Horticulture
In this issue:
Unfortunately, our efforts to discourage homeowners from planting new ash trees have not hit the mark in all cases. In the spring, ten Lowe’s stores in Maine (all but Presque Isle) imported 40 green ash trees (four to each store) from Clinton Nurseries with operations in Westbrook, CT and Centreville, MD. All of Connecticut and Maryland are under a federal emerald ash borer (EAB) quarantine. It was not legal to ship those trees to the stores outside of the Maine EAB quarantine (Auburn, Augusta, Bangor, Brewer & Thomaston) and there was no way of knowing if the trees shipped to the stores inside the quarantine area (Brunswick, Portland, Sanford, Scarborough & Windham) were planted inside or outside the quarantine.
Four trees were never sold (one in Bangor and three in Portland) and those trees were destroyed by USDA APHIS and the Horticulture Program staff, but that left 36 green ash trees out there somewhere that we needed to find. Fortunately, they were only one-inch caliper trees which posed a very low risk of EAB infestation, but regardless, we wanted to find them and inspect them for signs of EAB infestation.
As of November 12, with the Lowe’s Compliance staff's help, we have located 30 of the 36 remaining trees. None have shown any signs of EAB infestation. All but one homeowner has agreed to destroy the trees to prevent any future emergence of EAB. Those customers will take advantage of Lowe’s offer to replace the trees or reimburse their purchase price.
We are amazed that so many people have seen our press releases and have responded to our plea and at least one customer has responded to a letter from Lowe’s. The single tree that a customer elected to keep will be re-inspected next season and the year after unless the EAB infestation moves into that area as well. Unfortunately, that little green ash may have a short life unless the homeowner elects to treat it until the EAB wave passes, which could be as long as ten years of treatments.
Finally, although it may be legal to import and sell ash or white fringe tree into Maine’s quarantined areas, we do not recommend it. All species of Fraxinus (americana, nigra & pennsylvanica) and Chionanthus virginicus are at risk of EAB infestation and would need regular treatments with insecticides to keep them alive. Good choices as replacement trees could include Acer rubrum (red maple), Acer saccharinum (sugar maple), Nyssa sylvatica (black tupelo), Betula nigra (river birch), Betula alleghaniensis (yellow birch) or Quercus bicolor (swamp white oak).
More Information on EAB
 Ash tree from Lowe's awaiting destruction.
The September MELeaf included an article about shipping holiday greenery to other states. Now that the holiday season is upon us we wanted to again remind anyone shipping plant material for the holidays that only healthy, pest-free decorations should be sent. Find more information on specific plant health regulations concerning holiday greenery and decorations on our website
 On the flip side, if you receive holiday decorations including plant material from out-of-state this holiday season, it is prudent to check these incoming shipments for pests. Most businesses selling plants are aware of the risks of introducing pests on living plant material, but plant products that are no longer alive also pose a risk of spreading pests, especially wood products that have attached bark. We received notice this week that an invasive wood boring beetle larva was found in another state in a twig wreath that had been been assembled in China. At this point, we are awaiting word from USDA to find out if any of these wreaths were shipped to Maine. If you find pests on incoming holiday plant material and can not easily identify the pest, send an email to horticulture@maine.gov.
The end of 2020 is approaching! Licenses to sell plants are issued for a calendar year; all nursery licenses expire on December 31, 2020. The Horticulture Program will send out nursery license renewal notices just after Thanksgiving. Please review and promptly return the license renewal application. Due to COVID-19 it may take the Horticulture Program longer than usual to process and return your license to you. Submitting your application early will ensure that you receive your license before selling plants in 2021.
- November 19, 2020 - Who's Got Compost? Coastal Maine Botanical Gardens and Maine Landscape and Nursery Association, Green Spotlight Series
- November 19, 2020 - AmericanHort Virtual Retail Tour
- December 3, 2020 - Irrigation Management: Nursery and Greenhouse, Coastal Maine Botanical Gardens and Maine Landscape and Nursery Association, Green Spotlight Series
- December 8, 2020 - AmericanHort Women in Horticulture Interview Series - Genevieve Reiner Mills of Oakland Nursery
- January 4-7, 2021 - Northeastern Plant, Pest and Soil Conference
- January 19-23, 2021 - Virtual Agricultural Trades Show
- Can an Ambitious Breeding Effort Save North America's Ash Trees?
- Approaching Plant Health Systematically
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