Whilst irises prefer a soil high in clay  this is not entirely practical for the pond as it can lead to excessive nutrients and exacerbate algal blooms, so lower nutrient aquatic soil or garden sub-soil would be best, supplemented with feeding from slow release fertiliser tablets in the spring.

Irises are best planted in pots that are wide and shallow as the rhizomes grow in a more of less straight line close to the surface of the soil.  When planting in a basket the rhizome should be planted at the edge with the growing tip pointing towards the centre to maximise the pot’s space.  Young plants with no top growth should be planted with the rhizome horizontal underneath the surface of the soil and the growing tip barely below the surface