I was surfing around for information about my eucalyptus tree and I came across this site. Rich Farm Garden offers seeds and plants for a wide variety of flowers, herbs, trees and shrubs. They also have equine-related items as well as greenhouses and agricultural items.

Some of the most beautiful flowers I ever grew in my garden were peonies and poppies. Unfortunately these plants aren't expected to do well much past zone 9 so all I can do is live vicariously through others such as Commonwealth Nurseries. In business since 1981, Comnur is located in Worcester, Massachusetts and appears to ship anywhere in the US. They offer a wide selection of perennials and groundcovers as well as statuary and outdoor furniture. The owner also provides landscape design and consultation.