Mother Earth and Superstition vs. Black Walnut

are black walnuts toxic to irises? This is the second year in a row our irises (ok our only efforts with them) have ended in disapointment. of the 10 we planted the last 4 in the bed at to end nearest the walnut.. either turned to mush or came up and only grow a few inches and died. The ones in the other end of the bed look like they might be our first irises to survive more then a year.. althought no blooms this year.. folige looks healthy.. minus the rabbit damage.. Everyone in our nieghborhood has glorious irises.. we are clearly doing something wrong.

Last year I transplanted the iris in front of the ''black walnut bed'' from the front to the back. I had blooms on all those large enough to produce a bloom. Laurief is the person to ask. She knows more than anyone I know.

I don't have problems growing iris under black walnuts. If the tree is limbed high enough so that the iris gets good light, it shouldn't be a problem. If they are getting mushy check your drainage. How deep are you planting them?

Diann

I think we may have planted them too deep.. a couple inches.. somewhere last night I was reading they should barely be covered with dirt and with the leaves facing the sun. I am not sure why that end of the bed would have worse drainage, but maybe I will dig it up and work on the soil a bit. the other 6 are fine. As for light its in the sun from 10am on.

Black walnuts produce a quinone called juglone which can be toxic to some plants, but according the the study linked below

http://web1.msue.msu.edu/imp/modzz/00001916.html

Siberian iris, at least, can manage okay near walnuts. The study also suggests that actual contact with the walnut tree roots is the problem.

katie

If they are bearded iris, and I think Superstition is, then you probably figured out your problem. Bearded iris like to have 2/3's of their rhizome out of the soil and they like dry feet. You might want to raise them up a bit. :) Good luck!

Diann