Bearded iris enjoy a position of full sun. Avoid crowding them with other plants as the rhizome needs to be backed by the sun to encourage flowers. For this reason you often find a bed dedicated to just iris.
They’ll grow well in a neutral, well-drained soil. A south-facing border with the protection of wall is ideal.
Bearded iris can be planted in autumn or spring. If you've bought potted plants, make sure they're planted at the same depth as they were in the pot. If purchased as a bare rhizome, soak the rhizome in water for a few minutes before planting.
If planting in a poorly-drained soil, dig in some horticultural grit to improve drainage. Plant so the top of the rhizome is just above the soil surface. Position the rhizome facing south if possible. Water plants in well.
Divide bearded iris every third year for the good of the parent plant and to create more plants. The heart of a mature iris can become woody and unproductive after a few years.
After flowering lift the rhizome with a garden fork. Cut off the healthy, young rhizomes at the edge of the plant and discard the woody centre. Replant the new plants immediately and cut back the foliage to about 12cm. This prevents the plants from being rocked about in the wind.
Bearded iris can suffer from rhizome rot. As with all rotting things, the rhizome will start to smell and the base of the leaves will turn yellow. You may not spot the problem until you see foliage collapsed on the ground. The best way to cure this fungal problem is to cut out and discard sections of the affected growth. The problem tends to be worse in humid and hot conditions.
Bearded iris can also be affected by iris leaf spot, a fungal disease. Fungal spores are easily spread in wet weather and enter through damaged leaves. Minimise the risk by clearing away leaf debris from around plants, and avoid damaging leaves and stems unnecessarily.
After flowering, deadhead plants as you may be lucky and get a second flush. In autumn tidy up the evergreen foliage by trimming it back to about 15cm.
Keep iris beds well weeded as shading from weeds will not be beneficial. Feed plants with a general purpose fertiliser in spring.
Divide plants every third year.