The hollyhock, Alcea, is a classic English cottage garden plant, forming tall erect racemes of large, fully open blooms from summer to early autumn. Plants are typically perennial, but they’re often grown as biennials due to their susceptibility to the fungal disease rust, which can disfigure leaves.
Alcea ‘Black Knight’ bears incredible, single to semi-double, almost black flowers in dramatic, tall flower spikes. It’s easy to grow and perfect for planting in groups at the back of a sunny border. For best results, grow in moist but well-drained soil in full sun to partial shade. Cut down Alcea ‘Blacknight’ after flowering to encourage fresh basal growth.