Anyone know what perennials that are easy and fast growing from seed?
A lot of perennials will flower late in the first season if you sow them early but they won't now. It's a good time to sow perennials though. They'll flower next year. I used Chiltern Seeds to build up my collection, they list the quick flowering ones
Then, for later on, they have some much more interesting seeds
The best tip I can give is to pick the seeds that are the cheapest in the catalogue/website. It usually means they will grow very easily.
Rudbeckias grow quickly and they tend to pull through the winters with me. Also Gaillardia Goblins are quick growing, often flowering first year.