Plant in full sun with regular to occasional irrigation. It has proven to be heat and cold tolerant and cold hardy to at least 10° F. This familiar plant is found in old home sites throughout America and is amongst the earliest of the irises to flower.

Iris 'Grandma's Purple Flag' is fondly referred to just as "Grandma's Purple" and is also known as Traditional Purple or Unknown purple and is often listed as a Iris germanica variety. It is an old variety that has long been in cultivation in California gardens and its parentage and original source seems lost, but there is some speculation that it is the same as 'Crimson King', a hybrid introduced in 1893 that was credited to British nurseryman Peter Barr, founder of Barr & Sons Nursery. We have grown this great attractive and durable plant since getting it in 2001 from John Schoustra of Greenwood Nursery in Somis, California and we thank John for introducing this great iris to us. 

This information about Iris 'Grandma's Purple Flag' displayed is based on research conducted in our horticultural library and from reliable online resources. We also will relate observations made about it as it grows in our nursery gardens and other gardens we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments that we receive from others and we welcome hearing from anyone with additional information, particularly if they can share any cultural information that would aid others in growing it.