by Jim Murrain
Iris cristata, the Dwarf Crested Iris, is native to much of the eastern half of the USA. It is represented in the north by its smaller cousin Iris lacustris, the Dwarf Lake Iris. I. cristata prefers good drainage and open woodlands. It is most at home in the Appalachian, Ozark, and Ouachita mountains ranges where it can be seen flowering by the thousands.
Even though it wants good drainage it is often seen along stream sides and even growing in the rocky bed of a shallow rill. It quickly forms dense clumps in a garden where it is most happy on a north facing slope. It also does well on the north side of a house as long as it gets bright light.
Iris cristata is usually seen in shades of blue and lavender but white flowered forms are not rare.
My biggest challenge to growing this Iris is the occasional drought. While demanding good drainage it also needs a reliable supply of moisture. It is a tough little Iris and can survive typical summer dryness but must have supplemental water when rains fail outside of its native range.
There are no known hybrids between I. cristata and other species.
There have been rumors for many decades of pink flowered forms but none have made it into cultivation. That would be a worthwhile contribution to horticulture.
Hardiness is claimed for USDA zones 3 to 9 but 5 to 8 are more likely. I'm curious who grows the Dwarf Crested Iris outside its native range. Is it easy or has it become a diva when far from home?