I just had a question from a friend on how to correctly prune hydrangeas which prompted me to do a post so it could be of benefit to other viewers of my blog.

I have two different types of hydrangea in my garden; the mophead type and hydrangea paniculata which has beautiful pink tinged blooms in the fall.  

I pretty much use the same method of pruning on each type.  You have to be very careful where you prune and when you prune as hydrangeas bloom on old wood and you can very easily cut off the blooms for the current season.  I cut off any dead flower heads back to the first set of shoots.  With the mophead type I prune out any dead wood from the base.  It is easy to find these branches as they are very brittle.  With the hydrangea paniculata I cut out any cross or dead branches and to keep the bush open in the centre I do cut out some of the newer shoots at the base.   If you want to trim back a large hydrangea bush it would be best to do that in June or July so that it will not upset the blooms for the following year.  

One other tip – if you want to change your pink hydrangea to blue you just need to adjust the ph balance of the soil, i.e the soil needs to be more acidic. If you are looking for natural products you can use old coffee grounds or compost.  (My mother-in-law would just put rusty nails at the base).  Conversely, if you want the blooms to be pink you can just add lime to the soil to make it more alkaline.  

Thanks for reading.