How to plant iris bulbs
Plant miniature irises close together in a container to make a bright display. Choose a wide, shallow container to show off the delicate blooms in spring. Use a free draining, peat-free potting mix with plenty of horticultural grit. Plant your miniature Iris reticulata bulbs 15cm below the soil surface, leaving 5cm between bulbs. Water the bulbs in well, and place your containers in a sunny spot. Cover the soil with decorative gravel to protect moisture and make your pots look neat and tidy.
Larger bearded iris types prefer to have their rhizomes much closer to the soil surface so that they are almost visible. Plant your bearded irises in very free draining soil at the edge or middle of a border where they’re best appreciated in flower. Make sure your chosen spot is weed-free and never floods – irises won’t tolerate flooding. You don’t need to feed your irises, just lightly mulch around the rhizomes at the beginning of summer with well-rotted manure or compost.
When to plant irises
Plant your miniature iris bulbs in autumn between September and October. They’re hardy characters so keep the planted containers in a sheltered spot outdoors through the winter months. Move them into a prominent position in spring when you start to see shoots appear to enjoy the delicate blooms when they arrive.
Plant bearded irises at the end of summer and into the beginning of autumn. Give the rhizomes a soak for an hour before you plant them shallowly into the border or into pots.
Do iris bulbs multiply?
Iris bulbs do multiply over time. Gently lift your bulbs every few years and pull the clumps of new and old bulbs apart to space out in the ground. Do the same for your pot-grown miniature iris bulbs, or dig them up to store over the summer after the leaves and flowers have died back in summer to reuse the pot. Space out the bulbs when you come to plant them in autumn again.
Reblooming bearded iris varieties have a fast growth rate, producing two flushes of flowers during the year. Their fast growth rate means that the clumps expand year after year and require splitting to keep them healthy. After the last flush of flowers in summer, lift your iris clump using a fork and divide it into pieces. Ensure that each section of rhizome has roots and a fan of leaves attached. Share these new little iris plants with friends, or plant them around the border for even more colour come summer.