Division of Plant Sciences

University of Missouri

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Maypop passionflower (<em>Passiflora incarnata</em>) is an increasing problem weed in a number of Missouri pastures. An average waterhemp produces approximately 300,000 seed/plant. Note the size of waterhemp seed compared to a single corn kernel. Currently, herbicide-resistant waterhemp fields like this are one of the most problematic weeds in the state. Eric Riley, former MU Weed Science Research Specialist, discusses the results of his research on the management of giant ragweed.

weed science

Fun Facts

Scotch thistle (Onopordum acanthium) is said to have helped win a battle. Norsemen came ashore planning to surprise sleeping Scottish forces and removed their boots for a quieter assault. A prickly patch of thistle growing between the two armies is said to have saved the day and became the Scottish national flower.


Welcome to the University of Missouri's Weed Science homepage. Here you can find information related to our extension, research, and teaching programs or visit some of our web resources like the Missouri Weed Identification or Herbicide Injury Guides. In our "Research Results" section, you can search results from our field research by year, herbicide, weed, or crop. Additionally, you can click on our publication section to see all of the publications and newsletter articles we provide as well as to view and/or listen to some of our power point presentations. We welcome your comments and/or suggestions about this site.

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