Native Honeysuckle Bush:

Native Honeysuckle Bush:

Native Honeysuckle Bush

Black Walnut trees produce a chemical called hydrojuglone, which is found in the leaves, stems, fruit hulls, inner bark and roots. When exposed to the air or soil, hydrojuglone is oxidized into the chemical juglone. Juglone is toxic to a number of plants, but there are also many plants that are resistant to the toxins. The native plants in this category are compiled from a variety of reliable sources and from our own experience. Note: Soil that is compacted, slow draining, or lacks sufficient healthy microbial growth, will have less success supporting plants under Black Walnut trees.



Black walnut (Juglans nigra) is considered one of our most valuable native hardwood lumber trees and is often used in large-scale landscapes. In the smaller-scale home landscape, however, the leaves and fruits are considered by some to be a messy nuisance. Furthermore, while many plants can grow well in proximity to a black walnut, certain plant species’ growth is inhibited by this tree. The term “allelopathy” refers to the relationship between plants in which one plant produces a substance that inhibits the growth of sensitive plants nearby.Juglone-sensitive landscape plants should be located away from black walnut trees to avoid damage. Raised beds near trees will help minimize toxicity, but care should be taken to keep leaves, twigs, branches, and nuts out of the bed. Black walnut leaves, bark, and wood chips should not be used as landscape mulch or composted on garden plants. The best alternative is to choose plants from the list below. Be aware that some plants are aggressive or invasive in certain parts of the country.

Black Walnut trees are allelopathic, meaning that they produce a toxic chemical called juglone. Related tree species, like Hickory and Butternut, also produce juglone but at a lower level than Black Walnut. The toxin is present in fruit, leaves and branches and can be excreted from the root system into the soil. Juglone is potent enough to inhibit or kill many plant species surrounding the Walnut tree but many natives are tolerant or resistant. The natives assigned to this category are compiled from our own experience and from research in reputable books and websites.As rain falls over the black walnut tree and down through the layers of soil and rock to join the groundwater underneath, it carries bits of juglone with it into the soil. However, juglone is not very water soluble, so it tends to stay in the soil surrounding a black walnut tree, which is why there seems to be a poor growth zone that extends out from the tree itself. (The soil holds the most juglone within the black walnut tree’s canopy dripline because of the root system as well as decaying leaves and walnut shells that fall there.) (Source: www.gardeningchannel.com)



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