How to plant and grow iris

We plant lots of iris bulbs at Perch Hill to start off a long bulb flower succession. They're beautiful and successful in pots, at the front of borders, or in grass.


Soil and Site

Full sun in well drained soil – for maximum flower set, iris rhizomes need to be warmed by the sun in August and September.


Iris (bearded), plant 30cm apart.

Iris reticulata and Iris histroides, plant 7cm (3in) deep and 10cm (4in) apart.

In the garden

Plant bearded iris with the upper part of the rhizome partially exposed to get a summer baking, particularly important in August and September to bake the rhizomes ready for next year’s flowers. If the soil is unsuitable – heavy clay – growing in raised beds may be successful.

For containers

Iris reticulata and Iris histroides are lovely in pots for the house (out of reach of marauding sparrows which tend to pick at their flowers) and will be in flower in February forced on a sunny windowsill. Once in flower, it’s essential to keep them cool or they go over in 4 or 5 days. Kept cool, you should triple this flower life.


Avoid overcrowding of plants as this shades the rhizomes, meaning fewer flowers. When clumps become congested divide every three to five years, six weeks after flowering – around the end of August – in order for the plants to establish before winter. The rhizomes grow outwards, so clear the centre of the plant to remove the oldest parts.

Remove dying foliage in the autumn.

Cut Flowers

Stand in deep water after cutting. Remove fading flowers and buds will continue to emerge.