How to Fertilize round-leaved rhododendron?
Ericaceous fertilizer monthly from spring through late summer

round-leaved rhododendron · Rhododendron orbiculare
Grow in moist but well-drained, leafy, humus-rich acid soil in part shade with shelter; tolerant of sun if soil is reliably moist; see rhododendron cultivation
Ericaceous fertilizer monthly from spring through late summer