Question
I'm getting more and more white clover on my lawn.  I've tried Scotts weed and feed but no change.  What can I do to get rid of it?

Answer
Hi Lou,

Using a POST-EMERGENT herbicide product to eradicate CLOVER may require several applications since this type of chemical only works through the mature existing plants.  Seeds from previous generations can remain in the soil to cause more new plants; so you may need to spray several times until the population is either under control or eradicated.

About CLOVER as a Weed.

Some people like to have a clover patch and wouldn't think of it as a weed.  Clover ("Trifolium" Genus with more than 300 species), like all legumes lives with a "Nitrogen-fixing" bacterium in its roots so it can remove nitrogen from the air in the root zone.  This is good because it contributes to soil fertility.  Sometimes a farmer will rotate his crops year by year and have a season with clover only to boost the nutrient nitrogen in the soil.
This same process contributes to an increase in nitrogen in soils wherever trifolium plants grow.

Clover growing anywhere is not an indication of Nitrogen problems as some might suspect;...it just indicates that clover seeds have been introduced to the area.

As with many weeds, it just takes one plant to produce hundreds on new ones. It likes cool weather and some types will fade back or vanish when the heat arrives, leaving seeds to sprout when temperatures are just right later on. Some species are very low growing and can produce lots of seeds which will fall to the ground to make a dense patch. Clover seeds are usually rather large compared to many plants so their seeds do not get blown around much, so growing patches of denser areas is the norm as new seeds fall to the ground near parent plants.

If you use a lawn mower that collects the lawn clippings, you will remove a lot of the flowers and seeds as you mow and this will help to control weedy trifolium.

Keep any weed from producing and dispersing its seeds and you will be doing much to reduce its populations on your property.

CHEMICAL CONTROLS:

Clover is a BROAD-LEAF type of weed.  Chemicals sold at your garden center may list the name
"clover" or "Trifolium" on the label IF these types of plants are TARGET WEEDS for the  chemical. Another rather common weed called "MEDICAGO" may be listed on an herbicide label; any chemical which can control weedy Medicago will probably also work on clover. Read the labels and follow directions.  Note that weather conditions can greatly affect the efficacy of an herbicide, and several treatments may be required.

Use POST-EMERGENT Chemicals on weeds already visible.

To control the broad leaf weeds (Dandy-lions, Henbit, Chickweed, clovers etc.) a post-emergent herbicide product that contains a mixture of the following three chemicals is recommended:

2,4-D (often sold and used individually as "Weed-B-Gone" formulations)
MCPP (Mecoprop)
Dicamba.

You should be able to find these chemicals or slight patented variations and mixtures of these at most lawn and garden/farm centers in either a granular (spreadable) or liquid (sprayable) product form. Sprayable forms seem to work best especially when weeds are young. March to late May is the usual time to find these weeds, although with a mild winter they can pop up much earlier, go to seed and be more of a problem, so keep an eye out for an invasion and spray accordingly.
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Use a PRE-EMERGENT HERBICIDE regularly and as directed with the product and weeds will never have a start. This is THE most efficient method to be weed-free. Note that you must suspend the use of this type of chemical whenever you re-seed with a wanted grass seed so plan ahead.

List of eight Pre-emergent chemicals by their Brand Names:
Dimension
Gallery
Pennant
Pendulum
Surflan
Snapshot
Treflan
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With a very thick and dense patch of weeds which has "choked-out" your wanted lawn grass, use a chemical like Monsanto's "ROUND-UP." This chemical (Glyphosphate) will work great and leave a dead area which you will have to re-seed or sod with turf grass.
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In summary spray kill what exists, work to prevent future invasions by keeping seed heads down and start using a PRE-EMERGENT chemical in the mid-winter and early spring to keep many early cool season weeds from even getting started. With dense patches, you may have to re-seed your turf grass after a eradicating the clover patch.

Look for the technical name "Trifolium" on herbicide labels or use it in web searches at GOOGLE.com for the best control data concerning Trifolium clovers and their relatives.

Another excellent web-site for information and images for about any and all types of plants is the USDA National Plants Database:

http://plants.usda.gov/index.html


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I Hope this has answered your question(s)!
Have the best Summer ever!

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