Planting under a Black Walnut Tree

I have a horse shoe shaped driveway. I want to plant the whole center area with perenials and shrubs. But there's already a mature black walnut tree there. I put a rhododendren in three years ago. It seemed okay the first couple years but this year it didn't bloom and now it's dead. I put a bare rootclimbing rose in this spring. It wouldn't grow. I replaced it with a potted climbing rose. I put the bare root into a bucket of water, it sprouted, and is now very happy in another location. I just relocated the potted rose because it's been going down hill. Does anyone know what plants will prosper under a black walnut. I would cut the tree down but my mother-in-law knows too many good recipes to use the nuts in. Help please.

Some plants such as tomato, potato, blackberry apple, crabapple, most azaleas and rhododendron will not grow well or actually be killed when planted within the root zone of Black Walnut trees.

The roots of the Black Walnut, Butternut and any Persian Walnut that has been grafted onto black walnut root stock produce a substance known as juglone. It is toxic to some plants and the toxic zone can average 50 to 60 feet radius from the trunk of the tree but could be as far as 80 feet. The toxic zone will increase each year as the tree grows. Juglone toxin occurs in the leaves, bark, and wood of the black walnut but contain a lower concentration than in the roots. Juglone is poorly soluble in water and does not move very far in the soil.

Walnut and Butternut leaves can be composted because the toxin breaks down when exposed to air, water and bacteria. Sawdust mulch, fresh sawdust or chips from tree pruning should not be used for plants sensitive to juglone.

Horses may be affected by black walnut chips or sawdust if used as bedding material. Close association with these trees while pollen is being shed (usually in May) may produce allergic symptoms in both horses and humans.

Not all plants are sensitive to juglone. Some plants that have been known to grow under or near the trees are Japanese Maple, Eastern Redbud, Rose of Sharon, Black Raspberry, Calendula, Pansy, Peach, Cherry, Plum, Hollyhocks, European Wild Ginger, Sweet Woodruff, and Spiderwort. Vegetables such as squashes, melons, beans, carrots, and corn can be grown.

Wow! Thanks Raven. I do have a lot of eastern redbud.

You are welcome!!
Rose of Sharon Trees come in many different colors and with a nice Red japanese Maple as a companion plant and perhaps Hollyhocks under with Astibe it will give you a nice entrance focal point.

Hostas do very well under Black Walnut too. Ferns are suppose to but mine didn't. It could have had something to do with the poultry and their scratching tho. I also use that area to set out large pots. Put down a large piece of landscape fabric or black plastic and maybe a layer of rocks you think are pretty. Put the pots between the rocks.

My hosta has not done well under the Poison Tree, as I have renamed it. A wild blackberry is surviving, but not much else. I've killed a large variety of plants under our two, even some that were recommended as survivors. Some ground covers will do all right, and I have one large unidentified plant that has grown well and gets about 18" across. I'm planning on dividing it next spring....

Kill list. Daisies, snapdragons, hosta, barberry, sedum, potatoes that I started from eyes when they got old, alyssum, lilies, petunias, four oclocks, cosmos, virginia creeper, and more. sigh. And the nuts aren't any good because the trees are ancient. If you cut them down, the juglone stays in the soil for years. I'm still trying

Meezer, you have probably done this already, but if you google just the word Juglone, you get some really good sites for plants supposedly tolerant to it.

I have a huge list from a garden site, and am trying (and executing) everything on the list. Jap. maples are not hardy here unless protected, and I've lost hollyhocks under there too. I'm thinking of trying a lasagna garden, with shallow rooted plants that might not grow down into the contaminated soil. If that doesn't work, it will be giant pots of petunias not set into the ground at all.

I have a huge black walnut tree too. Daylilies can do well - but start with inexpensive ones. As far as ground cover, runner violets work pretty well. I have a little trouble with Hosta but it's really too warm here. I have a Blue Wave hydrangea that doesn't seem to have a problem. And I do have pots. The plants that really do well under mine are Ligularia. They wouldn't survive your winters though. I'm having a little trouble here because my zone is so far away. I am working on planning redoing the area next spring though, so I'll be interested in what you find out.

Here are some links with lists of plants.
http://ohioline.osu.edu/hyg-fact/1000/1148.html
http://www.ext.vt.edu/pubs/nursery/430-021/430-021.html

I have three walnut trees and my neighbor has two. I have daffodils,
iris, astilbes, delphiniums, husker red penstemons, white bleeding
hearts, blue flax, delphinium, red shirley poppy, coral bells, cardinal
flower, balloon flower,cimicifugia, corydalis, tall american bell-
flower, Franz Shubert phlox, and iris under mine.

Very nice! You must have good soil or you've amended it well. What do you think your secret is?

I find that all daylillies, all euonymous, all hosta, cimicifuga, lily of the valley, canadian hemlock, quince, impatiens, iris, sedum spectabile and lungwort grow well under black walnuts.

In 1992, I created an 80' x8' bed for peonies. My yard was uneven, so I ordered a truckload of dirt. I never had a weed in it. I mixed in my compost for each flower that I planted. The peonies blighted, so I moved them out. Lately, I've just used the dirt that's there. I also have plenty of weeds now!

No wonder things grow - I just pulled a peony out because it blighted too - replaced it with a special daylily that will give me more color. That is a lot of peonies to lose though.

I just planted 3 ligularia palmatiloba under the tree - I already have quite a few ligularia cristata (they don't have it on this site though) and they like it under the walnut so I thought I might try another form of it too and put with the camellias and tree ferns. The foliage is so great that I think it ought to be used more.
http://www.bigdipperfarm.com/cgi-bin/searchstuff.pl?Botanical=Ligularia

Doss: Sorry about jumping in here but/////////
Thank you Thank you!
I have several Black walnut on my property. The biggist being just to the left of my drive way I checked with a couple of local nurserys they basicly said don't bother grass is about it! I have wanted to circle the trunk with one layer of 6x8 retainer block, to make it easyer to mow around and then plant hostas or something like that in the ring. also that will not raise the baseline of the trunk any as it is already slightly raised next to the trunk, which is what one nursery cautioned me against raising the level around the trunk. I copied the list of the ones that should do well, Thanks again (:>)
Russ

I'm going to try some pampas grass in the bed next to one of them this year, as grasses seem to do all right. Many of the plants on the lists from universities are not hardy in zone 5. If I can get two or three pampas started as a "back row" I could put daylilies and phlox in front...for color...

meezersfive;
Pampas grass, sounds fine, I think I would sink some kind of barrier down to keep the roots from traveling too far from where you want the PG. I planted some beside my waterfall it has taken over I have to keep diging up the roots but if I miss one piece that is a new plant to control.
I will be puting a 6" strip of vinal sideing around the tree under a ring of cement. Cement being the foundation for the blocks to make a slightly raised bed for the shade garden, also will have a weed barrier under the soil used to build up within the ring.
Should help to control things from traveling either direction. looks like a plan to me.Think I will start on that before the grass gets started again. will post pic when started.
Barb & Russ

Sounds liike a good approach. I was planning on sinking some old plastic trash cans with the bottoms cut out to prevent them from traveling too far! I've had artemesia that has done that but their roots are shallow enough you can just yank out the runaways. I may investigate some other grasses similar to Pampas that don't spread like that, and if I can find some that are hardy here, I will do those instead. Our garden centers arent known for carrying unusual items, they are awash in petunias and such, so I may end up mail ordering. I should probably just dig up my wild blackberries and stick them in there, they seem to do just fine down near the other tree. Except I wanted "pretty".

I have some ferns I plan to transplant there. I have been trying to get some jack in the pulpit started had some growing finaly north side of house. Would like to get some started under the walnut as well and some hostas with varigated leaves. and had thought of trying some colieus as well That gives several different paterns and a blend of color. I haven't seen any thing on Elephant Ears but that would also be a little different.
I see that it says Tulips, rudbeckia,sedum,yarrow,- - - honeysuckle,hydrangea clematis shasta daisy as well as geraniums that is according to the hyper link that
Doss; gave in an earlier forum on this page all could be made to look special. depending on a trellis for the vines I was toying with that thought but not sure of that , given the location. am I rambling, I'm sorry. I tend to at times.
I just don't like makeing that tight of a turn with the rider mower. And I'm not about to do a lot of push mowing. for an acre of yard. yeah I'm a little lazy.

I had no luck with Shasta Daisies, they were stunted and didn't come back the second year. Hosta does moderately well, sedum nearly croaked before I rescued it. I have some rudbeckia that I'm going to try down in the far corner by the other tree and see how it does.

Just a thought for the death tree. Plant a vineing plant beyond the drip line and direct its growth to the tree. Then use hardscape things, old farm machinery, benches, whatever to add character to your garden.
IE Virgina Creeper, hops, Porcealin vine etc. Check about invasivness in your area.

LOL, the virginia creeper was one of the first things it killed!

Planted outside the drip line?

An acre of yard in grass is quite a push with a hand mower, certainly. I do have hydrangeas that grow under the walnut. 'Blue Wave' I believe. I'm sure that you know this but the generic honeysuckle can be invasive - although maybe that's what we want. I've tried a clematis but that didn't work. Perhaps a climbing hydrangea?

Here's a photo of what's under my walnut tree.

Well outside the drip line. Bear in mind these are very old trees, and the area that was cleared for this subdivision was just used for crops, no clean up of the leaves or debris in autumn, so I believe the soil is thoroughly saturated with juglone. Did get a nice buy on day lilies at HD this morning.....

I just built two beds for veggies - outside the dripline - my starts are doing well - we will see how the plants do

I have kurume azaleas growing quite happily under my walnut even though it says that they will kill azaleas. Only hardy down to Zone 7. I really like the kurumes. Also butterfly bushes do well.

Found some "secret dirt" not under a Black Walnut but under a power line any ideas?

Not quite clear on what you mean by 'secret dirt' under a power line. Could you clarify. Maybe I'm just a little dense?

'secret dirt' dirt i don't own but can plant in

Plant non-invasive wild flowers. Any thing else trees etc will be cut by the crew who clears the area.

Gonna do "short term" veggies and hope I can harvest before they get to them

Red and yellow cherry tomatoes are good - I invite all of my neighbors to have some as they pass by. Maybe the ground crews could have some and leave the rest for you!

We had a black walnut tree in Ohio and nothing and I mean nothing would grow under it.
we even tried a little garden about 20 yards away and it would not grow.
Good luck
Linda

I have 7 black walnuts around my yard. The squirrels love me. A Golden Raintree grows well under one if if you want an understory tree there. Mostly I just have grass under my trees, though. It seems safer, although some columbine has come up wild under one and done well there for a few years now. Cannas I threw away also come up year after year close to another one, too.

Dyson, I planted in secret dirt under a powerline and when they came to drill holes in the pole and squirt it with something poisonous, they jumped my neighbor about it. Said you aren't supposed to plant there. Well, then they need to come pull the weeds and walnut trees surrounding the pole, don't you think? (The flowers eventually died out.)

I like to plant in secret dirt, sometimes things are so ugly that you have to give nature a helping hand. One time we saw sunflowers all along a highway, about fifty feet apart, somebody must have thrown them out the window of their car. It was rather delightful!!

Cool! I love to spread seeds around. I threw a lot of old seed, but nothing made it. This year, as soon as the prolific ones start to drop I'll be Sally Seed.

One important thing to do is to be sure that you clean up leaves etc from under the walnut when they fall. That really seems to help.

We rake into piles and lay a tarp out. You can get a lot of leaves on it, and it's easy to drag and dump. I cover the garden and burn them when the wind blows the smoke out to the country and not over the town.