The growing season is pretty well done here. Asters and mums are about it.
Head for the coast and see the rock strewn shorline. Not far from the Bar Harbour area when your in Bangor.
My parents live in the Blue Hill area and I get to wander about a lot.
Bucksport, Searsport, Ellsworth area are full of antique shops and other assorted little shops. The town of Bar Harbour itself is a lovely place. Shops are a little pricey and touristy but it has a nice flavor.

Blue Hill Daylilies
Surry Gardens
Hidden Gardens
Fieldstone Perennials (inland)
I don't if Hidden Gardens has a webpage but the others do.

I wondered about the growing season being done. Missouri and Maine are both Zone 5 (although Kansas City, for some reason, is a pocket that is Zone 5b and I hear they're changing it to zone 6).

I haven't been to Busksport or Searsport yet. I love Rooster Brothers in Ellworth. The first time I saw Bar Harbor was in Feb. You can imagine how thrilling that was! A general store and a bar/restaurant were the only two places open. We went again in May which was better. Still a lot of shops closed but they were gearing up for the tourist season.

Thanks for your response and the tips on garden centers.

>>>I wondered about the growing season being done. Missouri and Maine are both Zone 5 (although Kansas City, for some reason, is a pocket that is Zone 5b and I hear they're changing it to zone 6).The USDA zones tell us what the average lowest temperature is in winter. It doesn't relate in any way to length of the growing season or frost dates. A large part of Maine is zoned in 3 and 4.

Sweet Pea Gardens is lovely. Linked below.

Here is a link that might be useful: Sweet Pea Gardens

Drive East to visit Eastport and stop by Raye's Mustard Mill and say hi!

Leasa

Here is a link that might be useful: Raye's Mustard Mill