To Celebrate Earth Day, Lowe’s is giving out free trees on April 23, 2011. Find out more details and see a location near you HERE. Earth Day is actually April 22, 2011 of this year, so I’m unsure if this is a typo in their date, or if in fact they are giving these out the day after Earth Day.
Call ahead to your location, just to be sure they are participating. You may also want to verify the date with your store.