunei Wintercreeper, climbing spindle tree January 1, 2024
Festuca filiformis Fine-leaved sheep fescue January 1, 2024
Ficaria verna Lesser celandine January 1, 2024
Glaucium flavum Yellow hornpoppy January 1, 2024
Glechoma hederacea Ground ivy, creeping Charlie January 1, 2024
Glyceria maxima Great mannagrass, reed mannagrass January 1, 2024
Hippophae rhamnoides Sea buckthorn January 1, 2024
Ligustrum obtusifolium Border privet January 1, 2024
Lonicera xylosteum Dwarf honeysuckle January 1, 2024
Lythrum virgatum European wand loosestrife January 1, 2024
Miscanthus sacchariflorus Amur silvergrass January 1, 2024
Petasites japonicus Fuki, butterbur, giant butterbur January 1, 2024
Phalaris arundinacea Reed canary grass, variegated ribbon grass January 1, 2024
Photinia villosa Photinia, christmas berry January 1, 2024
Phragmites australis Common reed January 1, 2024
Phyllostachys aurea Golden bamboo January 1, 2024
Phyllostachys aureosulcata Yellow groove bamboo January 1, 2024
Pyrus calleryana Callery ("Bradford") pear January 1, 2024
Ranunculus repens Creeping buttercup January 1, 2024
Rubus phoenicolasius Wineberry January 1, 2024
Silphium perfoliatum Cup plant January 1, 2024
Sorbus aucuparia European mountain-ash January 1, 2024
Tussilago farfara Coltsfoot January 1, 2024
Valeriana officinalis Common valerian January 1, 2024

Invasive Species of Special Concern

These species may be sold, but require special labeling or signage.

Rosa rugosa is currently the only species in this category. Starting January 1, 2024 plant sellers will have to display these plants with either a label or a sign that meets the specifications in Chapter 273.

We are currently putting together examples, templates and more guidance on acceptable signs and labels. Until those tools are ready the requirements as listed in the rule are below.

Label specifications:

  • Each plant or container holding the plant must be labeled.
  • Labels must be easily visible to shoppers.
  • The label must contain the words "Invasive Species - Harmful to the Environment" in 14 point bold font.
  • Labels must include non-invasive alternatives and provide instructions for preventing the spread of the labeled plant.
  • Labels must be approved by the Department of Agriculture, Conservation and Forestry.

Sign specifications:

  • Signs must be easily visible to shoppers
  • Signs must be posted at 6 foot intervals around the block of plants
  • Signs must be 8.5 inches wide by 11 inches tall
  • Signs should be weather resistant and must be posted and readable as long as plants are offered for sale.
  • Signs must have a light background with dark bold letters
  • Lettering should be no smaller than 40 point Arial (or similar) font.
  • Signs must include the words "Invasive Species - Harmful to the Environment" and "Ask about alternative plants" and "Follow species specific instructions provided by the vendor"

Invasive Plant Watch List

The Watch List is intended to guide the evaluation process the next time the Invasive Plant Rule is reviewed. These plants were evaluated using the same criteria as the plants on the Do Not Sell list, but at the time of evaluation there was insufficient evidence to support adding these species to the Do Not Sell List.

The plants on the Watch List may be sold with no restrictions.

Scientific Name Common Name
Actinidia arguta Hardy kiwi
Akebia quinata Chocolate vine; five-leaf akebia
Arum italicum Italian arum
Broussonetia papyrifera Paper mulberry
Buddleja davidii Butterfly bush
Clematis terniflora Yam-leaved virgin’s bower, sweet autumn
Dioscorea oppositifolia Indian yam
Dioscorea polystachya Chinese yam
Eragrostis curvula Weeping lovegrass
Filipendula ulmaria Queen of the meadow
Lespedeza bicolor Bicolor lespedeza, two-colored bush-clover
Ligustrum ovalifolium California privet
Lonicera caerulea Honeyberry, haskap
Lychnis flos-cuculi or Silene flos-cuculi Ragged robin
Morus alba White mulberry
Quercus acutissima Sawtooth oak
Rosa rugosa Rugosa rose, beach rose
Saccharum ravennae or Tripidium ravennae Ravenna grass, hardy pampas grass
Salvia glutinosa Sticky sage
Silybum marianum Milk thistle
Spiraea japonica Japanese spiraea
Symplocos paniculata Sapphire-berry
Syringa reticulata Japanese tree lilac
Toona sinensis Chinese cedar
Ulmus pumila Siberian elm
Viburnum dilatatum Linden arrowwood
Viburnum sieboldii Siebold viburnum
Wisteria floribunda Japanese wisteria
Wisteria sinensis Chinese wisteria

Alternatives to Invasive Plants

What are invasive plants?

The Invasive Plant rule lists specific criteria that a plant must meet in order to be considered invasive. The species must:

  • be non-native,
  • rapidly grow, establish and spread in minimally managed habitats,
  • have the biological potential to spread widely including across spatial gaps (unassisted by people),
  • exist in high numbers or large colonies in minimally managed habitats and
  • displace native species in minimally managed habitats.

Updating the Do Not Sell Plant List

Chapter 273, Criteria for Listing Invasive Terrestrial Plants prescribes a five-year review of the species listed on the Do Not Sell Plant List. The last review of Chapter 273 was completed in 2022.

To review the list the Horticulture Program assembles a stakeholder committee comprised of a variety of individuals from industry, government, non-profit and educational institutions that represent different organizations affected by the development, implementation and enforcement of the prohibited plant list. With input from the stakeholder committee the Department evaluates species using the invasive plant criteria described in Chapter 273 and proposes changes to the Do Not Sell List.

Opportunities for Public Participation

In addition to the formal rule review that happens every 5 years, anyone can request review of a specific species at any time.