Annual vs Perennial Weeds
Weeds can be grouped according to their life span: annual or perennial. In general, annual weeds grow from seeds from the previous growing season while perennial weeds grow from established roots that survive winters. From the standpoint of chemical control, the grouping is most important because pre-emergent herbicides are only effective for control of annual weeds.
Crabgrass and henbit are examples of annual weeds - crabgrass being a summer annual and henbit being a winter annual. Preemergent herbicides must be applied according to the expected date of emergence for each targeted species.
Perennial weeds live more than one year and recover or regrow from dormant stolons, rhizomes or tubers as well as from seed. Control of perennial weeds requires a post-emergent herbicide during its season of active growth. Effective chemical weed control requires identification of the weeds as to its classification (grass, broadleaf,sedge, etc.), life span (annual or perennial) and season of active growth (cool season or warm season).
Effective chemical control also requires accurate timing of applications, proper rate of application and uniformity of application. Always follow label directions for the product and observe all warnings and precautions relative to safety of the application.
Product names are included solely to help locating and identifying the herbicides suggested. Degree of control will depend upon herbicide rate, application timing, amount and timing of rainfall, soil type and infestation levels of the various weeds.
Grassy Lawn Weeds |
Broadleaf Lawn Weeds |
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| Perennial | Annual | Perennial | Annual |
Bahiagrass Carpetgrass Dallisgrass Johnsongrass Kikuyugrass Knotgrass Nimblewill Orchardgrass Quackgrass |
Annual Bluegrass Barnyardgrass Crabgrass Fall Panicum Foxtail Goosegrass Sandbur |
Broadleaf Plantain Buckhorn Plantain Speedwell Oxalis Speedwell Curly Dock Dandelion Dichondra Dollarweed English Daisy Ground Ivy Lespedeza Mary's Weed Moneywort Wild Violet White clover |
Buttonweed Burweed Carolina Geranium Carpetweed Chickweed Clover Cranesbill Cudweed Henbit Knotweed Lambsquarters Pigweed Purslane Speedwell Spurge Star of Bethlehem |