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Allelopath: Chemical Competition!


Survival of species is much higher when defense mechanisms are unique and enhanced in a plant. Most obvious defense mechanisms one can observe in plants are for eg., thorns on Rose stems, prickles on blackberry stems, poisonous milky sap in Milkweeds, etc. But defense mechanisms like allelochemicals that plants exude underground to outcompete other plants, is simply fascinating!

"Certain plants produce biochemicals that can diminish the vigor of other nearby plants. These allelopathic chemicals can hinder seed germination, growth rate, photosynthetic ability, reproduction, and ultimately survival of other species that lie under and nearby them".

Allelochemicals are chemicals specific to a plant species, some of the most commonly known allelochemicals are like those found in Black walnut (Juglone in Juglans) and in Hedera helix (Ivy). But did you know that even Magnolias, Pines, Cedars and Shrub Honeysuckle (Lonicera mackii) also have allelochemicals that help them outcompete other plants?

When paired correctly, certain plants can complement each other rather than outcompeting each other. For eg., Rhododendrons, Magnolias and Pines would make a great trio. Both Magnolias and Rhododendrons like acidic soil, and Pine needles can make soils quite acidic. Now both Pine needles and Magnolias exude certain allelochemicals and can keep annual weeds seeds from germinating. Here is some good info. for companion plants:

There is so much for us to still learn about understating allelochemicals and how they can be used for proactive weed control. Current research on allelochemicals and its right use in agronomy and landscape industry is fascinating and still very much evolving.

Follow us next week to learn more about which mulch to use where and how to best pair plants that will benefit each other instead of inhibiting growth by exuding allelochemicals.

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