Ideal time to divide and transplant iris is....?

I want to divide and send some bearded irises to my sister in Ohio.
What's the best time of year to do this?

They go dormant in the Summer, so that is the best time. Usually 6-8 weeks after bloom is safe.

At my place we try to wait a full 6 weeks but figure 4 weeks to be sufficient following the normal bloom period. For us it's dig and share in July and label/plant in August.

Roni

In my short season climate, I dig as soon as bloom is finished. What's most important is getting the irises to your sister so she can get them in the ground AT LEAST 6 weeks before her first frost of fall.

Laurie

I moved into my current residence last August. An iris bed was already established. I've never grown irises, so I really don't know this for sure...but they look awfully crowded. Just a few irises bloomed during the first two or three weeks of April. I haven't had any blooms in atleast two weeks. Do you think they're done blooming? Do you think it would be okay to divide them now? Does crowding have anything to do with how much they bloom?

johnnyswife,

If the irises in other gardens in your area have already finished blooming, I'd say your bloom season is finished. Overcrowding is a common cause of non-bloom in bearded irises. You can see other potential causes in my FAQ on my website at:

http://www.angelfire.com/mn3/shadowood/irisfaq.html

I'm not at all acquainted with your area, so I'll let the other OK folks advise you on optimal timing for dividing your irises.

Laurie

I'm dying to divide some of my tall bearded but making myself wait those 4-6 weeks for the new divisions to gain size. Plan to divide in June sometime.

While I have everyone's attention, I might as well ask about another aspect of iris cultivation. It seems to me I always plant irises either too deep or too shallow. Can anyone post a link to a good diagram or photo which would help me with this?

missgarney,

There is some "wiggle room" where it comes to planting depth, depending on your specific climatic and growing conditions, and the preferences of the specific iris types and cultivars planted.

If you're asking about bearded irises, the rule of thumb is to plant them with the tops of the rhizomes level with the soil surface. However, I tend to cover mine with less than 1/2" of light soil or sand as a bit of added protection against my severe northern temps and to help discourage frost heaving. I have read recommendations that they should be covered lightly in hot desert climates to protect them from frying in the sun, as well. As long as they are not buried more than 1/2-1" deep, they should be able to bloom well. Any deeper than that and they may refuse to bloom at all.

Irises will also tend to adjust their own planting depth over time. I have irises that like to rise up on top of the soil, and I have others that like to dig themselves down deeper. I figure they know best, so I don't adjust the ones that have found their own places in the soil.

Laurie

I have to leave the tops of my tall bearded exposed or they dont seem to bloom well here. I plant them with the tops of the rhizome barely covered and then when it rains or I water the top become exposed.

charlotte