How to Prune rhododendron 'Avalanche'?
Usually little pruning is needed. Lightly shape if necessary, removing dead, damaged or diseased shoots. Prune after flowering. Remove spent flowers where practical.

rhododendron 'Avalanche' · Rhododendron 'Avalanche'
Grow in moist but well-drained, leafy, humus-rich acid soil in part shade with shelter; see rhododendron cultivation
Usually little pruning is needed. Lightly shape if necessary, removing dead, damaged or diseased shoots. Prune after flowering. Remove spent flowers where practical.