Weeds Weeds in parking lots, walkways, under fences and similar areas Weeds are often defined as plants growing in places where they're not wanted. In some cases, the designation of a “weed” can be quite subjective such as a dandelions in a lawn which affects the aesthetics. In other cases, weeds are unwanted because they are harmful to people such as poison ivy or thorny plants. Finally, weeds can be unwanted because they grow in areas intended to be free of vegetation such as parking lots, walkways, fence lines or infields.

Cultural practices for weed management

• Proper design and construction reduces the need for weed management For example, placement of concrete or asphalt mow strips under fencing or backstops provides long term weed management. Most landscape areas can be designed for either long term weed exclusion or mechanical weed management with mowers or string trimmers.
• Install posts 8 to 12 inches inside the edge of the pavement, when fences surround paved playing surfaces such as basketball or tennis courts.
• Use landscaping fabric in plant beds and under stone or brick walkways.
• Retrofit existing cyclone fence lines by pouring a 16 inch concrete or asphalt strip to cover the soil under and beside the fence. Retrofits can be done in stages over several years as budgets permit.
• Mulches such as bark or compost inhibit weed growth by blocking sunlight. Apply mulches immediately after the ground is disturbed or plants are installed. Mulches should to be 3” to 4” thick. Reapply mulch periodically.
• Suppress weeds on baseball infields, running tracks and other bare soil areas using periodic shallow cultivation with a tractor mounted rotary harrow, also called a rotary hoe or power rake.
• Use hand weeding, sting trimmers and mowers wherever possible.
• Plant groundcovers with rapid, spreading growth habits between shrubs.
• Plant fast growing annual flowers such as sweet alyssum, farewell to spring and scarlet flax in bare areas between bedding plants or shrubs.
• Seal cracks on asphalt surfaces. If weeds are already present, control them with flamers prior to sealing.

Chemical weed management

• Chemical control of weeds should only be considered when cultural controls have been exhausted or are unrealistic.
• In Maine, herbicides can only be applied at schools by a licensed pesticide applicator and should be applied when school is not in session (weekend or summer). Be sure the treated areas are posted to prevent accidental exposure.
• Both selective (broadleaf or grass killers) and non-selective herbicides are available. Consult the resources in Section 6 for recommended products and refer to the fact sheet on Choosing the Right Pesticide to identify a low risk product.

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