I have just planted annuals in mine. Will be interested to hear what others say concerning viability of shrubs.

Annuals do great in the one I have. This would be in an area that my dog spends a lot of time and I'd like something more permanent. I'm afraid dog pee would ill anything planted directly in the ground.

One tip I learned from a Professional landscaper is to check which shrubs or trees grow in your Zone - and then subtract one zone if you're planting in a container. Since there is less soil and less protection from the cold the roots are more vulnerable. Dwarf Alberta Spruce is popular and evergreen. There are also new varieties of Crape Myrtle that are shrub size.

This site has other helpful info:

https://opusgrows.com/blogs/journal/constrained-by-the-city-try-container-trees

The recommendation is really for a plant that is hardy to at least 2 zones lower than yours if you intend to leave outside all winter. For a zone 5b location, that means you are looking at plants hardy to zone 3. That would eliminate any possibility of a crape myrtle and seriously limits whatever else you might consider.

Dwarf Alberta spruce is a good candidate. So is the native ninebark, Physocarpus opulifolius. Other choices could include alpine and clove currant, Hydrangea paniculata or arborescens, Cornus sericea, a few viburnums (lentago, opulus/trilobum), Amur maple.

I have planted a variety of bulbs in very large pots. You can either leave them there over the winter or dig them up to store inside. We have gophers and if the bulbs are planted in the ground they either eat them or move them.

My experience planting in a wine barrel became a haven for ants! I had to remove the barrel due to infestation. I am not sure if it depends on where it is placed in your yard, patio or porch?Mine was placed similar to what this picture shows.

it needs holes in th bottom of the barrel. a butterfly bush might fit your desire.

Butterfly bush is iffy even in the ground in a zone 5. Will not survive winter in a container.

I have planted a couple smallish trees in wine barrels - a coral bark maple and a contorted filbert. Both thrived and grew through the bottom into the ground. The problem being that the barrels eventually rot and you are left with no way to replace it because the roots of the trees are partially inside it and partially in the ground.

Oly, that's a very good point but I doubt that would be a big concern in a zone 5 :-) In our location, sure, but I still got a good 8 years or so out of my half whiskey barrels before they rotted out.

In our area, the tipped over wine barrel with the flowers spilling out is very popular.