when to divide Sibs and PCIs in the PNW?

[PNWJudy]

Hi Mike et al.

I need to divide / move /pot up my siberians that do not bloom well, likely because of too much dry shade.
I also have some PCIs that I want to get a few divisions from the edges to have for trades.

I also have Iris orientalis and a few that have kind of rhizomes along the ground similar to the yellow iris that grows near ponds.
I suspect mine do not bloom well again because of too dry and too shady. So I should get them out, too. I do like the tall foliage as accent where they are, but I may as well get some bloom if I can.

I don't have a place to plant them yet--always renovating!
So I will be potting up the plants for now and not replanting.
Do I put any root hormone in? Any fertilizer?
So any tips on timing and the best potting medium and care while in pots is really appreciated.

Thanks so much,
Judy



I

[Garden_of_Mu]

Hi Judy - Sorry for the delay.

Please do not touch your PCIs now. They are VERY picky about division and it must be done in either spring or fall when new white roots are growing out for success. Any other time will kill them. Siberiens are best done in early spring if splitting them up, if just moving a clump do it anytime but give them lots of water until reestablished.

I am not very familiar with the needs of the spuria family so can't help with orientalis (you do mean the tall white and yellow one with the horizontal form that the ants love, right?). A good iris for dry shade is i. foetidissima (don't worry, the name refers to the smell of the crushed leaves, not the flower).