All us gardeners love Hydrangeas don’t we? Well I do, if only they didn’t take up so much space. I suffer a little to have to prune them back hard every year. I guess it is the best way to invigorate strong new growth.
As for colour, I never felt the need to chemically force a complete change of colour and I have yet to find out for myself whether it can be done. I can say that on one occasion, I did manage to really enhance a pink to a much darker, well… pink, simply by applying my home-made organic fertilizer on a regular basis.
There are two main reasons for a Hydrangea not to flower:
Firstly, a dry spell during a critical phase. To be safe, keep yours watered all year round (although they will stand midwinter dry conditions, if you must..) and to be completely sure it’s best to install automatic irrigation.
The second reason could be lack of sunlight, so you might have to transplant to a sunnier spot in the garden.
One way to have a brilliant show of flowers every year, is to keep your Hydrangea in a pot like I do. I have it in a sunny spot during spring until I can see the minuscule little flowers in the buds developing, then I move it away to brighten up a more shady location where the flowers last much longer.
One good tip to keep them happy: a cool shower on those hot summer days.