Question
How can I kill dollar weed that is coming up in my Kentucky Blue grass. We are in Hilton Head South Carolina and I am resending the question as requested without marking the "private" box. S

Answer
Good to see you again.  So you've got Dollarweed?

First tip: DO NOT mix up 'Dollarweed' ('Hydrocotyle umbellata' to botanists -- we Yankees know it as 'Pennywort') and Ground Ivy.

Perennial problems.  Two different plants.  Two different problems. To a casual observer, they can look like the same Weed.  Confirm via the North Carolina State University Center for Turfgrass Environmental Research & Education:
www.turffiles.ncsu.edu/Keywords/pennywort.aspx#IS004116

Next:  Different turfgrasses call for different solutions to Dollarweed eradication.  If yours was a St Augustine Lawn, you could manipulate the irrigation schedule and water less.  That treatment simply dries up the Dollarweed roots, and boy is it effective.  After all, this is a moisture-loving perennial Broadleaf Weed that NEEDS moisture to survive.  Its need for H2O is SO acute in fact that it is considered an 'Indicator Weed' -- a reliable sign your Grass is way too wet for its own good.  Thanks to the desert conditions in California, Dollarweed is nowhere in sight on the West Coast.

Unfortunately, your Dollarweed is growing in Kentucky Bluegrass.  KBG is nowhere nearly as tolerant of drought.

The best control of this and other Broadleaf Weeds is probably out of your reach.  But it works beautifully.

Got sheep?

Me, neither.  But that's the solution.  Straight from the offices of the National Center for Appropriate Technology, where they studied this.  The report states: '"Weedy" species are grazed at the same intensity as "good" species.  Because the growing points on Grass plants are located below the normal grazing level, high density stocking favors Grass growth.  The growing points on broadleaf Weeds are higher and are grazed off. This sets up a competitive advantage for Grasses.  Broadleaf Weed populations tend to decrease under intensively grazed systems.'

Yes, Sheep, not goats, will control Pennywort/Dollarweed, they claim.  Goats 'are good at cleaning up brushy Weeds.  Sheep prefer broadleaf forages to Grass, graze closer to the ground, and can be grazed on the same pastures with cattle.'

Unconventional, yes.  Maybe (as with my neighborhood) illegal as Zoned.  But it works VERY well.  'Even noxious, introduced Weeds can be controlled and eventually eliminated by repeated, intensive grazing through species such as sheep or goats.  These animals have mouth parts that can graze close to the ground, and they exhibit broad forage preferences.'

Here's the URL:

attra.ncat.org/attra-pub/pastures_organic.html

Corn Gluten Meal is not an option for Pennywort control.  CGM works on germinating Seeds, not on plants.  You've got a perennial Weed that overwinters.  When the plants sprout in Spring, they're not germinating; that's already been taken care of.  CGM will of course keep NEW Dollarweed SEEDS from sprouting.  But you want to remove the plants, too.

Which brings us to a study pitched last year to the Michigan Turfgrass Association by Dr Suzanne Lang, Associate Professor at Michigan State University, titled 'Organic Control of Broadleaf Weeds'.

Dr Lang wanted to find out how good a mulch made out of fallen Maple leaves would be at controlling Weeds.  Lang knew there was concern at one time about using deciduous leaves off a Maple tree for mulch 'due to possible alleopathic properties of some plant tissue.'

Back in 1999, Thomas A. Nikolai and Paul E. Rieke ran a study to find out whether chemicals in Maple leaves had those 'alleopathic properties' to keep out competition.  The answer was no -- Mulch made of Maple leaves caused 'no apparent deleterious effects to established Turfgrass.'  They predicted, however, that Maple-mulched Lawns would also have 'fewer Weeds than plots treated with Oak leaf mulch or plots that received no leaf mulch (controls).  Thus, Maple leaf mulch appeared to have potential as an organic herbicide.'

What they were saying was that Maple leaf mulch would not harm the Lawn.  But it WOULD damage growth of Weeds.

Later studies indicated that Maple leaf mulch would provide 81 percent control of Dandelions, a broadleaf Weed.  Dr Lang wants to isolate the natural chemical in those Maple leaves that is so good at stopping Weeds.  If you don't want to wait for the study, find yourself a Maple Tree and compost this season's fallen leaves.  Then cover your Lawn with them.

For less enlightened homeowners, there's the advice pitched by the Weedalert.com website, which is geared to Lawn professionals:

www.weedalert.com/weed_pages/wa_dollarweed.htm

Weedalert posts a chart of ways to chemically annihilate this ubiquitous pest:

www.weedalert.com/cgi-bin/recs_view.cgi?weed=30

How effective they are at that, I cannot say.

Me, I prefer to do things the old fashioned way, sans Agent Orange, so that we can watch our dogs roll around in the grass with no fear of genetic tampering or long term liver disease.  Birds can sift through my Grass for bugs and still produce healthy offspring with 2 wings, 1 head, etc.  The Soil structure likes it, too -- microscopic flora and fauna that would not survive a chemical attack thrive and complete Nitrogen and Carbon cycles in our yard year round.

As you see less of this plant around the Lawn, reach down and pull it up.  It will be hard to get all the roots, but not impossible.  Keep trying, and you will eliminate the Dollars and all the other broadleafed Weeds in your yard.

THE LONG ISLAND GARDENER