Tootswisc, There are many plants you can grow beneath a Black Walnut. Do a search for "Black Walnut Tolerant Plants" or "Juglone Toxin" or any variation of this. There are a number of university reports and personal reports. There is even a nursery that has a short list. Be aware the lists vary, but if you find the same plant on two lists, it is likely tolerant. These are plants that have been observed growing beneath or near BW trees.

The reason I am experimenting with roses is:
1. The multiflora species is on the list. No one in their right mind would plant this rose as it is an absolute bramble. However, there are many hybrids that are in commerce that have multiflora genes and are quite lovely and much "tamer"-- Hybrid musk roses, polyantha roses, and multiflora hybrid climbers.

2. The most important reason is that others on the Garden Web rose forum have reported they have these roses growing up a BW tree or within the drip line.

As to what you should plant I can tell you what else I have beneath the tree and let you decide.

shasta daisies, daylilies, phylox (paniculata), impatines, berginia, lobilia, campanula carpacta, hosta, astilbe, certain ferns (toothed wood fern, cinnamon fern, christmas fern)lambs ear, monada, tiarella, aruncus, hollyhock, ajuga and lamiam. These are planted according to the amount of sunlight in that particular spot. Some require more shade than others.

This fall, if I get to it, or next spring, I plan to put purple leaf sand cherry and japanese maple. Also, I am going to try a hydrangea macrophilia.

One good thing about the BW is they are among the last trees to leaf out in the spring and the first to loose their leaves in the fall (indead they drop leaves year around). This is good for light exposure. They generally do not have real dense shade most of the year. For once blooming roses like the multiflora hybrids, this is somewhat friendly as it gives the roses more sun. Roses generally need 6 hours of sun daily, year around. Hybrid musk roses will grow and bloom with somewhat less sunlight, say 4 to 5 hours daily. Some of the polyanthas are also shade tolerant, like Cecile Brunner. Also, quite by accident I discovered rugosa roses are tolerant, or so far anyway, of the Juglone Toxin.

All I can say is try. That's what I have done. And good luck! It seems to help to have copious amounts of organic matter in the garden. This seems to break down the toxin much quicker and somewhat dilutes the affect.

I can't believe you listed so many things that would grow under the Black Walnut tree. I tried Morning Glories on the fence and they did not bloom..None if the annuals grew..Is there something I need to add to the soil?

The only annual I have been able to grow is Impatiens. They thrive.
Organic matter in copious amounts seems to dilute the toxin. This will help with anything that is "tolerant". I fertilizes my Impatiens last year with compost tea and they grew big and bloomed until frost.
I transplanted a Japanese maple last fall and as of yesterday it is doing just fine. I haven't lost any of the plants yet, but the spring will tell the true tale.
Good luck.

There are many many plants that you can grow successfully in the vicinity of black walnuts. I have quite a few BW's in my yard and have come to believe that you don't know for sure what will grow until you try it. Many things that were listed as susceptible to juglone toxicity have done quite well...some directly under a walnut. Please understand that I am not saying that black walnut toxicity is not a problem...I am sure it is, but sometimes I think the walnut gets blamed when other problems, such as dry shade, and root competition for moisture and nutrients in wooded areas can be the real culprit. If you are interested in a rather comprehensive listing of juglone tolerant plants, I believe the University of Ohio Extension Service has the best one I've seen.

Now is such a great time to try different things-since spreading perenials are almost weed like. Why not put your extras under walnuts. This year returning so far I have sweet woodruff, bee balm, ajuga, a plain green hosta (more interesting hosta's have not appeared yet), peonies, columbine, lots and lots of wild phlox, common hydrangia, virginia blue bells(hooray I say). I plan to transplant holly hocks, iris's, a different hosta or two, spiderwort, an old fashion type wild rose bush, day lily's, ferns pacasandra. My little woods area has about 10 giant trees-walnuts and black cherry. Theres alot of junk out there but slowly I am cleaning it up. I hope the 2 kinds of sumac I put out there last year will come back. There is no way that I could rake the leaves and walnuts up. The squirrels get most of the nuts and the wind takes alot of the leaves. I'm just going to keep trying to grow stuff out there and hope for the best. I love hearing about what other people are growing in their walnut spaces. Diane

Hawkeye-Belle -

How're those roses doing, or is it still too early to tell?

I still haven't decided which rose to put in near my BW... I was almost 100% decided on rugosa blanc double de coubert, but then changed my mind after reading so many people complain about the appearance of the flowers as they fade (and I'm not good enough about deadheading to deal). I"m sort of thinking clotilde soupert (polyantha) at the moment, but still am not 100% sure...

Lisaloo,
My roses are budded, except for Penelope and Daybreak that was prunned to the ground. Penelope is bounding back about 10 inches now. Daybreak is about 1/2 inch. He just started. I am suspicious of his tolerance. Never has looked very good.
The best of the HMs are probably ballerina, erfurt and prosperity. They look best of the hybrid musks.
Of the climbers, moved Lavendar lassie-don't think it was getting enough sun, same with Veilchenblau. They both still qualify for the experiment because they are still within the root zone of the BWs. However both Russeliana and Paul's Himalayan Musk are growing gang busters and both have buds. This will be the first year for PHM to bloom. I hear he is a slow starter.
I haven't tried Polyanthas around them, but others have Cecile Brunner growing near BWs. With their multiflora parents, they should be OK. I intend to plant one or two around the big BW in my front yard. Haven't gotten there, yet.
Of the polyanthas, you might want to consider Marie Pavie. I just purchased her this spring-she's planted in my "safe zone", but what a fragrance and a beautiful flower. Got her at Antique Rose Emporium.

I have suckers of Charles Albanel and Martin Forbisher planted last fall in the area with the HMs. So far they are doing well. I think most any rugosa will work. I would start with the obvious rugose plants - stay away from Conrad F. Meyer and Rugelda (not obvious looking rugosas).

Let me know what you decide. And, good luck!