[AlaninCarlisle]

I have a couple of hydrangeas that have flowered less and less over the past few years. I planted them 30 years ago and am wondering if this is the limit of their flowering life although in all other respects they look healthy and vigorous.

Time to grub out and start again or is there some or other pruning or feeding regime I can adopt?

[mumofstig]

Giving them a good prune and a good dollop of manure, usually does the trick 

[AlaninCarlisle]

Well they've certainly had the good dollops of manure over the years. To be honest, I thought that might have been the trouble and was creating foliage at the expense of flowers

[mumofstig]

Aah! the RHS says

Too much feeding can encourage excessive soft, leafy growth, with plants less likely to develop flower buds and more at risk from frost in colder winters...........................
Hydrangeas are usually robust shrubs. Non-flowering can be caused by frost damage to flowering wood, over-zealous pruning, pruning at the wrong time, or over-feeding with fertiliser too high in nitrogen.

you could try some high Potasium (K) fertiliser to encourage flowering.

[Kristen]

I'd prune them hard and manure/fertilise them too MoS, but depending on variety, its likely they won't flower next year - if they are a variety that flowers on old-wood.  No way around that I think (unless there is a time of the year to prune that doesn't sacrifice next year's flowers?)