I cant keep hydrangeas alive either. I haven't bought one this year.
The first one I had came with the house, it was established, quite large and beautiful, until dh decided it was roo big and cut it back. He then forgot it was there and I came home one day to find his building stuff stacked in that corner.
It was 27 years ago, and one of the few things I still hold against him- particularly as we've never managed to grow another.
I've also only ever managed to get lavender to grow in a Belfast sink, no idea why other pots and the ground haven't worked but I've rolled with it.