By Ladyoz
United Kingdom 
my mum has pittosporum tree which my father planted 50 years ago, shes getting an extension built and would like to know can it be reduced in size and thickness and will it still bloom. it stands at about 25 feet and 10 round, as my father is no longer with us she dosent want it removed
1 Jul, 2016
Difficult now, possible around May time, but hard cutting back might mean it doesn't respond well. It's just a bit late in the growing season to start cutting off a lot of growth, but if the extension depends on it, then you'll have to chance it. The next problem to consider is this - if the extension is going to be within 5 or 6 feet of the Pittosporum, then digging out for the foundation is likely to disrupt the root zone of the plant, which may cause it to die anyway.
What you could do is try taking cuttings immediately, semi ripe ones - they'll need to be kept under glass in pots this winter and then either potted up or planted out next spring. More info on semi ripe cuttings below
https://www.rhs.org.uk/advice/profile?PID=404
1 Jul, 2016