Hi All, I am planting Black Walnut, which is the rootstock for many commercial English Walnut trees. The plan is to bud graft to English Walnut later. In the USA there is information regarding plants which are injured by the juglone the Black Walnut roots secrete, for example, blackberry seems not to grow in proximity to Black Walnut, nor to apple trees. I have not found any Australian research into the juglone issue. I am specifically interested in interplanting my Walnut food forrest with Blackwood wattle for the nitrogen fixing purpose, but also other local species for insect and bird attracting purposes. Has anyone found any Australian research on the juglone/Australian plant compatability/incompatability issues? Has anyone heard of Black Walnut use for blackberry control? Regards Mirrabooka
Walnuts are not a big commercial crop in Oz (we import them from California), so probably not a lot of agricultural research being done I suspect a lot of trees/plants have protective measures to reduce competition. I am sure cassurinas do. Elderberries excrete something that helps the break down of organic matter/carbon; so some suggest growing them near compost heaps Also read (somewhere) how emerging/germinating thyme plants release a chemical that inhibits germination of other nearby thyme seeds Perhaps we need a "companion planting" guide for trees? i suspect roots also excrete substances that drive soil micobiota in beneficial ways for the tree Apparently roots talk too
Far as I know, nothing grows under adult walnuts tress. While young it is possible to plant mixed with apricots and peaches, which start bearing fruit earlier. It is just to better use time and space until walnuts mature and close canopy. I cant think of better tree for planting along roads and places where you don't want any vegetation.
See https://www.sciencedaily.com/releases/2012/08/120803082917.htm and https://www.sciencedaily.com/releases/2012/08/120801132440.htm on this Also saw this at same site Walnut Trees May Not Be Able to Withstand Climate Change
Afew things grew under our Walnut trees(before we had to cut them down). I wasnt really into food gardenng back then and just let grow what would. Bears breeches grew magnificently and helped keep the wandering jewel weed out of this area. There were two apple trees that grew on or just past the drip line and had lovely pest free apples. Mint especially the eau de cologne mint... cant remember what else except that grasses and bluebells in particular did really well.
im in the planning stage of 1acre of walnut/hazel plantings and have been researching the same question you ask for 6+ months. Ive found repeated accounts of people successfully growing acacia amongst black walnut as well as eucalypt. No scientific studies unforrunately. I intend on interplanting ironbark for coppiced wood production and various acacia for nitrogen and as pioneers. If you have an AU source of black walnut seeds im very interested as so far all i have are the english variety.
...and in case you haven't seen it, this list published by Ohio State University's Ag dept is great to have: As you may well have also read, a number of sources report Mulberry species as a somewhat effective buffer of the root-excreted juglone. Again I have no scientific studies to point to on this, but will be planting a row of mulberry around my walnut grove to lessen the impact on surrounds and neighbours.
Gaia's Garden specifically describes building a walnut guild. I can't remember, but I think it uses hackberry as a buffer plant and then plants around that. Yup, that's on the list above. William
Yes, Gaia's Garden directly references this article by Tim Murphy on Walnut and Hackberry guilds - https://www.permaculture.org/nm/images/uploads/Walnut_Hackberry_Guilds_by_Tim_Murphy.pdf
Steve La Valley is The Botanical Ark at Warragul in Victoria. His phone number is there on google via 'True local'.Steve is very generous with his time and resources, with a passion for spreading his genetic material, (including the black walnut). Others see value of the black walnut root stock with a dreaded fungus whose name I can never remember. Leaf drop for mulch, goldmine timber, fire retardant, nuts, summer shade, winter sun, blackberry cure, what more could a Permaculturist ask for!
some more suggestions https://www.ehow.com/info_8449634_plants-grow-under-juglans-nigra.html https://www.mortonarb.org/index.php?option=com_content&view=article&id=887&Itemid=6 https://www.johnsonsflorists.com/blackwalnuttrees.html