As I understand it, the colder and longer your winter the smaller the rhizome.

Makes sense when you think of it in terms of growing season length.

Some of my best iris came from a midwest grower --- shriveled tiny things. But they performed as well as later larger ones.

It does make a big difference how cold your winter is. I've received monsters from trades further south. It does make a difference on the iris itself. Some of my tall bearded just don't grow as big as others, but it makes no difference on how well they bloom. You like to receive nice big rhizomes, but they aren't guaranteed to produce the best blooms.

thanks to both of you for responding and sharing. Ive had my Iris for many years and they do produce tall beautiful blooms... I guess mine simply have smaller rhizomes. Plus, I have no idea what kind I received (just that they are white with orange beard)...

ngraham... Im glad you stated that some of your tall bearded just don't grow as big as others. It's put my mind at ease about the trade.

Im still open to others comments for the sake of learning your experiences with Iris... thanks again!

Love GardenWeb peeps! :o)

Soil fertility and summer water can affect size as well. My last garden had rich soil and was small enough to ensure good summer watering. I had huge gorgeous rhizomes to share. My new garden is sand and rock and there's never enough time to water everything consistently. And now I get alot of small rhizomes and little increase. I try to send extra fans when I can to make up for the small size. Personally I never care what size the rhizomes I receive are as I have been growing them long enough to know that they'll get big eventually. Hopefully your trading partner is also realistic in their expectations.

BTW, I just got a box from the midwest of HUGE rhizomes. An unexpected surprise.

Mike