How to Fertilize large-leaved rose?
Rose fertilizer every two to four weeks from spring through late summer

large-leaved rose · Rosa macrophylla
Grow in full sun with fertile, humus-rich, moist but well-drained soil. Tolerant of poor soils. Mulch with well-rotted organic matter in late winter or early spring, and for best flowering apply a general rose or shrub fertiliser in early spring and again in early summer. See rose cultivation
Rose fertilizer every two to four weeks from spring through late summer