Iris macrosiphon aka Ground Iris

Iris macrosiphon, or bowltube iris, belongs to the iris family. It is native to California in the United States. This perennial grows from rhizomes beneath the soil. Kew describes its native climate as subtropical. It grows on grassy slopes and in open woodland. Meadows, sunny hillsides, and roadsides also provide habitat. Its recorded sites lie below 3,280 feet [1,000 metres]. These habitats include both open ground and light shade.

This small iris reaches about 0.7 feet [0.2 metres] tall. Its low height suits the edges of garden beds. PFAF lists it for beds and sunny woodland edges. It flowers from May to June. Each flower has both male and female organs. Insects pollinate the flowers, and the plant is self-fertile. It can cross with several other Pacific coast irises. Seed-grown plants may therefore differ where related irises grow nearby.

Give it moist soil that lets excess water drain away. Sandy soil and loam both suit its needs. It accepts mildly acid to neutral soil. PFAF also specifies soil free of lime. Grow it in full sun or light shade. It can grow well near water where drainage remains good. Its source matters when judging its ability to survive winter. Some populations do not prove hardy in Britain. The evidence gives no single hardiness zone for this species.

Avoid needless disturbance to the roots once plants have settled. PFAF names early September as a suitable time for moving. It also describes division after flowering as a means of propagation. Large divisions can go straight into their final sites. Keep smaller pieces in pots until they form sound roots. Sow fresh seed in a cold frame when ripe. Raise seedlings under cover through their first year. Set them out in late spring or early summer.

The leaves provide fibre for cord, rope, and paper. Indigenous North Americans used selected fibres from the leaf edges. Processing the leaves can also yield pale tan paper. PFAF records no known food use for this plant. It reports a traditional root use to hasten childbirth. This record does not establish safety for home treatment. The supplied evidence gives no species-specific account of pests or diseases.