I spent this week of my internship in the weeds without ever leaving the office. Last year the Northeast Exotic Plant Management Team inventoried plants at Green Hill (part of FRLA) that are considered invasive in Massachusetts. The team recorded nineteen different types of invasive plants (weeds) on the property and now it’s our job at the OCLP to figure out how to manage this infestation.
When Isabella Stewart Gardner owned Green Hill this part of the property was maintained as a meadow edged with rhododendron shrubs. Re-establishing a meadow on this parcel today would not only be historically accurate and beautiful, it would also function as habitat for pollinators, nesting birds, and foraging mammals. However, before meadow grasses and wildflowers can be planted at Green Hill, the weeds have got to go.
This is a deceptively complicated task. The nineteen different types of weeds cannot all be eradicated using the same methods. This is because effective methods depend on a variety of plant form specific factors such as growing season, life-cycle, and means of propagation. Likewise, some weeds can be removed after a single treatment, while others will take multiple growing seasons to fully remove from a site. Garlic mustard (Alliaria petiolata), Oriental bittersweet (Celastrus orbiculatus Thunb.), Japanese knotweed (Polygonum cuspidatum Siebold and Zucc.), and multiflora rose (Rosa multiflora Thunb.) can all be expected to take several treatment applications over multiple years to remove.
Treatment methods generally fall into one of three categories: manual, chemical, or biological. Manual methods include hand pulling and repeated mowing. It is important not to mow rhizomatous species, as these are plants that can propagate from nodes left in the ground. Chemical treatments require herbicide that is applied to the plants by a variety of means. Biological controls involve discovering an organism that will feed on and kill the invasive plant. Goats are a fairly common organism used to control invasives.
Re-establishing a meadow among the weeds will be a long but worthwhile endeavor. Luckily, we have help developing strategies for weed management. Plant Invaders of Mid-Atlantic Natural Areas is a particularly helpful guide.
Until next week,