How to Fertilize Siberian iris 'Summer Sky'?
Diluted iris bulb feed every three to four weeks spring blooming season

Siberian iris 'Summer Sky' · Iris 'Summer Sky'
Grow in any good garden soil that is preferably moist but not waterlogged. In drier soils, dig in well-rotted organic matter before planting then apply as a mulch each spring
Diluted iris bulb feed every three to four weeks spring blooming season