Common Name: Siberian Iris
They are quite hardy and will grow in full sun or shade in soils ranging from the heaviest clay to the lightest sandy soil, but prefer moist well-drained, acid to neutral soil.
Plants grow can grow to 1200mm (4ft) high with a spread of around 300-600mm (1-2ft) and mid-blue to violet-blue flowers appear in late spring to early summer.
They require minimal aftercare, and are generally disease free and untroubled by pests such as Deer and Rabbits.
They are also useful in coastal districts due to their tolerance to salt.
Iris sibirica seed heads can look good in winter covered in hoare frost, so consider not chopping them down after flowering.
Division: Plants can be propagated by dividing the rhizome (horizontal underground stem) from July to September.
Seed: The flowers are hermaphroditic (have both male and female organs) and are pollinated by insects, thus making the plants capable of self-fertilisation.
Once the seeds have ripened, generally between August and September, they should be collected and dried ready for propagation.
Anytime between Week 45 to Week 13 sow the seeds* in trays of seed compost and germinate at a temperature of around 18°-21°C (65°-70°F) for 2-4 weeks.
Then remove them from these temperatures and subject them to a temperature of around -4°to + 4°C (25°-40°F) for another 4-6 weeks.
After this cooling period raise the temperature to 5°-10°C (40°-50°F)
The use of a cold greenhouse or coldframe during these processes is ideal.
*Prior to sowing the seeds abrade the hard seeds with a piece of sand paper, or nick the surface with a knife to assist moisture penetration.
Germination usually takes around 8-10 weeks.
When seedling are large enough to handle prick them out into individual 75mm (3") pots and grow on in the cold frame or a cold greenhouse until planting out time.
Plant out 500-600mm (18"-24") apart around week 40 or grow on in a coldframe until around week 13 the following year.