Wild four-o’ clock is actually native to the east of the Rocky Mountains, from Montana to Mexico and east to Wisconsin and Alabama. It is a Class A noxious weed listed in 1989, which means the state requires the land owner to eradicate this weed from their property. This weed has the capability of establishing itself in a wide range of habitats, which include orchards, alfalfa fields, range lands, rocky and heavy cultivated soils, fence rows, dry meadows, railroad embankments and in industrial/residential vacant lots. This plant is also found along river banks in high water areas. Washington State has evidence of it spreading over several hundred acres and threatening itsabundant agricultural and range lands
Plant Description:
This weed is a perennial herb that can be up to 3 or 4 feet tall and sometimes have a woody base with a thick, black taproot that can grow up to 2 feet downward. The overall shape is bushy with opposite branches and leaves. The stems are smooth and often four-sided. This weed is hard to notice during the most of the day as the flowers only open late in the afternoon and whither early the next morning, which is where its name came from. Flowers grow in clusters of 3 to 5 with a diameter of 3/8 inches from a short, hairy flowerstalk at the tips of the plant.The flowers range from a reddish to lavender color.It blooms throughout the summer. The seedsare hard, elongated nutlets thatare ready for dispersal from July to September. This plant can also spread by roots and when stems are broken from the crown of the plant, new stems will sprout.
Control Methods:
Due to the roots being strongly rooted and the stems breaking easily at the crown, hand pulling is not recommended. Small infestations can be dug up with all roots removed. Repeated mowing will prevent seed production and lower seed bank and eventually the plant will die from nutrient loss in the root system.For cultural methods of control, plowing infested areas and planting a cultivated crop for 2 years will work. Field corn has shown to compete well with wild four o’ clock.The extensive root system and waxy covering on the leaves, makes the effectiveness of the herbicides challenging. For herbicide recommendations please refer to the PNW Weed Management Handbook or contact the Chelan County Noxious Weed board for assistance.
Posted: 04/30/2019 02:33 PM
Last Updated: 04/30/2019 02:36 PM
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The information contained on this site is provided as a courtesy of the Chelan County. Where it exists, the "Index.txt" will contain a brief explanation of files contained in this folder
Chelan County makes every effort to ensure the accuracy of the information provided on its web site. However, due to the possibility of transmission errors, HTML browser capabilities, changes made since the last update to the site, etc., neither Chelan County, nor any agency, officer or employee of Chelan County warrants the accuracy, reliability, or timeliness of any information published by this system and shall not be held liable for any losses caused by reliance on the accuracy, reliability, or timeliness of such information. Portions of such information may be incorrect or not current. Any person or entity that relies on any information obtained from this system does so at his or her own risk.
PLEASE NOTE: FTP browsing is no longer supported on the latest browsers, please refer below to acccess our FTP content.
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By clicking continue, you confirm that you have read, understood and agreed to this disclaimer.
The information contained on this site is provided as a courtesy of the Chelan County. Where it exists, the "Index.txt" will contain a brief explanation of files contained in this folder
Chelan County makes every effort to ensure the accuracy of the information provided on its web site. However, due to the possibility of transmission errors, HTML browser capabilities, changes made since the last update to the site, etc., neither Chelan County, nor any agency, officer or employee of Chelan County warrants the accuracy, reliability, or timeliness of any information published by this system and shall not be held liable for any losses caused by reliance on the accuracy, reliability, or timeliness of such information. Portions of such information may be incorrect or not current. Any person or entity that relies on any information obtained from this system does so at his or her own risk.
By clicking continue, you confirm that you have read, understood and agreed to this disclaimer.
The information contained on this site is provided as a courtesy of the Chelan County. Where it exists, the "Index.txt" will contain a brief explanation of files contained in this folder
Chelan County makes every effort to ensure the accuracy of the information provided on its web site. However, due to the possibility of transmission errors, HTML browser capabilities, changes made since the last update to the site, etc., neither Chelan County, nor any agency, officer or employee of Chelan County warrants the accuracy, reliability, or timeliness of any information published by this system and shall not be held liable for any losses caused by reliance on the accuracy, reliability, or timeliness of such information. Portions of such information may be incorrect or not current. Any person or entity that relies on any information obtained from this system does so at his or her own risk.
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