Zone 5 is unforgiving to even concrete. You may need to go with either wood or metal. There are patterns out there and you could use a composite wood product and make your own.

tj

What about fiber glass planters in your zone?
I thought you could use concrete planters in zone 5 but not in direct contact with the ground and had to be planted with a woody perennial, a tree or shrub. The plant should be hardy to one zone colder so you'd need a plant hardy to zone 4.

I have invested in many large glazed pots over the years - different colors for different areas in my gardens. I leave large glazed ceramic pots outdoors in zone 7 coastal - we get hard frozen ground from early December through March and the occasional blizzard with many feet of snow. I have found that the thick ones made in Vietnam are frostproof for me. Be sure to punch drainage holes in the bottom of them.

I have recently begun to use plastic liners in some of my newer ones, however, that I have gathered around my front door. When we buy trees or shrubs or perennials to plant, I save the large plastic tubs/pots and "fit" them to the large glazed pottery - sometimes trimming the height so it doesn't stick out above the rim of the pot, and for the tall pots turning one upsidedown on the bottom and sitting another right side up on the top. Makes it easy to pull out the tender plantings and add greens for winter decoration.

seagrass