Caring for Reticulated Iris

Reticulated iris is a low-maintenance bulb once established, but getting the watering regime right is essential. These bulbs need moisture in autumn and winter as they develop roots, and again in early spring as they flower. However, they must have a dry dormancy period from late spring through summer. Water sparingly after planting in autumn if conditions are dry, but natural rainfall is usually sufficient through winter. Avoid watering from late May onwards—wet summer conditions encourage bulb rot. If you grow them in pots, move containers under cover or tip them on their side after the foliage dies back to keep them dry. Feed once in early spring, ideally in March, just as the shoots emerge. Use a low-nitrogen, high-potash fertiliser such as a tomato feed diluted to half strength, or scatter a light dressing of bone meal around the clumps. Avoid high-nitrogen feeds, which promote soft leaf growth at the expense of flowers. Don't feed after flowering; the bulbs need to harden off for dormancy. Reticulated iris is hardy to zone 5a, so winter protection isn't needed in temperate Europe. The main pest problem is iris ink disease, a fungal condition causing black blotches on the bulbs and stunted growth. Lift and destroy affected bulbs immediately and avoid replanting irises in the same spot. Narcissus bulb fly larvae occasionally tunnel into the bulbs; if you notice soft, damaged bulbs at planting time, discard them. Slugs may nibble emerging shoots in early spring—scatter slug pellets or use barriers if damage is severe. Mulching isn't recommended, as it can trap moisture around the bulbs and increase the risk of rot.