Hi got a number of buxus plants and thinking of this layout
What would you put in the centre a conifer was suggested but i felt maybe a standard rose or a weeping willow or maybe a cherry tree.
or an acer griseum or a Tibetan cherry for its their wonderful form and bark. An obelisk with a clematis or rambling rose. A statue on a plinth or a large pot on a plinth with seasonal planting - skimmia an divies for winetr, bulbs for spring, whatever you fancy for summer. Depends on available time and budget.
Not a weeping willow. Far, far too big.
What about a standard (not a rose) I've just planted a standard holly 'Blue Angel' that has loads of berries and would complement your box.http://www.jparkers.co.uk/plant-0001847/holly-blue-angel/
You do need something to add height,
As it is such a formal bed I can't help feeling that a weeping tree would make it more 'untidy' and less formal
Promise me you won't use a weeping willow, or one of those pink/white/ green willows
ok willow is out but i'm up for more suggestions the bed is about 12 feet in diameter, think its quite hard to be informal with the buxus.
Blackest - stick with formal if you're having the box cones. Think Italian - a standard bay would be the answer but it would need protection in winter so a holly is a great alternative.
Agree with nut- those pink/white/green willows ....
But it's your garden remember and it depends what you like and how much time you have to maintain it.
Are you going to render the retaining wall blackest?
I would lighten the formality with an amelanchier. I will post a picture of the one in blossom in the Bristol Univ. Botanic Garden this week and a close-up of its blossom which gives lovely little edible fruit in the autumn when the colour of the leaves is spectacular.
Wants to go reaaaaaaly formal? A cypress! With some care (and I´ve seen it),
you can alternate buxus with some flowering shrubs like potentilla, geum, azaleas...
Or low annuals (to highlight the buxus): aubrieta, snow-in-summer, basket of gold...
I'd go with an obelisk then you can grow climbers through it. If the plants your try don't suit, easy enough to whip them out and plant different ones. The cypress idea would look impressive, too.