Mine is ok at the minute but someone did ask me, and said theirs had crawlies on the stems and the leaves were curling,has yours got infected with insects?

Hot weather. They're tough, but can get caught by sudden hot spells

thanks for the info. No Poppylinda, no insects there , just curled up withered leaves. I did think it may have been the extremely hot weather Worthy, but wanted to check with others. There seems to be 'green' in the stems, so hopefully it's not actually dead!Just looks awful.

I would cut it down, they are pretty tough as worthy says. It should grow again,I give mine a "trim" every year and it soon grows up again.