Alleopathis =Weed suppresive plants.
The most basic definition of an allelopathic plant is one plant affecting the growth of another in either a positive or negative way. Plant allelopathy is a natural means of survival in nature, reducing competition from other plants for water, nutrients, and the sun. This occurs through the release of allelochemicals, which can be found throughout different parts of the plant; stems, leaves, flowers, roots, bark, and seeds. Allelochemicals are most commonly stored in leaves, making Fall the most effective time for the chemicals to be released. Leaves are dropped and decomposed and affect the growth of surrounding plants for the following spring growing season. The chemicals can inhibit other plant’s seed sprouting, root development, or nutrient intake.
The Black Walnut tree is a prime example of an allelopathic plant, the toxic chemical in Black Walnut is Juglone found throughout the plant but concentrated in the roots. When Nightshade plants such as; Azaleas, Mountain laurels, Rhododendron, and Privets are planted in the surrounding root system of a Black Walnut, they soon show signs of stress and proceed to wilt and die. Although, there are also many plants that can withstand the chemical released by the Black Walnut and others still that may benefit from the chemical.
Mulching and improving the soil with organic matter can in some cases be used to prevent the allelopathic properties.
Although the effect is harmful to some plants it can be used to benefit the gardener, considered Mother Nature’s own “weed killer”. For the gardener it can be used as a natural herbicide, many turf grasses and cover crops have allelopathic properties that can improve weed suppression.
Other organisms, such as bacteria, viruses, and fungi, can also be allelopathic, an example is the way the fungus penicillin can kill bacteria.
