Johnsongrass in Grape Plantings
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Johnsongrass (Sorghum halepense) is an aggressive perennial common in agronomic fields, along roadways, and in waterways and areas that are prone to flooding. Mature leaf blades are 5 to 20 inches long with obvious white ribs down their centers. Plants reproduce by seed and by perennial rhizomes, making control difficult. Rhizomes are stout compared to other grasses and can begin forming as quickly as 1 month after seed germination.
Johnsongrass growth habit.
(Photo: Chris Evans, University of Illinois, Bugwood.org)
Johnsongrass in bloom.
(Photo: Ohio State Weed Laboratory, The Ohio State University, Bugwood.org)
Management:
- Apply pre-emergent herbicides to help prevent seedling establishment.
- Post-emergent herbicides selective for grasses can be applied when plants are seedlings, but these are less effective once rhizomes have formed.
- Avoid cultivation, which spreads rhizomes.
