Ononis alopecuroides (foxtail restharrow) is a woody annual (family Fabaceae) whose current distribution in California is limited to one location in San Luis Obispo County. This Mediterranean native prefers disturbed places, such as fields and pastures, as well as grasslands and oak woodlands.
Although the one known population is almost completely eradicated, foxtail restharrow has the potential to be a highly aggressive invader, forming dense stands that exclude native plants. It is considered weedy in northern and central Europe.
Ononis alopecuroides is occasionally weedy in northern and central Europe. The occurrence of O. alopecuroides in southern San Luis Obispo County, California is the first record for North America. O. alopecuroides grows best in moist areas receiving full sun. Sunny, dry areas tend to have smaller plants (0.3 m compared to 1.5 m tall and 1.5 m wide). Plants are not found in shady areas, even if the soil is moist.
The impacts of this new invader are unknown. However, O. alopecuroides has the following characteristics.
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It is considered weedy in northern Europe (where it is not native).
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It invades disturbed or dry/rocky areas.
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It forms dense stands that are capable of excluding other vegetation.
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Plants appear to be unpalatable to the horses and burros that graze within the San Luis Obispo site.
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The rapid production of many seeds suggests that established O. alopecuroides populations will be difficult to eradicate.
This plant might be poisonous
How to get rid of:
Little is known on the control of this new invader.
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It is an annual, so the focus must be on reducing or stopping seed production.
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The rootstock is weak and easily pulled from the ground.
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A 2% solution of glyphosate (e.g. Roundup®) was effective on seedlings. Apply herbicide before flowering. Glyphosate is a nonselective herbicide, so it should be used with care to prevent damaging non-target plants.
