Crocosmia aurea reaches on average 120 centimetres (47 in) in height. It grows from basal underground corms with long stolons. The basal, alternate leaves are cauline, linear, with a distinct midvein and entire margins, about 20–30 millimetres (0.79–1.18 in) wide. At the end of the flower stalk they have colourful branched inflorescences of bright orange to red flowers, reaching on average 40 millimetres (1.6 in) in diameter. The flowering period extends from June through August. The fruit is a capsule, with small blackish and round seeds. The plant can also be propagated by dividing the clumps of corms, fleshy underground stems similar to bulbs.