Clematis problem

shanekm2003

I planted a clematis that had grown well in a pot for four years . This year it’s producing lead buds that open up and then shrivel up after a few days . It’s planted in well drained soil and deep, it’s covered by a thin layer of slate to keep the roots cool. Any ideas please ? 

Fairygirl

Probably needs to be in a bigger pot, or better still, in the ground, but most likely reason is that's it's too dry. That's my best guess, but it also depends on the type of clematis.

Any plant in a pot long term needs a good soil based medium to grow in, which also needs refreshing every year as the roots will eventually use up everything in there. There's a good chance that there isn't much soil left in the pot. 
If you have a pic, that will help enormously. 

Obelixx

Starvation and thirst, as Fairy says.   Clematis are hungry, thirsty plants and after 4 years there'll be nothing left for it.