Expert: Long Island Gardener - 11/19/2006

Question
I had to divide some irises. I planted some as the ground has not frozen as yet. What is the best way to story the remainder? Also, can I keep on planting until the soil freezes? I love in Zone 7.

Answer
I'm afraid you'll have to win Beat The Clock on this one.

Iris Rhizomes may look tough.  But they can't take much time out of the ground.  Get as many of those babies as you can in the ground as fast as possible.

Don't water them in - Mother Nature will take care of this.  The cold temps and moisture spell water torture for these.  A generous mulching of leaves will soften the recovery period when spring arrives.

For any that don't make it back to Earth before the hard freeze, get them into clay pots packed with rich garden soil and store them in a very cool basement or garage.

The trick is to keep them cool, but not frozen.

The best carryover will be to pot them up asap and keep them, unfrozen, until spring thaw.  Don't fertilize and don't forget to water from time to time, just a little, while these are in storage.

In a perfect world, you would move the cycle seamlessly as possible right through spring, when growth has resumed, so that you don't miss the flowering cycle.  These won't have the advantage of strong root development before a deep solid freeze is here.  For the unlucky Irises planted last, don't be surprised they take a year or longer to bloom again.  They will need some generous doses of Bone Meal to reinforce new roots.

North Dakota State University devotes a full webpage to the subject of Irises (www.ext.nodak.edu/extpubs/plantsci/landscap/h113w.htm).  Have a peek.

Keep in touch.  Let me know how things go.  And good luck.