Take control of lawn weeds in the fall

It has certainly been a year filled with weeds in many area lawns and gardens.   Many have been asking what to do to get control of these unwanted invaders.   The good news is that now is the time to take control of many perennial and winter annual weeds that plague our lawns on a yearly basis.  

Fall weed control actually has several advantages.  The cooler temperatures mean that the risk of damage to the lawn from the herbicide is low, and the risk of damage from drift is reduced as well since ornamentals are in the process of going into winter dormancy.  But the biggest advantage to fall weed control is that this is the time when weeds are preparing for winter by translocating food resources to the roots (storage areas).  Herbicides will also be translocated at this time and provide a more complete kill.

Perennial and winter annual weed control

Perennial weeds such as bindweed are a very pesky problem.  Bindweed seeds can survive 60 years in the soil which means this weed requires long term control.  Dandelions also pose a long term problem.  This weed is a prolific seed producer and it thrives in the cool weather of spring and fall.  Bindweed, dandelions, clover, plantain, and violets are all perennial weeds that should be treated in the fall.  Herbicide applications for these weeds should be made in October through early November depending on weather conditions. 

Winter annual weeds such as henbit and chickweed also germinate from seed in fall.  They overwinter as small plants about the size of a quarter. When spring arrives the weeds rapidly grow and flower.  Once these weeds reach the flowering stage in the spring, they are practically impossible to control. A fall herbicide application provides the advantage of killing many of these annual weeds when they are still small and easy to kill.

Keep in mind that research shows that herbicide applications on these weeds even after the first frost will still be effective.  Many fear that spraying after a cold snap or frost is too late, but that is not the case.   Try to pick a mostly calm day when temperatures will reach 60 degrees for the fall herbicide application to give the best results.

What to use

There are many options when it comes to herbicides.  There are as many as 13 different active ingredients out on the market.  It is generally recommended to use a herbicide that contains multiple active ingredients to get the most effective weed control.  Trimec, Fertilome Weed Free Zone, Ortho Weed B Gone, Bayer Advanced All-In-One Lawn Weed Killer and other similar products all contain 3 or more active ingredients.

Some active ingredients are better than others on certain weeds such as in the case of wild violets.  This hard to kill weed often responds best to a spray containing triclopyr.  This is why it is important to check the label or seek assistance if you need help with a very particular weed.

Be sure to read and follow the label directions on whichever spray is chosen.  Remember that a late fall application of herbicide may or may not show immediate results.  Earlier fall applications will curl and yellow the leaves of the weeds, while a later application (November) may not show results until next spring.