If this is the wrong forum, I apologize. I am brand new here. Please redirect me. However .....

I have a small, paved backyard, west facing, sheltered but not that sunny. Maybe 9 hours direct sun during summer. 52 degrees north, NW England. So my garden is all containers. Chinese and Japanese theme throughout. Question is, in one sunny corner I have 2 decorative Bamboos, a Chusan Palm and a Japonica all in large tubs, all thriving. I have made a fake wall across a corner of the yard and featured these 4 plants within it. This spring I'd like to add a splash of colour in that plot. Just one. I was thinking Japanese/Chinese Lily, to go with the theme.

I would prefer that this Lily not be too tall, or too 'in-your-face', because I want it to add to the feature, not take it over.

I would be grateful to any of you who come up with suggestions. You know way more than I. Thanks in advance