Invasive Plants

The Observatory has worked on Maine Coastal Islands National Wildlife Refuge (MCINWR) islands for a number of years detecting invasive plant species.

Glen Mittelhauser sprays a 45% vinegar and citrus oil solution on invasive Wild Radish on Halifax Island. Although the contents of the spray may sound like salad dressing, it is much more potent than the 8% vinegar in your cupboard!
(Photo by Troy Canham)

The invasive plant species documented during these inventories include:

  • Purple Loosestrife (Lythrum salicaria)
  • Garlic Mustard (Alliaria petiolata)
  • Canada Thistle (Cirsium arvense)
  • Bull Thistle (Cirsium vulgare)
  • Coltsfoot (Tussilago farfara)
  • Narrowleaf Bittercress (Cardamine impatiens)
  • Asiatic Bittersweet (Celastrus orbiculata)
  • Wild Radish (Raphanus raphanistrum)
  • Garden Valerian (Valeriana officinalis)
  • Bittersweet Nightshade (Solanum dulcamara)
  • Japanese Barberry (Berberis thunbergii)
  • Glossy False Buckthorn (Frangula alnus)
  • Morrow’s Honeysuckle (Lonicera morrowii)
  • Salt-spray Rose (Rosa rugosa)
  • Japanese Knotweed (Fallopia japonica) 

(Check out the Island Plants Map to see what islands these species are on.)

Some of the invasive plant populations we have documented are small and spatially confined on small islands with a good possibility that they can be controlled.  

Project Lead

Glen Mittelhauser
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