I have three pieris growing together in a small cluster. I noticed this morning that they all have a marron/brown discolouration on the leaves. It appears to be within the leaf, i.e. not a rusty mould deposit.
It would be fair to say that the plants haven't really thrived since I planted them and the leaves are relatively pale. We have a very acidic and sandy soil, could this be the problem?
Although they are evergreen they do lose leaves intermittantly they love acidity too might be worth mulching them with something peaty this year to improve the soil structure a bit as the worms pull it down