By Jim Hedgecock
It is 60 degrees outside and it is December 4th. That temperature is 20 degrees above normal and on the news this morning, the weather forecaster said 425 cities set new high records yesterday. I don't remember the exact number of states that are affected, but a large number of midwest and southern states are in what appears to be one of the worst, if not the worst, drought ever. Here in northern Missouri, we have had less than 15 inches of rain this year and our normal totals are in the high 30's. There just is not any sign of relief in the near future.
The question we are getting from our customers is, "What can I do for my irises in this drought and will they be okay?" If you have raised irises for any length of time, you know that in most instances, they are pretty resilient and they will do just fine in drought conditions. There are, however, some things you can do to help them make it through this winter and next spring.
If you are growing the bearded irises and spuria irises, and you set out new irises or transplanted some of your own irises, it would be wise to water your new irises a couple of times a month if you are not getting any moisture. We set out irises in late September and again in October and they have had virtually no moisture at this point in time. The irises are not dead, but I hold little hope for any bloom on these irises and I am sure increase will be poor compared to normal years with more moisture. (We don't have a way to water our 14 acres of irises and couldn't afford it if we could.)
My other fear for newly planted irises is heaving. I can walk out in our fields right now and pull up just about any newly planted rhizome. The moisture that we would normally receive would have helped the rhizomes to root better than they have. That sets the rhizomes up for heaving (coming out of the ground) if you live in a state that has lots of freezes and thaws. A mulch in the fall will stop heaving and it insulates the newly planted rhizomes from the cold. The one drawback is that it also holds moisture. This is a double-edged sword. It will be good for the rhizomes to hold in moisture this winter if there is little rain. But if we get good spring rains, mulch will be a curse if it is not removed when the spring temps reach the 50's or higher because of bacterial and fungal growth.
So what is a good mulch? Straw is excellent. Wheat straw tends to volunteer wheat in your iris beds. I prefer oat straw when I can get it. Oats do not volunteer nearly as bad as wheat. Of course there are other alternatives. I know some people use pine needles and even leaves. The important thing here again is removal when the temps warm up in the spring.
If you are raising water irises, proper moisture is much more critical. We nearly lost a large number of our Louisianas this fall because we got busy and did not keep them watered. Many of the rhizomes had popped right out of the dry soil and were nearly dead. Thankfully, we caught it in time and we added new soil on top of the rhizomes and watered the rhizomes deeply several times and they are looking great.
In closing, I would say the drought will probably affect bloom a bit if more moisture doesn't come our way by spring, but a little extra watering this fall and winter will go a long way toward keeping your irises in good condition.
God Bless you and your gardens and have a great Holiday season.