How to Fertilize sweet briar?
Rose fertilizer every two to four weeks from spring through late summer

sweet briar · Rosa rubiginosa
Also known as: sweet brier; eglantine
Grow in fertile, humus-rich, moist but well-drained soil in full sun. 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. Tolerant of poor soil and shade, suitable for hedging
Rose fertilizer every two to four weeks from spring through late summer