How to Fertilize Clematis?
Monthly during growing season with low-nitrogen fertilizer

Clematis · Clematis spp.
Also known as: Clematis, Leather flower, Virgin's bower
Grow Clematis in moist but well-drained fertile soil, ideally with the roots kept cool and shaded by other plants or a mulch layer while the top growth enjoys full sun or partial shade. Water regularly during dry spells, especially in summer, to keep the soil evenly moist. Apply a balanced liquid fertiliser every 4-6 weeks from early spring to midsummer. In autumn, mulch around the base with well-rotted organic matter to protect roots from frost. Good air circulation helps prevent diseases.
Monthly during growing season with low-nitrogen fertilizer