Bulletin #2518, Best Practices for Plant Sale Donors and Buyers in Maine

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Developed by Tori Jackson, Extension Professor of Agriculture & Natural Resources, Lynne Holland, Community Education Assistant, University of Maine Cooperative Extension, and Naomi Jacobs, Master Gardener Volunteer

Reviewed by Katherine Garland, Horticultural Professional, University of Maine Cooperative Extension and Sarah Scally, Assistant State Horticulturist, Maine Department of Agriculture, Conservation and Forestry

For information about UMaine Extension programs and resources, visit extension.umaine.edu.
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small plants in pots

What passionate gardener hasn’t slammed on the brakes at the sight of a spring plant sale by the side of the road? Sales of donated plants are a major source of income for garden clubs, land trusts and conservation groups, as well as an exciting way for plant lovers to acquire new treasures at a modest cost.

Unfortunately, plants dug from home gardens can transmit problem organisms such as crazy worms (Amynthas agrestis), European fire ants (Myrmica rubra), and winter moths (Operophtera brumata), as well as invasive plants like black swallowwort (Cynanchum louiseae). Several Maine plant sales have been discontinued in recent years due to such concerns. Here are steps you can take to reduce the chance of spreading invasive pests through this beloved spring tradition.

Best Practices for Donors

  • Do not offer any plants the state of Maine has prohibited from being sold due to their invasive nature. Review the Invasive Plant Do Not Sell list prior to every plant sale. Similarly, many plants not listed as invasive are still troublemakers. If a plant tends to take over the garden and is hard to contain, it’s probably best not to share it with others.
  • Use new, sterile soil and sterilized pots to prevent transmission of seeds, disease, and insect pests, which may be present as cocoons, larvae, or adults.
  • Sterilize tools such as trowels and shovels. A 10% chlorine solution works well.
  • Before you propagate, inspect plants carefully to screen out those with any sign of pests or disease.
  • Pot rooted cuttings rather than divisions whenever possible.
  • If you do donate divisions, rinse the roots before potting, and manually remove the roots of invasive plants such as black swallowwort or bindweed.  This is labor-intensive but can be effective if done thoroughly.
  • Work with your group to ensure that all donors follow best practices. Perhaps the group could make bulk purchases of new pots and potting soil, for instance, to reduce the cost to donors.
  • If you live in an area where pests are known to be established, ask your group to discuss whether the sale tradition should be suspended or discontinued.
  • If your inventory seems to be impacted by these pests, consider adding locally grown annual seedlings to the offering. Vegetable seedlings have been successful for some sales in this way.
  • Finally, the earlier the plants are dug up, divided, and potted, the less trauma the plants will experience, and the more happily they can settle into their new homes. Strong, healthy plants are more resistant to disease and less attractive to many insect pests.

Best Practices for Buyers

  • If you live in an area where a pest is known to have taken hold, ask the sellers about whether their donors are required to follow best practices.
  • Inspect plants carefully before buying.
  • Rinse the roots before planting, unless you are confident that sellers have used sterile media and other best practices.
  • Be aware of the invasive plants prohibited for sale in the state of Maine. Some plant sales may unintentionally be offering these items, so it’s important to be an informed buyer.

Best Practices for Organizers

  • Get the word out about your plant sale so that no plant remains an orphan. Social media, local newspapers, and local calendars all have deadlines that vary from a few days to several weeks before an event, so plan ahead.
  • The University of Maine Cooperative Extension maintains a database and map of plant sales. Use this Google Form to put the specifics of your plant sale “on the map.”
  • An organized sales area that leads the buyers in one direction through the sale is not only efficient but also easier to manage, whether your sale is live or presale with pick-up.

Additional Resources

1. Maine Invasive Plants Banned for Sale

The Maine Department of Agriculture, Conservation and Forestry has adopted rules (DOC) that prohibit the sale of 33 invasive plants.

2. Crazy Worm (Amynthas agrestis)

Crazy worms are not yet widespread in Maine, but have been found in Augusta, Portland, Boothbay, and nursery settings since 2014. They damage forest habitats by gobbling up the organic layer and driving out native worms.

3. European Fire Ant (Myrmica rubra)

The European fire ant is established in many areas along Maine’s coast and has been observed as far inland as Bangor. It endangers native ants; the aggressive swarming behavior and nasty stings can render an area unusable by humans.

Bulletin #2551, European Fire Ant: Management for Homeowners

4. Winter Moth (Operophtera brumata)

Winter Moth is found in coastal Maine from Kittery to Bar Harbor. Its cocoons are in the soil from June to November. The voracious larvae defoliate trees and shrubs.

5. Black Swallowwort (Cynanchum louiseae)

Much of Cumberland County has a problem with this severely invasive vine, which can alter bird habitats and choke out native plant species including milkweed, the preferred host of the monarch butterfly. Localized stands are found elsewhere in the state.

Bulletin #2523, Maine Invasive Plants: Black Swallowwort, Cynanchum louiseae (Milkweed Family)

See Maine Natural Areas Program Black Swallowwort.

6. Maine Department of Agriculture, Conservation and Forestry Invasive Plants


Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.

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