How to Fertilize rose 'Wilhelm'?
Rose fertilizer every two to four weeks from spring through late summer

rose 'Wilhelm' · Rosa 'Wilhelm'
Grows best in fertile, humus-rich, moist but well-drained soil in a sunny, open position. Mulch in late winter and, to improve flowering, apply a balanced fertiliser in late winter or early spring, and again in early summer. See rose cultivation
Rose fertilizer every two to four weeks from spring through late summer