Nimblewill – Grassy Perennial Weed

Difficult Grassy Weed in the Landscape

As the garden renovations continue in my yard, the lawn has to be renewed too.  The problem is the grassy perennial weed know as nimblewill.  This lawn weed is quite at home in moist, shady locations, but it can tolerate sunny conditions too. 
The plant produces thousands of seeds, and mowing will assist in the spread of this warm season weed.  As this clump grows, the stolons that rest on soil, will root and produce another plant.

Nimblewill does not last in cool temperatures. As the stems and stolons die in the fall, patches of this lawn weed will appear as brown or tan sections in the grass.

Pulling nimblewill is fairly easy, as the roots are shallow.  However, broadleaf weed killers have no effect on this grassy weed.  The active ingredient in Roundup®, glyphosate, is effective. But glyphosate will kill anything it is sprayed on, including your prize perennials or ‘good grass’.  A new product call Tenacity, a herbicide by Syngenta, has been approved for use on cool season lawns.  Tenacity's active ingredient is mesotrione and can control 40 weeds, both grassy types and broadleaf types. 

Due to the wide spread of nimblewill in our lawn, we felt pulling it or even scraping it out was more than we could handle.  So hubby brought out the Roundup® , a non-selective herbicide, and these brown patches are evidence of its effectiveness.  (Yes, this was all nimblewill!)

Nimblewill had become a real eyesore in our lawn. Given a few years of taking over large parts of the yard, this grassy weed had to go.  Had we taken steps earlier, we may have been able to simply pull the small patches. 
As an organic gardener, I have relied on cultural methods to control weeds and insects in the garden.  So I’m really paying for ignoring the spread of nimblewill over the last few years. Before I completely lose any credibility I  have gained as an organic gardener, let me describe the cultural prevention methods and maintenance that will lessen the need for harsh chemicals.
Moist, shady locations are ideal for nimblewill. Removing the moisture by regrading or installing tiles will go a long way to reduce the dampness. Applying organic materials like organic fertilizers or compost to loosen the soil will help to absorb moisture better.



Shade can be reduced by limbing up trees to allow more sun to penetrate the area so soils can dry out.


Lawns that are thick will make weed seeds more difficult to take hold.  Feeding with organic fertilizers and watering deeply are two keys to a healthy lawn. 

Our next step will be to rake in a layer of compost, and then use the same grass seed blend we used on the bare areas. (Here the seed has started to sprout, and is filling in well.)

Nimblewill has been here too long, and I’m happy at its demise. 
Do you have any lawn problems?  Share your conflict with us.  Thanks.