How about a Sorbaria? Their leaves in Spring are superb, beautiful pink and bright yellowish green, and they can grow in a large pot in the sun. In fact it is better to have them in a pot as they can throw up suckers in the open ground and become a thicket! They have fluffy white flowers in early summer, but are not evergreen.
I have Sorbaria Sem in the open ground, but I have given suckers to my siblings who grow them in pots and they have had no problems with them. If they grow too large you can cut them back, but Sem is quite a small(ish) variety anyway. I've attached a link, but they are quite widely available from many garden centres now.
www.bluebellnursery.com/Sorbaria/5743348-Sorbaria-sorbifolia-Sem.html