How to Prune Viola 'Sulfurea'?
Deadhead to prolong flowering. After flowering cut back vigorous plants to keep compact

Viola 'Sulfurea' · Viola 'Sulfurea'
Grow in fertile, humus-rich, moist but well-drained, neutral to alkaline soil. Ideally choose a position with winter sun and summer shade, such as under deciduous trees, shrubs or hedges
Deadhead to prolong flowering. After flowering cut back vigorous plants to keep compact