Edie,
No, I don't think it's too cold for you to grow and bloom brugs. The only thing I can think of is that they need more fertilizer, but you wrote "...watered with Miracle Gro all summer." Did you fertilize at every watering or often?
Gail

Brugs in general need lots of sun to perform well. I grow 99% of mine in full sun. We have very hot summers here and they do very well.

If your not picky about what plants you have, try some like Frosty Pink and others that perform well. Then every fall get cuttings and keep them for new plants the next year, that way you could avoid having to overwinter big plants.

I would also fertilize every week with a liquid fertilizer and think about buying a bloom booster to add to the fertilizer. This could help you get more blooms .

All great advice here. I might also try taking larger cuttings if possible and try leaving a Y on them to kinda get a jump start on next year. Sometimes this works. I agree on getting some reliable bloomers.

Thanks so much to the three of you for answering and for encouraging me to keep trying.

Gail, I watered with MG with every watering, but not every watering came from my can. Maybe I should have mixed the fertilizer solution stronger. We had a very rainy summer. I think I watered half the time, and Mother Nature the other half. This saved the lives of a lot of my plants, because this apartment has no outside connection for water. The apartment's on the second floor. When I water, I fill a watering can at the kitchen sink, go outside, down the open wooden stairs and around to the front of the house. Apply water, go back upstairs, repeat. It's very tiring, tedious and time-consuming. If next year's a dry year or even a normal one, I fear I won't be able to keep up with the watering. I have a miniature jungle of tropicals. I'm trying to pare it down and it's not easy for me. Love them all.

Ednam, I put them in the ground-level space I thought had the closest thing to full sun. With the number of cloudy days we had, that might not have been enough. I'm allowed to put plants in three places here: (1) in-ground bed along the west side of the house, (2) raised bed between the west bed and an apple tree, or (3) the covered south-facing deck on the second floor. I put the brugs in their pots on top of the raised bed, with many other potted plants. Maybe next year I can put them on the landing where the stairs meet the deck. That's a small space, but it's not covered. This summer I had potted herbs there for easy access from the kitchen. There's definitely room for a few pots without blocking the stairs.
Also, I thought Dr. Seuss was one of the more reliable bloomers. Am I misinformed? I think Select Seeds carries Frosty Pink. I was pleased with the (non-brug) plants I ordered two years ago. Have any of you bought a brug from them?

Sultry, I've never taken brug cuttings. Is it difficult? I'm still growing the original plants. I carried them over entire, hoping to get a jump start that way. None of the four has a Y. The pink one that had a Y lost it when it froze, and didn't grow a new one. Visualize a broom handle stuck in the center of a pot, with a few leaves on top. They're dropping leaves now. One's already naked. The pots are what's eating space. Would you recommend cutting them at soil level and rooting them, so I could carry them over winter in a single pot? Are they hard to root when they've gone dormant? Would it be safer to keep them on their current roots but do some major root pruning?

Again, thank you.

YOu are a tireless soul for sure

Good for you making such great efforts to grow interesting plants.

Does seem lot of work for you

I am in Canada just out of Toronto area and do get blooms but my plants although in pots are right outside

One thing I might suggest and I did myself this year is to repot all the plants fresh with nice new rich soil Made a difference in the blooming for sure this summer

I washed out the pots with a bit of bleach as well before re potting Just in case.

I know the Y is important as well

I think is important when you bring the plants in at least for Brugmansia, or in your case have them in during winter, to take all the elves off and thus avoid that white fly