What invasive plants can be successfully controlled using solarization? What is the most effective procedure? What are the drawbacks of this method?
Solarization of a site to control invasive species would not be an option for most situations. Solarization requires the ground to be covered with clear plastic with the edges sealed and the plastic left on for 6-8 weeks in order to raise the temperature under the plastic high enough to kill plants and seeds of the invasive plant. This method would be limited to small areas in full sun with no desirable plants coexisting with the invasive plants. In New England many of our invasive plants are problems in the forest edge or understory where there would not be enough sun for solarization to be effective. Smothering plants with black plastic or other material to starve them of light may be a non-chemical option for the shade. Solarization could be considered for a site in the sun where all the vegetation could be killed or a site that had already been stripped of vegetation and the goal was to kill the seeds of the invasive plant in the seed bank. Another use for solarization in the control of invasives is cutting or pulling the plants and bagging them to be put in the sun until they cook and no longer contain any viable form of propagule, be it seed, root, or rhizome.
Tricia Diggins, Senior Gardens Horticulturist, Wellesley College, MA
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