I have 2, one red and one yellow/green. The red one is now mature and I have just hacked it right back. The yellow/green one is only a couple of years old and I shan't tackle that until it is about 5.

Hi
Now is the time to layer your dogwood if you want more plants for future use,
Its a simple things to do just select one of the long lower
stems and using a blade cut a slight slit "not to long or to deep" and then make a small 2 inch deep and about 4 inch long trench in the soil place the cut stem 'still attached to its main bush' and pin this stem down "use a piece of wire for this push well into the ground so it holds the stem in place and it wont pop out of the soil,
Now cover the stem with the soil you removed, water it and for get about it until november time,
this cut stem should have it's own roots by then and you have a new dog wood tobe planted in your garden,
(remember to sing happy birthday to the stem as you remove it from the bush)

Thanks, may I will take a conservative approach.