Weeds Can Reroot (March 18, 2015)

Few farmers can walk through their fields without stopping to pull an occasional weed that is growing above the crop. Uprooting weeds mechanically or by hand can be very satisfying when there are few of them. Pulling or cultivating weeds does not always mean that they will die and not produce seed. Cheryl Wilen, a farm advisor in San Diego County, has posted the following video of of an annual sowthistle plant that was uprooted but continued to flower and produce seed. ( Click here to watch Chetyl’s Video) studied the influence of uprooting time on seed production in common purslane. The objective of his study was to determine the viability of purslane seed produced from plant that were uprooted from one to six weeks after emergence. He found that no viable seed was produced from plants that were uprooted one and two weeks after emergence. Some viable seed was produced at three weeks and this increased rapidly at 4 to 6 weeks. Preirrigating during ground preparation and not disking emerged purslane for three weeks or more increases rather than decreases the problem during the growing season.

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To contact Barry Tickes go to: btickes@ag.arizona.edu.