How can I add plants to my small deck in Northern Michigan?

Boxwood

You can add plants in terra cotta planters. I like these because they maintain moisture better than pastic. Cedar is another option I like. I would try herbs shoot for perennials and a few annuals. You can cook with them as well as enjoy so it's a win win with limited space.

This herb bed is in the ground but it may help you to visualize what they could look like in pots.

https://www.gardenupgreen.com/2016/10/grow-a-bed-of-herbs.html

Is it partial sun? Petunias do well in sun or shade. My flower pots are all tin buckets, tea pots etc. Just drill a few holes at the bottom for drainage. Use the miracle grow potting soil & all you have to do is water. When you look for flowers look on the tag that's place in the pot, it'll tell you either full or partial sun or shade. Gerber daisies all so do well in either. You need to dead head you flowers which means clipping off the wilting or dead flowers, this will allow for more blooms.

Whats your weather and loweat temps.

Lowest temps opps.

Hi, Leslie, you're in zone 5, so nursery grown dahlias, marigolds, basil, thyme, petunias, sweet potato vines, cosmos, hen and chicks sedums, gladiolias, coreopsis would all work in sufficiently sized containers with good soil, good draiinage, fertilized, sufficient sun, watered, and topped with a mulch layer.

If you have more shade, try astilbe, Kong Coleus, Sunpatiens, Brunnera, Fuscias, Lamium, Acuba.

I feel your frustration...this area had too much rain and too few days of decent weather for the last several years.

Thanks for all of the advice...I'll post a pic this summer!