Irises: A scary story and a question., 1 by GreenThumbsTN

GreenThumbsTN wrote:
anita,

your iris will multiply. they do not 'take over the yard' in the sense that they spread by underground roots like ivy and vinca or free seed like kudzu or nandina.
the main fat part (rhizome) of the iris will bloom and then it's 'done', not to ever bloom again. it will send out shoots on the sides which will become the flowering rhizomes for next season.

an iris will bloom the same color every year, they do not 'become all white or purple'. however, some varieties are particularly proliferative and will have 10 or more babies per year while some other varieties may only have 1 or two. so if one does not clean the beds by removing the old mothers and replanting the babies every so often (every three or so years is sufficient for most gardens),it is possible that the faster spreading variety can overtake the slower ones and the slower ones can rot or die. iris rhizomes, when not divided will grow on top of each other, i have seen them as thick as 3 or 4 stacked with the bottom ones hollow and dead.

here is a picture of how rhizomes look in the spring when they have made babies, you can see the one in the middle made a lot more than the one on the left side. the center, fat portion is the part that will bloom this year, the sides will become fat by september and each baby on the side will look like its mother by next spring:



This message was edited Mar 2, 2009 9:21 AM

editing to remove typos.

This message was edited Mar 2, 2009 9:22 AM