Question
Hi there, I have 2 large Hydrangeas that are very overgrown and block light from 2 bedroom windows. How do I cut them back without killing them! They are thick with dead, old growth but still manage to come back every year!

Answer
You can remove the dead limbs and branches without any risk to the plant.  Just be sure you use pruning shears that are sharp so you get a clean cut.

Any branch with a leaf bud on it has potential blooms.  Those buds are this year's Flowers; if you remove them, you will be removing this year's Flowers and will have to wait another year before blooming.  This happens all the time -- people want to prune in the Summer and find they have no flowers the following Summer but have no idea why.  Now you know why.

If however they are so lanky and wild and gregarious you feel they MUST be contained asap, cut HALF the longest branches back to the bud closest to the ground and accept that they won't bloom this year; do the other half next year.  You will still get blooms from the unpruned branches, and they may even be larger since there are fewer of them.  Alternately, you can lop off a maximum 1/3 of all top growth at a uniform level to open up the area outside the windows and most likely lose all blooms in the Summer of '08.

Top-dress with a good 3 inch thick mulch of aged Manure or Compost and fertilize ONCE with a liquid Seaweed or Fish Emulsion product to rev up the microbe engines and aid in recovery.

Hope this is clear.  Thanks for your question,

L.I.G.