Iris pseudacorus

Split the irises every year, immediately after flowering has ended. At this point the early summer leaves and flower stems have started to die back, and the late summer leaves have started to grow. Split individual plants with a light spade, leaving the part to be retained undisturbed in the soil. Remove about 30-50% of the total plant mass. The aim is to leave plants about the size that would fit under an A5 sheet of paper. After splitting, cut back the early-summer leaves on the remaining plants, and cut or break off the flower stems. Finally, top-dress the plants.

Ideally the Iris plant would need to be planted in a sunny spot so that it can receive at least six hours of sun a day as well as being planted in well drained but moist soil. They do well near water but should be at least 6 inches above water level. Avoid hoeing around the base of the plants as the roots are near the surface and easily damaged. Plenty of mulch can help avoid weed growth around them, although rhizomatous varieties should not be mulched, as this could rot the rhizomes.

The bulbs should be planted in late Summer or Autumn, and only about 2in deep. Great care must be taken when planting this iris not to damage the fleshy roots. Add coarse grit and bone meal before planting.