Iris

Q. I live in St. Louis Missouri and I moved into an older home 2 years ago that has bunches and bunches and bunches of crowded iris plants. These iris have never bloomed since I've been here and the green leaves of the iris look about 1/2 - 3/4 fully grown now. My question is: Can I thin them out now at this time of year and replant them? And just how do I thin them out and how deep do I replant them? I've never had iris before. Thanks for your help!

A. This is an unfortunate time to be considering such action but as you say they have never bloomed so what have you to lose? The iris have been neglected by the past owner [maybe they didn't like flowers...what?] So here is what to do:

Start at one end and using a good spade dig around the green stems keeping in mind that the rhizomes underneath are spreading out a ways so do not cut in too close or you will slice into them. Make a wide circle around a group lift them out and lay on paper or plastic. Only dig out as much as you will handle that day.

Gently shake off some soil and observe where the underground growths have separations. Break them apart so that all the new plants have roots and foliage. If a couple small ones are joined do not worry...leave them until the fall or next year. Be sure to separate mainly the large ones which are joined.

Replant into the bed which you have worked up with additions of dried compost or any organic material you have or buy. Space them 8 inches apart having the rhizome just below the soil line. Planting too deep will give you absolutely no flowers. That is the key to success with iris! In the future please do this task in late summer early fall so that you do not interfere with the spring flowering.

Q. I have some bearded iris that look healthy with great green leaves but no blooms. They have never bloomed in 6 or 7 years. They get a lot of sun but I don't fertilize them at all. I think this maybe the problem. The soil is sandy and doesn't hold much water either. Is fertilizing my problem? What would be a good fertilizer to use?

A. I have two ideas for you:

One is the depth of the rhizomes in the soil. Did you know if you plant them down into the soil that the irises will not bloom? Right!

The tops should be right at the soil surface. You can cover with a bit of soil or mulch to protect them from the sun rays but do not have them completely down into the soil. The roots grow down and collect the needed moisture and food. If you planted them maybe 2-4" deep they will not produce flowers unless the top soil erodes and the rhizomes are at the surface. Strange but true.

You know number two: Fertilize!

Plants are just like animals in that they need food to live and grow. I want you to start a regular fertilizing program with not only your iris but all the plants you are growing inside and out. Buy a good food from a garden center like Scotts Peters Rapid Grow or Miracle-Gro. They all supply what plants need to produce good foliage and flowers. Sprinkle some bone meal around the iris now give them food every three weeks until the coolness of fall sets in.

In the spring just as the tiny sprouts are seen pushing up start feeding again every two weeks until the flowering is over.

Q. Do I need to deadhead my irises? And when?

A. All your iris should have been cut back by now [mid-July]. Here is what I want you to do:

Take very sharp and clean shears and cut the flower stems right back into the foliage. Do not remove the leaves.