Sunday, August 23, 2015

Fall is the Time to Manage Dandelions by Rebecca Anderson

 
Everyone recognizes a dandelion (Taraxacum officinale) by its bright yellow flower that transitions to a white puff ball in a matter of days. Most homeowners consider the dandelion an enemy of the perfect lawn.   A single plant can produce 15,000 seeds and those seeds can travel 100 miles with the proper gust of wind.  The plant is a perennial, meaning it will come back year after year once it is established.  This can make controlling dandelions a difficult task.

Dandelions are broadleaf weeds that can be managed with the herbicides 2,4D; MCCP (mecoprop); and dicamba (Banvel).  Many general-purpose herbicides available to home owners contain a mixture of these active ingredients.  Be sure to read the instruction label before handling any herbicides.  The best time to apply for control of dandelions is early September to early November.  The plants are busy storing energy for winter and will carry more of the chemical into the roots at this time of year.

Here are some additional guidelines for applying herbicides:

    • Apply to actively growing, preferably young weeds.
    • Do not apply herbicides when the soil moisture is low and weeds are drought-stressed; an actively growing, healthy, non-stressed weed is the easiest one to control;
    • Apply herbicides on a calm, clear day when the air temperature is between 50 and 85F; applying when temperatures exceed 90o F increases the potential for volatilization injury to other plants in the landscape;
    • Don’t apply if rainfall will occur within 12 hours; avoid applying irrigation for at least 12 hours following a herbicide application;
    • Don’t mow the lawn for 2 days before and after the herbicide application;
    • Do not apply to new turfgrass seedlings until the grass has been mowed at least three times;
    • Delay applying a broadleaf herbicide to new sod for 4 to 5 weeks after planting. 

    If you prefer to keep your yard chemical-free, managing dandelions is a much more physical endeavor.  The plant has a very deep taproot that should be removed.  Keeping the flowers from going to seed will slow the spread while repeated diggings may be needed to completely remove the mature plants. 

    For more information on weed control in your yard, see the following website:  http://www.cmg.colostate.edu/gardennotes/552.pdf