You don't say how large your containers are. Miscanthus, as in the photo above, is a good idea. You could consider, as your display develops, adding a standard shrub such as a holly that would have berries in winter. There are also columnar crab apple varieties such as 'Evereste' that can be grown in large containers and offer two seasons of interest.
@Cambridgerose12 they’re about 3 feet high. However, when I tried them in this bed they didn’t look right anyway. This was last year so they now stand either side of the front door and suit their position much better. However, you mention trees for pots and I have been warming to that idea since watching Garden Rescue this year! I’d like a couple in the garden so will look into that variety - thank you!
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