It’s the best time of year to tidy up and propagate iris rhizomes, says Kris
Keep roots moist by carrying out the process early or late in the day, or do the job in the shade
1) Shake the lifted clump to remove loose soil, then use secateurs or a sharp knife to cut away 2-3in (5-7.5cm) sections of rhizome, making sure each divided section retains one fan of healthy foliage.
2) It may be necessary to wash the rhizome sections to reveal their roots – simply pulling away the clumps of earth risks damaging the finer roots. Once revealed, reduce straggly roots by a third.
3) With roots reduced it’s time to cut back top growth. Cut each strappy leaf blade down to 6in (15cm) or so. This will prevent windrock and concentrate energy on new root growth for better establishment.
4) Your iris divisions are now ready to plant out. Position them at least 5in (12.5cm) apart in a sunny border. Fan out the finer roots and set the rhizome so the upper half is above ground. Firm in and water.