Divide and replant your Japanese iris in the fall every three or four years to keep them healthy and blooming at their best.

Replant irises in groups about 30cm (1ft) apart, with the rhizome just below the surface. Firm soil around roots and water well.

Starting around the turn of the 20th century, iris enthusiasts began to be active in the area, seeking out wild specimens in the region's swamps to document, transplant and cultivate. The iris ...