Problem
Why does my red bistort 'Rosea' have yellow leaves?
Persicaria amplexicaulis 'Rosea'
Yellow leaves on a red bistort 'Rosea' usually has one of three causes — watering, light or a pest. Walk through them in order before reaching for a treatment.

Most likely causes
Detailed cause-by-cause guide is being prepared. In the meantime: check watering rhythm, sunlight match, and any visible pests on the underside of leaves.