Many local governments offer drop-off and/or curbside collection of yard trimmings not composted by homeowners. Drop-off sites work best with residents accustomed to delivering their household discards to landfills or transfer stations to avoid the costs of a curbside collection program. Curbside collection is more expensive than drop-off but typically garners higher participation and diversion rates. The higher operational costs of curbside collection programs can be offset by:

• Decreased disposal costs (tipping fees);
• Increased landfill life; and
• Potential revenue from compost and/or mulch sales.

Yard trimmings collection programs might occur seasonally or by request depending on where you live.

Source: http://www.epa.gov/epawaste/conserve/materials/organics/yd-basic.htm