Which Plants for These Whichfords?

Back in the year 2001 when I was working at the legendary Hortus nursery in Pasadena, CA I purchased these four handmade terra cotta Whichford pots from a container load the nursery had imported. Made by a family-run business in a small English town, this was decades before anyone in the US was importing this brand from the UK. (Gary Jones was and is a genius.) These pots were expensive even then.

When I moved from California to the East Coast in 2004 to join Cottage Living magazine, I dumped them behind the shed at my parents house in New Hampshire and forgot all about them. I was recently clearing the backyard and unearthed them from under a pile of leaves and debris. These containers have been sitting outside unloved in the snowy, rainy, muddy weather for 20+ years and I think they look even better than the day I bought them. Yes, it was painful to pay up (isn't it always?) but an investment in the garden always seems to be rewarded in the end!

Now the question is, what should I plant in them in my zone 6 Maine garden? I’m thinking flowering shrubs or evergreen topiary. What do you think?