Hey there Toni,
Goldenrod is one of the last bloomers for the bees to forage on before winter. I'm trying to avoid the dearths of the seasons by planting these varieties. Outside Pride has many of the seed I've been looking for and so did Ruhl Bee Supply (although they have recently ran out of most) but the shipping is the killer most of the time. If I lived close enough to pick up from the store the prices are okay but shipping is more than the seed sometimes, especially in the quantities I'm looking for. I ran into that same problem when I ordered wildflower seed through Amazon. I was able to find Buckwheat and white sweet clover locally and I'm ordering Lacy phacelia through Ruhl .
How large of an area are you converting to bee forage Toni? Send me a tree mail and we'll discuss it. The 4 plants I've listed in this thread are the start of a longer list that I want to acquire over the long run. Locally the blackberries are the main nectar flow but it is short lived, especially last year. I'm doing about an acre in buckwheat and another 1/2 acre in wild flowers and a large annual flower garden. When it's in bloom this summer I'll post pictures.