Sea Holly Plant
I started Sea Holly from seed this season, planted it in containers. Now I find out that it doesn't always bloom the first year. I want it in the same container next year, but live in zone 4. What do I do with the containers over the winter?
After the plant has gone dormant, I would put the container some place cold but protected. In a container, think about duplicating a zone 6 environment. As a side note, sea holly has a very long taproot, which doesn't make it a good candidate for container growing, but that's no reason not to try. Should be an interesting experiment. Here's some more information on these plants: https://www.gardeningknowhow.com/ornamental/flowers/sea-holly/sea-holly-flowers.htm