P&PDL Picture of the Week for
November 28, 2005

Common Chickweed showing up in Thin Turf Areas

Glenn Hardebeck, Turfgrass Research Agronomist, Department of Agronomy, Purdue University

Common chickweed, as well as other winter annual broadleaf weeds, is relatively easy to spot in thin turf areas at this time of year.  Winter annuals germinate throughout the fall and grow vigorously the following spring to flower, set seed and die back as the summer heat sets in.  Often, winter annual broadleaf weeds are not noticed in a lawn until spring when they surge in size and flower.  By that time it is often better to let the summer heat complete the weed’s life cycle rather than treat with a broadleaf weed herbicide.  We usually recommend October as the primary broadleaf weed application timing, but there still may be an opportunity to treat seedling annual broadleaf weeds yet this year.  Good control may still be possible if mother nature gives us a few sunny days of 50 degrees F or higher in order to make a broadleaf application and allow it to be absorbed by the broadleaf weeds.  Remember that uniform application and proper rate are more important than haggling over exactly which herbicide is the best.  With that said, low volatile ester formulations are generally better during cooler weather.

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Common chickweed seedlings in a thin turf stand.

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service