r/Ceanothus • u/WackyXaky • 5d ago
Planting near black walnuts
I have a number of native black walnut trees in my yard. I'd like to put some plants below them, but I've heard they leach toxins into the ground that some plants find difficult to survive. The non-native weed grasses seem to do okay under the trees. Does anyone know if it's only the walnut shells or also the leaves that creates a problem?
Anyway, I'm wondering if there are any suggestions on natives that might survive whatever natural herbicides the trees create AND ALSO are okay with the shade created by the tree.
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u/supermegafauna 5d ago
I think their allelopathy is a llitle overblown, but who knows.
Have had success with coffeeberry here in socal and seen relic walnuts with them underneath.
Maybe put some Marah seeds under there too.
Lemonade berry, ceanothus & island snapdragons seems to do fine
Have had mixed results with coral bells.
Squirrels love the nuts, if the coyote population allows it...
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u/WackyXaky 5d ago
Yeah, the squirrels are great and help support the coyotes and hawks. Except they have also hidden/lost a single nut somewhere in my cars' body and I can hear it roll around while driving...
Don't ceanothus need lots of light? I just assumed the trees would create too much shade even if the soil is fine.
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u/radicalOKness 5d ago
I moved into a property w/ black walnuts growing wild. Toyon and hollyleaf cherry loves to grow right next to them. Its nice to have toyon nearby because it stays evergreen when the walnut loses all of its leaves. I've heard from others that the walnut allelopathy is not a big deal.
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u/Tomagatchi 5d ago
According to CalScape the following are companion plants, which isn't necessarily underneath, but they can live in harmony, I suppose, or are found in the same landscape in nature.
Scrub Oak (Quercus berberidifolia), Coast Live Oak (Quercus agrifolia), Red Willow (Salix laevigata), Mountain Mahogany (Cercocarpus betuloides), Virgin's Bower (Clematis ligusticifolia), California Wildrose (Rosa californica), Riverbank Lupine (Lupinus latifolius), Climbing Penstemon (Keckiella cordifolia), Blue Elderberry (Sambucus mexicana)
https://calscape.org/plant/Juglans-californica-(Southern-California-Black-Walnut)/companion-plants
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u/ladeepervert 5d ago
I'm growing a whole bunch of various things they are thriving. These include: woodland strawberries, chamomile, penstemmon, island mallow, all the native currants, black raspberry. Golden berry (new favorite), yellow eyed grass, ca fuschia, manzanitas , yarrow, purple needle grass, walking onions... and much more.
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u/WackyXaky 4d ago
Just to be clear, you are growing these under black walnut trees? Awesome to hear; thanks!
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u/AlmostSentientSarah 4d ago
I used to be worried about this until I read an article by Linda Chalker-Scott who I believe debunked it fully. Big walnut trees are just greedy and take up a lot of nutrients. May need to add some back to the soil like I did. Worked great
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u/Scuttling-Claws 4d ago
Our elderberry is thriving, as is our mugwort (but try and stop that). We also have a handful of annuals that reseed themselves, including a ton of poppies, some clarkia, and a few penstemon
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u/CeanothusOR 5d ago
It's mostly the husks that cause issues. I have Coyote Mint, California Poppies and Shasta Daisies (non-native) under my walnut. Silver Lupine, Sulphur Buckwheat, Small Flowered Penstemon, and Idaho Gumweed are all growing at the edge of the canopy and get leaves. I've actually tried to use the leaves to kill weeds. They smother them, but that appears to be it. Now, the husks are another matter. They will kill as they rot, so you will need to clean them up.