With all rhizomatous irises, both bearded and beardless, each individual rhizome will only bloom once in its lifetime. In most cases, the rhizome also grows additional rhizomes (increases) along its sides. Once those increases grow to maturity, they bloom and grow more increases. That's how a single rhizome becomes a clump over the course of a year or two. Of course a clump can be divided any time, and the individual rhizomes planted separately to grow into their own clumps.

Occasionally, a rhizome will bloom and not grow any increases. That is a condition known as bloomout and will result in loss of the plant. Fortunately, that doesn't happen often.

Does that answer your questions?

Laurie

Hi Carla,

Siberians usually bloom once each year, but there is work with repeat bloomers going on around the country. I remember reading an article a little while ago (I believe by Terry Aitken) about rebloom being affected by maintaining a cooler (?) soil temperature (it's been a while since I read it). The Hollingworth's here in Michigan just introduced a SIB they said was their most reliable for repeat/rebloom but I can't recall the name right now.

Yes SIB's do increase like other irises, by additional fans growing from the mother plant and by setting seed. It used to be common for a them to grow outward in a ring leaving a bare spot in the center of the clump, but this is something breeders have been working to fix.

Don't forget the other beardless iris. There are many beardless species, spurias, louisianas, japanese, pseudatas (the gorgeous "eyelash" irises), laevigatas, and even pseudacorus hybrids (but these are invasive for some).

There is a huge variety of iris to choose from. The only limit will be your time, money and space not the amount of diversity available.

Brock

Thank you both.
Brock, thanks for the extra info. My addictions have spread to other plants. I have gathered quite a few vendor's names that sell iris. I realized that now is not the time to get the "hot" or popular selections but will have choices to pour over in the heat this summer. I have memories of my grandmother growing iris. Wish I had those now.

Carla

Carla,

An ever-helpful friend of mine (from my iris club) asked if I could share this with you:

"Some of the Hollingworth Siberians with a tendancy towards rebloom are:
CORONATION ANTHEM (1990)
HELIOTROPE BOUQUET (1986)
HELLO YELLOW (1999)
LAVENDER FAIR (2000)
LIGHT OF HEART (2007)
SEE YA LATER (2006) Catalog: "One of our most reliable repeat bloomers."
SMILEY FACE (2004)
WINDWOOD SPRING (1985)"

'See Ya Later' must have been the one I was thinking of. I wrote it down during judges' training, but have since misplaced my notes.

Also, if you would like to grow irises like your grandmother's you could try looking into the Historic Iris Preservation Society's list of sources. The historics (anything older than 30 years old) are still around for a reason and deserve space in any garden.

Brock

Thank you Brock. You've been very helpful.

Carla

You're most welcome Carla. It's always nice to learn that my ramblings have helped someone. I'm not much of a seasoned iris veteran (8 or 9 years now(I think)), but I'll gladly offer what I do know. I'm sure my friend will be happy to see the information will be put to good use.

Brock

I would call Coronation Anthem an instant rebloomer. The additional flowers come shortly after the main blooming time here in Denmark.