Permaculture Information Web

[Richard Morris <webmaster AT pfaf.org>]

Hi Folks,
        I hope most people have been following the posts on the pclist
on Persimon Guilds and Black Walnut guild.

I tought it might be constructive to examin one of the posts and see how 
we colud fit it into database.

> In response to the disparaging comments about Black Walnut, I'm posting my 
> research on Black Walnut ecology and companion planting. A list of 
> productive species for Black Walnut understory appears at the bottom.
>
> Rob Scott
> Urbana Permaculture Project
> Urbana, IL
>
> Black Walnuts (Juglans nigra) and Hackberry (Celtis occidentalis) occur 
> together naturally, both are reported to be allelopathic, for separate but 
> overlapping sets of plants. In warmer climates, the closely related 
> Sugarberry (Celtis laevigata) would be a more fruitful associate.

One example of plants growing together naturally.
One example of an allelopathic relationship.

> Why is Black Walnut toxic?
>
> Black Walnuts produce a toxin called "juglone" in all parts of the tree. 
> It is an antirespiratory compound with a phenolic ring. It probably 
> evolved to deter insect pests, not plants or humans. Fishermen have used 
> ground up walnut hulls to attract fish to the surface of the water; the 
> juglone slows fish respiration and the fish come to the surface to 
> breathe. Juglone in leaf litter degrades in about 2 days, so raked up leaf 
> mulch is not toxic. Walnut tree roots constantly release juglone, and this 
> is why nearby plants often die.

Specific example on adverse effect of plant on other plants.

> What companion plants help Black Walnut grow?
>
> Control experiments in Illinois found that Autumn Olive (Elaeagnus sp.) 
> work better as a symbiont for promoting Black Walnut growth than Black 
> Locust (Robinia pseudoacacia). Both fix nitrogen, but the Autumn Olive 
> doesn't compete with the Black Walnut as much and seems to reduce deer 
> browse. The net effect of Black Locust was to set back Black Walnut by 
> shading. Degraded sites will yield different results as Black Locust 
> better restores depleted soils.
Some quite details description of a relationship.

> What naturally grows under Black Walnut?
>
> Redbud (Cercis canadensis), Pawpaw (Asimina triloba), and Spicebush 
> (Calycanthus occidentalis) grow as understory shrubs under Black Walnut 
> naturally in Central Illinois. Ground level  wildflowers are no less 
> abundant under Black Walnuts than in other natural forest communities.

More examples of relationships. Emphesis on specific roles of plants.

> Does Black Walnut create a lot of shade?
>
> Black Walnuts let through a lot of sunlight. Shade is "dappled" even after 
> leaves have fully emerged. Bud break in Black Walnut occurs in late 
> spring, allowing sun penetration to the forest floor for a few months 
> before leafing out. A rust fungus commonly causes anthracnose in Black 
> Walnut leading to early leaf-drop and dormancy in the fall, adding another 
> month of full sun penetration. Understory shrubs have been shown to reduce 
> anthracnose infection by breaking the ground-to-leaf cycle.
>
> What productive plants can grow under Black Walnut?
>
> (in no particular order)
> American Black Currant - Ribes americanum
> European Currant - Ribes nigra, Ribes rubrum, Ribes alba
> Missouri Gooseberry - Ribes missouriensis
> American Elderberry - Sambucus canadensis
> Black Raspberry - Rubus ideaus
> Siberian Pea Shrub - Caragana arboescens
> Mulberries - Morus nigra, Morus alba
> Alpine Strawberries - Fragaria vesca
> Goldenseal - Hydrastis canadensis
> Wild Ginger - Asarum canadense
> Pawpaw - Asimina triloba
> Redbud - Cercis canadensis - legume
> Bamboo - Phyllostachys spp.
> "Rose of Sharon" Hibiscus - Hibiscus Syriacus
> Lamb's Quarters - Chenopodium alba
> Catnip - Nepata cataria
> Daylily - Hemerocallis sp
> Sunchokes - Helianthus tuberosa
More example relationships.

> This is a good way to control the spread of sunchokes, and the tubers are 
> of fine size and quality even when shade grown. Dandelions, Violets and 
> Creeping Charlie have also grown naturally in Illinois Black Walnut 
> Guilds. Toby Hemenway mentions Woldberry (Lycium spp) in Gaia's Garden for 
> growing near Walnut, but it doesn't grow well in Illinois.
Overal a very good post, just the sort of info I'd love to get into the db.

Most seems to be specific plant-plant relationships.
Some anotation of the relationship is needed "grows under" etc.

Rich