Mechanical control includes any physical means of removing or destroying the invasive plants.
Mechanical control methods alone are rarely enough to completely control an invasive plant problem, though they are a good way for homeowners to begin managing property.
Pulling and Digging
This is the most common form of mechanical removal. Isolated patches of plants can be managed this way. Pulling and digging are preferred methods for using large groups of volunteers. This works best when plants are easy to pull (such as garlic mustard, dame’s-rocket, or seedlings of invasive shrubs and trees). There is a degree of trampling and soil disturbance to take into account.
Care must be taken to remove the entire root system of the plant when pulling and digging. Many invasive plants may look dead when the aboveground portions are removed, however they can still regrow vigorously from persisting roots beneath the soil. In fact, failing to remove the root system might trigger a more vigorous response from the plant.
Plants should be bagged and removed from the site, or placed on logs or rocks as to ensure the roots have no contact with soil.
Though mowing cannot completely remove the invasive plant, when timed precisely, it can effectively control the spread of the infestation.
Because mowing cannot prevent the resprouting of plants, it needs to be repeated within a growing season to maintain effective control. This will maintain the system in an earlier successional stage, which may or may not be a manager’s overall site goal.
If greater control is desired, mowing as soon as plants flower but before they release seed can prevent the population from expanding in the next season.
This method can be used to control invasive plants, but it is not a fail-safe method. Much depends on how invasive and native plants are competing for resources, and how fire is affecting the ability of native species to recover and thrive. Often the disturbance from fire can open sites to invasion.
Fire effects on invasive plants is a complex situation which this web site is unable to address adequately.
This method can be used for a low cost control method for isolated areas of invasive plants.
Begin by cutting or mowing the area to reduce the ground cover of the invasive plant. Next, cover the infested area with a thick opaque tarp or carpet. This will block sunlight from reaching the plant, making photosynthesis and any further growth very difficult for the plant.
Stems may try and poke through any weak spots or seams so be sure to keep watch over the tarp. Tarps can be covered with layers of soil and mulch and new plant beds can be planted above as well.
This can be considered mechanical or biological control.