Can anyone recommend an online source for re-blooming irises? I'm not sure where to even look. I want to make sure I buy from a reputable company.
I'm looking for Dahlias too.
Here's a link to AIS with many links to commercial growers of iris. Reblooming is noted on cultivars that so behave. In zone 5 any fall rebloom will probably be hit by low temps. and therefore be mush.
I would inquire on the Bulbs forum about dahlias. They would need storing during your cold winters.
Here is a link that might be useful: http://www.irises.org/links.htm