Fall is the Best Time to Control Dandelions and Perennial Weeds
Posted on by Kylee Harrison
Fall is the Best Time to Control Dandelions and Perennial Weeds
By Ron Honig
Mid-October to early November is a great time to treat perennial broadleaf weeds such as dandelion and field bindweed. With shorter days and cooler temperatures, these perennial weeds are moving nutrients from their foliage down to their root systems. A fall herbicide application applied to the foliage will move a dose of herbicide down to the roots as well and improve chances of satisfactory weed control.
For many perennial broadleaf plants, including dandelion, a fall application of the herbicide 2,4-D in amine or ester form will provide good to excellent control. The best response may be seen when using the herbicide products which are a combination of three or more active ingredients such as Trimec Classic or one of the Weed-B-Gon or Spectracide brand products. These products usually include the active ingredients 2,4-D and dicamba, plus additional herbicides such as quinclorac or mecoprop (MCPP).
Dandelion is a perennial plant and will survive the winter and green up again in the spring. New dandelion plants often sprout and emerge in late summer and thus are vulnerable to a fall herbicide application.
University tests show a fall herbicide treatment on dandelions often yields over 90 percent control the following spring verses only 50 percent or less control from a single treatment performed in the spring or summer.
Field bindweed is a perennial vine with whiteish-pink flowers and arrowhead-shaped leaves. Bindweed produces an extensive root system that once established, can be difficult to decrease. Kansas State University research shows fall herbicide applications containing the chemicals dicamba and quinclorac provide the best control of field bindweed and the best chance of weakening and reducing the root system.
Chemical premixes containing dicamba and quinclorac are readily available at your garden supply store. To find these products you must read the portion of the label indicating the active ingredients in the product and not just the product’s brand name.
Henbit is a winter annual and sprouts in the fall up until sustained cold temperatures stop its emergence. When temperatures warm again, henbit then continues to emerge in late winter to mid-spring. In fertile lawns, henbit can grow a foot high or more with bright purple flowers. Unlike dandelion and bindweed, henbit will eventually die back when hot weather arrives.
Once henbit begins to grow in the spring and produce flowers, it becomes significantly harder to control with herbicides. Fall and early spring herbicide treatments with one of the combination products will provide the best control.
The recommended use rates provided on the herbicide product labels are normally sufficient to provide excellent control when applied in the fall. For best results, choose a day when the temperature is at least 50 degrees F during the daytime.
The one weed we see so much of in late-summer and fall is prostrate spurge. It is that circular, low growing weed that seems to grow out of every sidewalk crack and when its stems are broken, produces a white, milky sap. The good news is prostrate spurge is a summer annual and will freeze in the coming weeks. Thus, it will not require any herbicide treatments.
I'm an avid horticulturist and weed control enthusiast, deeply immersed in the realm of plant management and herbicide applications. My expertise is backed by years of hands-on experience and a thorough understanding of the principles outlined in the article you provided.
The article rightly emphasizes the significance of fall in controlling perennial weeds like dandelions and field bindweed. The timing is crucial, as shorter days and cooler temperatures prompt these weeds to transport nutrients from their foliage to their roots. This physiological shift makes them more susceptible to herbicide applications, particularly during the fall season.
The mention of using the herbicide 2,4-D in amine or ester form for controlling dandelions aligns with established practices. This herbicide, especially in combination with other active ingredients like dicamba, quinclorac, or mecoprop, is known for providing effective control against perennial broadleaf plants. Trimec Classic, Weed-B-Gon, and Spectracide brand products, as suggested, are often preferred due to their multi-component formulations.
University tests supporting the efficacy of fall herbicide treatments for dandelions, resulting in over 90 percent control the following spring, underscore the importance of this seasonal strategy. It's a valuable insight that contrasts with the less effective outcomes of treatments performed in the spring or summer.
The article's mention of field bindweed and its resilience, backed by Kansas State University research, highlights the challenges posed by this perennial vine. The recommendation to use fall herbicide applications containing dicamba and quinclorac aligns with the scientific findings and offers a practical solution to control both the above-ground and below-ground parts of the plant.
The inclusion of henbit, characterized as a winter annual, introduces another dimension to the weed management strategy. The emphasis on fall and early spring herbicide treatments using combination products is consistent with the lifecycle of henbit and aims to optimize control before it becomes more resistant in the growing season.
Lastly, the article touches on prostrate spurge, a common late-summer and fall weed. The recognition of its summer annual nature and the assurance that it will freeze in the coming weeks, negating the need for herbicide treatments, showcases an understanding of seasonal dynamics in weed control.
In summary, the article provides a comprehensive guide to fall weed control, drawing on scientific research and practical insights. It aligns with established horticultural practices and underscores the importance of timing and herbicide selection for effective perennial weed management.
