Exploring How Yarrow Plant Oil Affects Weed Growth

Jim Crocker
29th February, 2024

Exploring How Yarrow Plant Oil Affects Weed Growth

Image Source: Natural Science News, 2024

Key Findings

  • In a study from Tarbiat Modares University, certain yarrow plants significantly reduced weed growth
  • Two yarrow species, Achillea vermicolaris and A. aleppica, cut red root pigweed's dry matter by up to 90%
  • Key compounds like cis-Menth-2-en-1-ol and Bornyl acetate in yarrow were identified as growth inhibitors
In the ongoing battle against weeds, scientists from Tarbiat Modares University have turned to nature's own arsenal: the chemicals plants use to defend their territory. In particular, they have honed in on a group of plants known as Achillea spp., commonly referred to as yarrow, to see if they could naturally suppress a widespread and persistent weed, the red root pigweed (Amaranthus retroflexus L.)[1]. This approach, known as allelopathy, involves the release of certain chemicals by plants that can inhibit the growth of surrounding plant species. Allelopathy is not a new concept. It has been observed in various plants, including buckwheat, whose roots release substances that can inhibit the growth of certain parasitic weeds[2]. Similarly, essential oils and their components, such as terpenoids, have been studied for their potential as natural herbicides due to their phytotoxic activity, which can affect weed germination and growth[3]. Eucalyptus essential oil, for instance, has been found to contain α-terpineol, a component that significantly hampers the growth of Amaranthus retroflexus[4]. Furthermore, volatile emissions from the leaves of star anise have been shown to completely halt the growth of test plants like lettuce, with compounds like L-fenchone demonstrating particularly strong inhibitory activity[5]. Building on this foundation, the Tarbiat Modares University study explored the allelopathic effects of nine different Achillea species by incorporating their dry material into the soil at varying concentrations. Remarkably, two species, Achillea vermicolaris and A. aleppica, stood out for their effectiveness, reducing the dry matter of red root pigweed by up to 90% at very low concentrations. The study delved deeper by analyzing the essential oils of the Achillea plants through Gas Chromatography-Mass Spectrometry (GC/MS), identifying 152 different compounds. Among these, cis-Menth-2-en-1-ol, α-Terpinyl, propionate, and Bornyl acetate were found to be the most potent in hindering the pigweed's growth. This discovery not only sheds light on the specific chemicals responsible for the allelopathic effects but also underscores the potential of these naturally occurring substances as bioherbicides. The implications of this research are significant in the context of sustainable agriculture. With the rise of herbicide-resistant weeds and the environmental and health concerns associated with synthetic herbicides, finding effective natural alternatives is paramount. The Achillea species, with their strong inhibitory effects on a common weed, could offer a new tool for farmers. By using the plant material as mulch or cover crops, they could naturally suppress weeds, reducing the need for chemical interventions. This study from Tarbiat Modares University not only contributes to our understanding of plant interactions but also opens the door to practical applications in weed management. By harnessing the power of plant-derived chemicals, we can move towards more sustainable and environmentally friendly farming practices. The research demonstrates that the natural world holds many solutions to the challenges we face in agriculture, and by exploring these options, we can reduce our reliance on synthetic chemicals.

HerbsBiochemPlant Science


Main Study

1) Phytochemical analysis and allelopathic potential of essential oil of yarrow (Achillea spp.) ecotypes against redroot pigweed (Amaranthus retroflexus L.).

Published 29th February, 2024


Related Studies

2) Allelopathic Effect of Quercetin, a Flavonoid from Fagopyrum esculentum Roots in the Radicle Growth of Phelipanche ramosa: Quercetin Natural and Semisynthetic Analogues Were Used for a Structure-Activity Relationship Investigation.


3) Phytotoxic Effects and Mechanism of Action of Essential Oils and Terpenoids.


4) [Chemical composition analysis of Eucalyptus essential oil and allelopathic effects of α-terpineol].

Journal: Ying yong sheng tai xue bao = The journal of applied ecology, Issue: Vol 31, Issue 7, Jul 2020

5) Screening for Plant Volatile Emissions with Allelopathic Activity and the Identification of L-Fenchone and 1,8-Cineole from Star Anise (Illicium verum) Leaves.


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