Hardy Zones 5-8
Use crocosmia in large groups in the border wherever you need a splash of vivid colour in late summer. Plant the corms outdoors in spring, after danger of frost, in full sun to light shade, spacing them 4-5" apart, and cover with 3-6" of soil. Feed with a 5-10-5 fertilizer when shoots appear and again in midsummer. Apply a heavy winter mulch. Where crocosmia are hardy, dig the clumps up and divide the crowded corms every third spring. North of Zone 5, lift the corms, cut off the stems and store with the soil still clinging to them in a dry potting medium.