Do you mean red twig dogwood? If so (and this is true of lots of colorfully-twigged plants), the color is deepest on the new growth, so if you don't keep cutting out the old stems you won't get lots of new growth with vibrant color. It's one of the reasons that I limit my number of red and yellow twigged dogwoods, as I want to keep the maintenance low. But perhaps you are referring to another genus.

Here is a link that might be useful: Form and Foliage

they would be better pruned thru 'rejuvenation pruning' .. removing up to 1/3 per year... rather than sheared like a hedge of privet ...

google the term

you better have at least 10 feet wide of space ... for a good showing ... they are not a small plant

ken

Here is a link that might be useful: e.g. that second pic

Rejuvenation pruning is correct! I could use a little myself...