Examples of Weed Seed Production Per Plant

Learn about the “weed seed bank” and how the “never let ’em seed” rule can help maintain a weed-free garden. 

By Robert Norris, Ph.D., Fellow of the Weed Science Society of America 

Most people don’t realize that a weed can produce literally thousands — or even millions — of seeds per plant. The chart shows the number of seeds coming from single weed plants. Learn more about the “weed seed bank” in Never Let ’Em Seed.

Weed Name  Weeds Per Plant  Where the Plant Was Located 
Barnyardgrass, Echinochloa crus-galli  750,000 Davis, CA
Purslane, Portulaca oleracea  > 2,000,000 Davis, CA
Black nightshade, Solanum ptycanthum  >800,000 Rosemount, MN
Puncturevine, Tribulus terrestris  >100,000 Pullman, WA
Powell amaranth, Amaranthus powellii  268,000 Freeville, NY
Shepherd’s purse, Capsella bursa-pastoris  40,000 Sheffield, UK
Chickweed, Stellaria media  25,000 Rothamsted, UK

Data collected by various researchers around the globe.