Your local USDA Extension Office
Most people don’t know this, but the USDA is available to help with almost any plant/agricultural question you may have. The Cooperative Extension System is a nationwide, non-credit educational network. Each U.S. state and territory has a state office at its land-grant university and a network of local or regional offices. These offices are staffed by one or more experts who provide useful, practical, and research-based information to agricultural producers, small business owners, youth, consumers, and others in rural areas and communities of all sizes.
Please visit http://www.csrees.usda.gov/Extension/ for more information.