Sorry but I don't have a photo right now but could have one for the weekend.
I have a young 2yr old white forsythia and the leaves are largely a more yellow colour than I think they should be. In fact they shouldn't be yellow at all. They are showing dark green veins too. Some leaves are forming brown patches too.
It's not a big plant at the mo so to start with I thought I would put it into a ceramic pot with general purpose compost with grit on top. It's placed in full sun in a corner that is SE facing. It gets full sun from roughly 8am until roughly 2pm. I could move it so its another couple of hours if needed but then it wouldn't be in a sheltered position.
Could it be suffering from iron deficiency?
But before I feed it with a dose of sequestrene does anybody have an other suggestion or thoughts?