I look forward to creating and installing summer planters every spring. We try to shop locally as much as we can. One of our favorite suppliers is Longfellow's Nursery in Manchester, Maine. Almost all of the annuals came from there- with the exception of a truckload of herbs grown by Chaz and Linda Gill from Kennebec Flower Farm.
Hunting for product can be a lot of fun, but almost always requires multiple stops. Some nurseries are known for more unusual annuals, others are known for having larger quantities of the staples.