Well, the smell is as sweet as ever, but the leaves have gone yellow
overnight. I thought that this plant was supposed to provide leaves for
most of the year.

It's a real pity, as it was my favourite plant. I watched it grow from a
seedling to a metre tall fountain of licorice with absolutely no
maintenance required.

The ground isn't too dry, or wet. It recieves dappled shade a few hours
a day. A few stalks have aphids plus ants, but share and share alike, I
say.

Is this yellowing normal, or can I take corrective action? Or at least
learn the cause of the current crisis and so take steps in the future?

Thanks,

Col