Crocosmia × crocosmiiflora, montbretia, is a garden hybrid of C. aurea and C. pottsii,[a] first bred in 1880 in France by Victor Lemoine.

Crocosmia × crocosmiiflora grows to 90 cm high, with long sword-shaped leaves, shorter than the flowering stem and arising from the plant base, ribbed and up to 20mm wide.

[6] There are over 150 named cultivars within C. × crocosmiiflora including: Those marked agm possessed the Royal Horticultural Society's Award of Garden Merit in 2023.

[11] Crocosmia × crocosmiiflora is deemed an invasive plant in the United Kingdom and the Isle of Man; also in New Zealand, where it is common on roadsides in the northern parts of the West Coast of the South Island.

[13] It is widely naturalised in England and Scotland, especially along the western seaboard from Cornwall north all the way to Sutherland.