The Master Gardener Articles

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Dandelions

Dandelions produce a beautiful flower in early spring, however most homeowners say enough is enough. Too much of a good thing often turns bad. Many homeowners over-react when they spot that first yellow bloom. Out comes the chemicals for the frontal attack. However since the dandelion is not actively growing (pushing out new leaves rapidly) your control will be minimum. Wait till the air temperature is between 60 – 75°F (generally mid May). The chemical will be rapidly absorbed through the leaves and transported to the roots, killing roots and all. Since the chemical is foliar absorbed, leaf contact by the chemical is essential. If rain is forecasted within the next 24 hours do not apply the post-emergent chemicals. For best foliar contact, when using a granular product, apply to dew moist foliage in the early morning. Within 24 hours you will see the top growth begin to curl. Within 4 weeks your lawn will be clear of dandelions. If you have seeds blowing in after you apply the chemicals or if some dandelions were missed you can reapply in early fall. (Late September to mid October)

The dandelions are actively growing again in the cool of the early fall. The herbicide is rapidly absorbed and is moved to the roots with the carbohydrates, as the dandelion gets ready for winter. Hot weather applications (July, August, and early September) are not very effective since the dandelion has hardened off and is not growing rapidly.  Since most herbicides used for broadleaf weed control are dependent on rapid weed development to assure a good kill, summer application are a waste of time and money.

For more information, contact George McVey, Union County Program Assistant, Horticulture and Master Gardener Coordinator at 937.644.8117 or by e-mail at gmcvey@ag.osu.edu.