Posted: 02/08/2012 at 13:46
In my experience elders respond well to being hacked back, even the fancy ones like sambucus Black lace and the golden form. You could plant another clematis such as tangutica Red Ballon to add flower interest later in the season. i have one scrambled up a tree and never prune it. It's loved by bees and the flowers start yellow then fade to a dusky red followed by twirly, silken seedheads.
The general rule for pruning shrubs is immediately after flowering if they flower before end of June. Otherwise prune in late winter/early spring. You will inevitable lose some flowers and thus fruits.
You could also consider hawthorn and honeysuckle for your hedgerow as both provide nectar and fruit for birds and insects. Being thorny, teh hawthorn also lets small birds shelter from predator cats and raptors.
A good garden centre should have hedgreow plants in stock come autumn. Honeysuckle and clematis should be available all through the growing season.