Iris Dividing Time

I got this email today thought I would share it for those of you in the South who need to divide your iris.

Last Chance to Divide Your Bearded Irises this Year!

Rules were meant to be broken, and there´s one that many of us gardeners here in the hot, droughty Southeast have deliberately "stretched" this year:

Always divide your Bearded Irises between Independence Day and Labor Day.

Most of us have either decided it´s too hot to do any serious garden work, period, or we´ve been so terrified by the size of our water bill that we didn´t dare risk the two weeks of heavy watering that newly-divided Irises need. (Then of course, there are those rare, honest gardeners who will tell you they simply forgot!) At any rate, if you noticed your Beardeds looking rather threadbare this year, or if it´s been 4 years or more since you planted them, you may want to divide them this year. The time to do it is right now. Here´s how:

1.
This giant clump of Iris Beverly Sills hadn´t been divided in 6 years, so it came up a tangled weave of rhizomes and roots!
As always with transplanting, try to have all the planting sites ready before you dig up the first plant. This is more important when dividing mature plants than when planting new ones -- after all, the new guys are potted up already, and you can always bung them into the shade with a good dose of water and forget about them for a few days. Not so with Iris rhizomes (fancy term for "bulbs") that already have roots and leaves and are either moving from one home to another or getting thinned and replanted in the same -- yet nicely enriched -- home. Think of the actual division and replanting process as occupying minutes per plant, not hours. I´d even advise doing them one by one -- that is, digging up one, dividing it, replanting the clumps, then digging up another, etc. -- if the day is hot and dry.

So before you begin digging, take a good look at your Irises. A nicely overgrown clump can yield anywhere from two to a dozen or more new plants. Do you want to set them all in the existing Iris planting, branch out to new parts of the garden, or tuck them here and there as accents?
2.
After gently rinsing the soil loose, the clump fell into 10 or 11 pieces all by itself! Iris is very obliging about doing some of the dividing for you!
Dig any new holes you think you´ll need, loosening the soil to 10 inches deep and 12 inches wide. Then fill it back in, heavily enriching it with compost and other amendments. Irises are heavy feeders, so be sure to save plenty of compost, manure, etc., for your original planting sites -- you´re going to enrich them before re-planting the clumps! Finally, leave only a shallow, sloping hole in the new sites. The hole should be 5 inches deep at its deepest point, rising to a little ridge about 2 inches wide, then sloping back down on the other side of the ridge to 5 inches deep. The ridge is where you set the rhizome, with the roots plunging down the 5-inch slopes on either side. The ridge should be no more than 1 inch below soil level. Mercifully, Irises like shallow planting!

If you have enough clumps to plan new designs with the divisions you will be harvesting, space the new planting sites at least 8 inches apart, to give the plants a few years to grow before they once again become too large and clumpy!
3. Right before you divide the Irises, get out your compost, a sharp knife, a shovel or trowel, and turn on the hose. You´re ready to begin!
4. Dig up your Irises with a generous hand, remembering that although the rhizome is just an inch below soil level, the long, thick roots extend a good ways down and out from the plant. Once you have the whole plant (and probably a big hunk of soil) aboveground, quickly hose it down so that you can see what you´re doing. If the clump is hugely overgrown, several rhizomes will obligingly fall off during the hosing process. Be careful not to spray the water so hard that you snap the rhizomes, however.
Cut the rhizomes apart at the joint between the old rhizome and its new offshoots. If the old rhizome is nearly rootless (like the one in this photo), discard it. Otherwise, replant it along with the new growth.




Trim the foliage from the rhizomes and plant them along a ridge of soil, fanning the roots down into the holes on either side of the ridge. In this case I kept one offshoot rhizome attached to the original, but another cut could have been made at the joint between the two if more divisions were wanted. Now just cover all but the very top of the rhizomes with soil, pat it down firmly, and water well!

5. When the soil has been washed free, what you will see is a tangle of new and old rhizomes, many with side-shoots and new buds, all with twisted roots going every which way. Iris rhizomes spread horizontally, so you´ll have a long, plump rhizome, a thinner part joining it to the next plump rhizome, etc., all with side shoots. You want to cut, swiftly and firmly (slicing rather than sawing), in the narrow part between rhizomes. You´ll inevitably slice through a few roots; just do it, rather than trying to untangle and separate them.

Be sure you get one entire rhizome, either with new buds or side-shoots, with every division. If you find a part that is discolored, soft, or rootless, discard it. And if you want larger divisions, keep more than one rhizome in every division. Larger divisions look less sparse in the garden that first year, but smaller divisions tend to take off better, so the choice is really yours!

6. Trim the leaves of each division. This is really a water-saving measure more than anything, but it´s also useful if your plant has been bothered by any sort of leaf disease. The rhizome doesn´t need much top-growth to re-establish, so leave anywhere from half to just a few inches of the foliage on the divisions.
7. Transplant the newly-shorn divisions in your prepared holes, lining up the rhizomes along the ridge, fanning the roots down on either side into the sloping holes, and covering the rhizomes leaving the top of the rhizomes visible aboveground. Water the transplants in well.
8. Return to the original planting sites, add your manure or other amendments, and repeat the ridge-building, rhizome-setting process. Water in well.

For the first two weeks after transplanting, water your Irises scrupulously. With any luck, the fall weather will arrive and help you out. If too much fall arrives, however -- and the temperature drops alarmingly -- just mulch more heavily around the plants. Bearded Irises are very tough, and if you´ve given them a rich, moist home in well-worked soil, they´ll do their best to settle right in before winter!

If all of this sounds very do-able but you´ve never grown Bearded Irises before, fall is perfect planting time for new rhizomes, and now you know just how to do it! Here are some of my very highest recommendations for a rainbow of Iris:

Solid colors (best for a large planting):

Skier´s Delight is a multiple award-winner for its massive 6-inch blooms of pure white, arising 9 per stem on very well-branched plants.

Beverly Sills is the classic soft pink, with ruffled petals and a free-blooming nature you´ll love. Winner of the Dykes Medal, the highest honor in the Iris world!

Dusky Challenger has the richest, deepest purple blooms I´ve ever grown. A full 6 inches across, they arise 4 per stem. Another Dykes Medal Winner!

Play with Fire is the closest thing yet to a red Iris ? this one a deep, smoldering burgundy on very prolific stems.

Hello Darkness is my favorite black, a smoky bloom with a velvety texture!

Multicolored (irresistible for accent plantings and cutflowers):

Bride´s Halo is the Iris that wanted to be a Daffodil. White with generous yellow edging, it hearkens back to the early spring garden!

Conjuration is so loaded down with awards it´s a wonder it can hold up its stems! Hardy through zone 9 (most other Beardeds like to stay in zones 3-8), it sports up to a dozen blooms on every stem. And the color is magnificent ? shading from deep purple at the petal tips to mauve to pure white at the base, set off by a tiny orange beard.

Queen of Hearts is a heavily fringed, coral-toned bloom with white falls edged in coral. Very unusual colors! It´s hardy in zones 4-9.

Magic Man is a brilliant beauty, with mauve-to-lilac standards, deep purple falls, and glowing golden beards to highlight them both!

Change of Pace is really stunning, with pale pink standards set off by deep golden signals, and white falls heavily outlined in deep lavender, with lavender freckles dotting the white! Hardy from zones 3-9, it´s a must-have for cutflowers or the garden.

And if you´re still looking for something to divide in the garden right now, before fall planting takes you over? Many spring- and summer-blooming bulbs are ripe for division, from Allium to Grape Hyacinth to Crocus to Daffodils! How nice to make new plants instead of buying them, and to fill your garden with ready-to-colonize, easy-to-divide bulbs!

Thanks! My MIL has been after me since July to divide her irises, and I was secretly hoping to be able to say it was too late this year, lolol. :) Guess I better get a move on, huh?

It really is too late, unless of course those extra divisions need new homes... September 15 is the absolute latest (yesterday) here, but another week or two for TN sounds right... John

WE have had such a drought here, that I think extending it some now that we have rain won't hurt too much :-) At least that's what I hope!

donna

heres my question-anyone got any extras!??!! im always looking for Iris's!
thanks in advance
dori-iris crazy!

This message was edited Sunday, Sep 22nd 2:32 PM