When to hard prune evergreen hedges -- holly and box?

Hello everyone

I have to prune back a holly hedge into old wood, it's grown too thick and gets in the way.

I also want to cut into the old wood of a box hedge to give it a more interesting shape.

When is the best time to do this -- the winter when it's relatively dormant or the spring when the sap's rising?

 

Any time from now through winter, I would say. But it would be nice to keep the holly berries as long as possible for the birds.

 

Thanks, I thought so.

Male holly hedge unfortunately so the birds won't lose out!

 

Curiously Howard, the male hollies have female names and vice versa! Somebody had a perverted sense of humour way back . Golden King, for example, is a female. Silver Queen and Silver Milkmaid are males
I prune hollies in late summer and early autumn.
There is currently a rampant disease on box and I think the current thinking is to prune in summer; may be wrong here as I dont grow box as hedging

 

I think if it was me I'd wait until late winter very early spring.
At that time it will green up faster with new growth and perhaps not look bare a twiggy for long.

 

I agree that the bare wood on the holly will look bad.

By the way, does anyone know if there's a power tool, a hedge trimmer, which will do the job? I'd say the branches are 1/4 inch thick maximum?

 

The "secret" with pruning hollies is to do it regularly. Then bare wood is never a problem. I will be pruning ......trimming....a very large Golden King soon and the effect will simply be to help it look neat.
Often people suggest pruning in spring to avoid the "bare" look however hollies can sulk a little even in spring; thus spoiling the spring display. Pruning now gives them a chance to begin making new growth with earlier recovery in spring. My experience anyway