American Nursery and Landscape Association
Phone: 202.789.2900
Fax: 202.789.1893
http://www.anla.org/
Click the link "About the Industry" at the top of the page. Browse articles on the page that opens.

Professional Landcare Network (PLANET)
Phone: 800.395.2522
Fax: 703.736.9668
E-mail: info@landcarenetwork.org
http://www.landcarenetwork.org
Select "Certification" from the top menu bar. Also, select "Planet Campus" and then "Students."

Professional Grounds Management Society
Phone: 800.609.7467
Fax: 410.752.8295
E-mail: pgms@assnhqtrs.com
http://www.pgms.org
Browse articles on the home page, including information about certification.