[secondnature]

Good Morning! I am in the Portland Oregon area.

I have been educating myself on allelopathic-tolerant plant material to plant beneath my client's prized Walnut. It is a huge old tree, really just beautiful in form. An arborist came out and thinned the canopy a bit so more sunlight can come in.

Her existing ground is barren, due to this tree. At this point, I am not convinced it is an English but I am thinking it might be a Black.

What have others done to effectively use the area under these trees?

Does creating raised bermed beds with fresh soil reduce the issues of the juglans getting to the plant material?

Messy they are, and she will need to be able to remove the debris on a regular basis. Has anyone graveled beneath? Is there a ground cover that works well that is tolerant of the juglans?

Thanks for responding.....any experience I would appreciate. Her rectangular back yard is deep and more narrow.....so much land to utilize.

[Terre]

Read somewhere that Univ of Colorado did some research on this issue, that shows not everything is susceptible to juglone if excellent drainage can be provided. So raised berms might be an option if you can ensure great drainage.

Years ago, I had an acreage in Tulsa that was loaded with black walnuts. I cursed them becuause I had to rake the yard before I could mow. Every nut would stop my riding mower dead in its' tracks. However, I did have good luck growing hostas and heucheras under them. Good shade and moisture, and the hostas in particular didn't seem to have any issue with it.

I did find this:

Trees for Problem Landscape Sites -- The Walnut Tree: Allelopathic Effects and Tolerant Plants

[NCSULandscaper]

Got this list from Virginia Tech.


Tolerant trees and shrubs

* arborvitae, American
* ash, white
* barberry
* beech, American
* birch, black; 'Heritage' river
* boxelder
* buckeye, Ohio
* catalpa
* cherry, black
* crabapple
* daphne
* dogwood, flowering
* elderberry
* elm, American
* forsythia
* fringetree
* goldenraintree
* globeflower
* gum, black
* hawthorn
* hemlock, Canadian
* hibiscus
* hickory
* holly, American
* honeylocust
* honeysuckle, amur; tatarian
* hydrangea
* lilac
* locust, black
* maple, red; sugar; black; Japanese
* ninebark
* oak, white; red; scarlet
* pawpaw
* pear, callery
* pine, Virginia
* privet
* red cedar, eastern
* redbud, eastern
* sassafrass
* serviceberry
* silverbell, Carolina
* spruce, Norway
* sumac
* sweetgum
* sycamore
* tulip tree
* viburnums (some species)
* witchhazel

Tolerant vines, ground covers and flowers

* anemone
* aster
* astilbe
* bee balm
* begonia
* bittersweet
* calendula
* clematis (virginsbower)
* coral bells
* creeper, Virginia
* daffodil
* daisy, shasta
* daylily
* evening primrose
* fern
* geraniums, hardy
* goldenrod
* grape, wild
* hollyhock
* hosta
* hyacinth, grape; oriental
* iris, siberian
* ironweed
* jack-in-the-pulpit
* lamb's ear
* liriope
* lobelia
* may apple
* morning glory
* mullein
* phlox
* primrose
* raspberry, black
* rose, wild
* rudbeckia
* scilla
* sedum
* speedwell
* spiderwort
* St. John's wort
* sunflower
* trillium
* tulip
* violet
* wisteria
* yarrow

Plants damaged by juglone

* apple
* azalea
* birch, white
* blackberry
* blueberry
* chrysanthemum
* crocus, autumn
* forget-me-not
* grape, domestic
* lily-of-the-valley
* linden
* mountain laurel
* peony
* pine
* potato
* rhododendron
* thyme
* tomato

[secondnature]

Hi Terre,

I have found some lists online of tolerant plant material that I will pull from (limited, but there are quite a few varieties that will put up with it). It has been interesting to read about this type of thing...!

The tree is such a prominent part of my client's yard, and because of it, the design is almost completely centered around it. With so much debris coming from the tree at different times, I feel like we need to keep it 'clean' having a large graveled area around the tree itself that she can entertain in but is easy to rake. Nearest the house (furthest area from the tree) I have proposed a paver area with bermed beds surrounding....so maybe there is hope!

Thanks for your help!

Originally Posted by Terre

Read somewhere that Univ of Colorado did some research on this issue, that shows not everything is susceptible to juglone if excellent drainage can be provided. So raised berms might be an option if you can ensure great drainage.

Years ago, I had an acreage in Tulsa that was loaded with black walnuts. I cursed them becuause I had to rake the yard before I could mow. Every nut would stop my riding mower dead in its' tracks. However, I did have good luck growing hostas and heucheras under them. Good shade and moisture, and the hostas in particular didn't seem to have any issue with it.

I did find this:

Trees for Problem Landscape Sites -- The Walnut Tree: Allelopathic Effects and Tolerant Plants

[secondnature]

Thank you for the list! I did see this one online. There is really quite a few that will work in our situation.

Originally Posted by NCSULandscaper

Got this list from Virginia Tech.


Tolerant trees and shrubs

* arborvitae, American
* ash, white
* barberry
* beech, American
* birch, black; 'Heritage' river
* boxelder
* buckeye, Ohio
* catalpa
* cherry, black
* crabapple
* daphne
* dogwood, flowering
* elderberry
* elm, American
* forsythia
* fringetree
* goldenraintree
* globeflower
* gum, black
* hawthorn
* hemlock, Canadian
* hibiscus
* hickory
* holly, American
* honeylocust
* honeysuckle, amur; tatarian
* hydrangea
* lilac
* locust, black
* maple, red; sugar; black; Japanese
* ninebark
* oak, white; red; scarlet
* pawpaw
* pear, callery
* pine, Virginia
* privet
* red cedar, eastern
* redbud, eastern
* sassafrass
* serviceberry
* silverbell, Carolina
* spruce, Norway
* sumac
* sweetgum
* sycamore
* tulip tree
* viburnums (some species)
* witchhazel

Tolerant vines, ground covers and flowers

* anemone
* aster
* astilbe
* bee balm
* begonia
* bittersweet
* calendula
* clematis (virginsbower)
* coral bells
* creeper, Virginia
* daffodil
* daisy, shasta
* daylily
* evening primrose
* fern
* geraniums, hardy
* goldenrod
* grape, wild
* hollyhock
* hosta
* hyacinth, grape; oriental
* iris, siberian
* ironweed
* jack-in-the-pulpit
* lamb's ear
* liriope
* lobelia
* may apple
* morning glory
* mullein
* phlox
* primrose
* raspberry, black
* rose, wild
* rudbeckia
* scilla
* sedum
* speedwell
* spiderwort
* St. John's wort
* sunflower
* trillium
* tulip
* violet
* wisteria
* yarrow

Plants damaged by juglone

* apple
* azalea
* birch, white
* blackberry
* blueberry
* chrysanthemum
* crocus, autumn
* forget-me-not
* grape, domestic
* lily-of-the-valley
* linden
* mountain laurel
* peony
* pine
* potato
* rhododendron
* thyme
* tomato