Posted: 05/09/2014 at 10:44
I had the same issue with a few Pyracanthas I put in last year. I picked off the affected bits and they are all fine now, even the worst one which had been an 'end of summer bargain' so it was a bit rough looking anyway. They're pretty trouble free on the whole though. As Stephen says they like a reasonable amount of drainage, although two of mine are actually in quite heavy ground. They'll also grow quite well in shade although they prefer sun.
You say you've got them recently Ali, so have you watered them in well enough initially? Sometimes it can be that simple, especially if they're quite large plants. That can be trickier than getting small plants established.