Various varieties of Ilex (Hollies), Arbutus (Strawberry Tree) could do. I have Cotoneaster Cornubia which is semi-evergreen in my frost pocket. Should be evergreen where you live. Lots of flowers which are smothered with bumble and honey bees and excellent for butterflies in Summer and loads of berries for the birds in Winter. Does respond well to pruning so easy to shape.

Consider some of the 'blue' or 'gold' conifers, slow growing etc or a fastigiate form, there are some nice forms of yew. I'd go to your local garden centre and see what 'dwarf' conifers they have. Dwarf just means slow growing. The label will say something like 2ft in 10 yrs.

I assume you don't mean shrubs.

Thanks Jimmy and Eileen. I’m not sure about shrubs though I have considered Pieris Forest Flame. The “tree” will be in a central, large pot in a sunny spot with a Prunus kojo-no mai on each side. The central “tree” will be of a height to give a triangular shape with the two cherry trees.

Since it is in a pot, I assume that you are actually thinking of what's called a "standard"--a short trunk (1-2 m tall) with a bushy or weeping top 50-100 cm wide?

Possibly Tug, I’m not sure. I think I need to hunt around a good GC and talk to someone knowledgeable! Thanks for your suggestion.

Evergreen Sophora microphylla "SunKing Tree"
3m (10ft Hight)
3m (10ft) Spread
Withstand temps down to 10c (14f)
Begins to flower early spring & the Bee's love it :o))

I put mine on my Photos :o))

should that be down to minus 10c [ -10c] ladyessex?

Oh! Yes LOL -10c Duh! Well Spotted LOL x

Thanks Lady Essex!

I think we’re going for a dwarf copper beech … thanks everyone for your ideas.

copper beech isn't evergreen and doesn't retain its dead leaves though!

Eileen, you’re right of course, but our dwarf one keeps its leaves for eleven months of the year, so that will do me 🙂.

our hedge keeps its leaves but the tree doesn't and the neighbour's copper beech donates its leaves to our garden too grrr