Buckeye Yard and Garden onLine

Last week in BYGL (Issue 2008-04, April 24, 2008), an article about dandelion and broadleaf weed control raised some questions that sparked some additional discussion on the BYGL conference call this week. As a result, some clarification is in order for this week.

The obvious presence of dandelions in yards can be seen throughout Ohio at the current time. In some yards, along roadsides and agricultural fields, carpets of bright yellow dandelion blossoms beg for attention and it would appear that this could be the best time to manage these perennial weeds. In the past, spring and early summer were the typical times of the year that treatments were recommended. However, the currently accepted best time of year to get the greatest impact out of broadleaf weed control treatments is the fall when perennials are moving nutrients back into their roots and thus will move more herbicides into the roots as well. Yet in some cases, broadleaf weed control can't wait till fall and requires treatment in the spring to reduce the number of potential seeds produced through the growing season. Large dandelion populations may require treatment in the spring to slow down their reproduction but will still be best controlled with a second treatment in the fall. As stated in last week's BYGL, the greatest impact of the early season treatment will occur at the puff-ball stage.

Another point that was raised was whether liquid or granular herbicide applications were more effective. The answer was that either can be equally effective if applied correctly. Liquid applications have the advantage of ease of application but the disadvantage of potential off-site drift. Granular applications are also easy to apply and have little or no drift problems, but if they are not applied when the leaves of weeds are wet, then most granules roll off the surface of the weeds and fall to the ground where they have no affect. Only the granules that get trapped in a leaf axel dispense their herbicide to the target, potentially a sub-lethal dose. The labels of all pesticides need to be read carefully to be sure they are applied correctly to get the best performance possible out of the chosen product.