The Black Walnuts (3) are in my neighbors yard, on the other side of the fence. The trees are older, tall & limbed-up high. The V.lentago hopefully will be a screen for privacy & to pollinate V.nudum. If the problem is juglone I want to move these far from the BW before they're too far gone, but I'd rather wait til fall. Any ideas?

Some things that grow under black walnut are: Tolerant grasses Tall fescue and Kentucky bluegrass grow well near black walnut except during drought conditions when soil moisture is low. When moisture is adequate these grasses may grow better under walnut trees than in other parts of the lawn, possibly because the soil may be more basic. Soil under black walnuts tends to be alkaline, with the pH often 0 .7 points higher than beyond the roots, thus influencing the growth of many different plants. 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

If the tree is near enough to the sensitive plant for its leaves to fall on it, the growth can be stunted. For example I have three double file viburnum all planted at the same time 10 years ago. The one near a black walnut (although it is at least 10 feet outside its drip line) is sbout half the size of the other two. Good luck!

Studies also showed an interesting correlation between good drainage and lesser concentrations of juglone in the soil. There are even microorganisms that nullify or breakdown juglone and soil components that interfere with the toxicity. Every situation is different, so there's no concrete answer to be had. There will always be someone with the 'special' tree, shrub, location, etc, where something does well and it shouldn't; usually there's an attribute that will explain it. The walnut that has such a great stand of vegetation beneath it that I've observed has a heck of a terrific situation for drainage. Heavy organic matter added to the soil probably helps there as well.