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. 

The information displayed on this page about Iris 'Grandma's Purple Flag' is based on our research conducted about this plant from books in our nursery library as well as from information that is provided by reliable online resources. We also have included our own observations made about it as it grew in the nursery gardens and other gardens visited, as well how the crops of this plant performed in the containers when we had them in our nursery field. We also include comments received from others and welcome hearing from anyone who has information about this plant, particularly if it includes cultural information aiding others to better grow it.