I've been reading about microclover as a component of lawns. Have you heard of anyone using it in our area? Supposedly, the microclover has small unobtrusive leaves, and does not form clumps, but grown throughout the lawn. The idea is greatly appealing to me. Thanks. - Mike, Racine.
Clover in the lawn is not a new idea, but microclover is a new twist. Clovers and other small plants like wood violets were routinely included in lawn seed mixes prior to World War II. Dr. John Stier, Professor of Environmental Turfgrass Science at UW-Madison, and a UW-Extension Specialist, says that there were a lot of reasons to stop including broadleaf species in turfgrass seed mixtures and to start controlling weeds in lawns.
In addition to the aesthetic appeal of a uniform lawn, people wanted to eliminate plants like clover that attracted bees and dangerous plants like poison ivy. A uniform lawn is also desirable for recreational and athletic activities. Once broadleaf weed killers were manufactured and available for homeowners to use, turgrass seed mixtures changed significantly and our lawns became comprised solely of species and varieties of grasses.
Microclover is an interesting twist because the clover used is exceptionally small, so it is somewhat unobtrusive in the lawn. It does, however, still flower, so there is the bee attraction factor to consider. Because clovers are "nitrogen fixers," that is, they pull nitrogen from the air for their growth, you might assume that the neighboring grass would benefit from clover being in the lawn, but Stier says this is not the case.
"We've done studies with clover/grass mixtures. The clovers "fix" their own nitrogen through a symbiotic relationship with Rhizobium bacterium, but it's kind of like two strangers in a sandwich shop: the shopper with money buys a sandwich for themselves, but does nothing for the other shopper. Hence, in unfertilized lawns clover tends to dominate, usually becoming the dominant species in a few years. I see no reason why microclover lawns would be any different: trying to maintain a 50:50 mixture of the two species would provide a challenging maintenance opportunity. Applying nitrogen fertilizer will help the grass outgrow the clover; not adding fertilizer will allow the clover to grow at the expense of the grass."
So, microclover lawns might work for you as a low maintenance lawn alternative, but if you do not fertilize the lawn the clover will take over the lawn. If you do fertilize the grasses will take over because clovers, including plants like black medic and wood sorrel (those yellow flowering clovers), do not grow as well when nitrogen fertilizer is applied to the soil. Another consideration is that if you have other types of broadleaf weeds in the yard, you will not be able to use chemical weed controls without killing your microclover. Removing dandelion, wood violet, thistle, and other weeds would have to be done by hand.
For more information on lawn establishment, maintenance, aeration, and lawn alternatives for shady areas, go to the UW-Extension publication website at http://learningstore.uwex.edu and look at Dr. Stier's excellent series on lawn care. Publications can be downloaded and printed for free by simply clicking on the "View PDF" button.
UW-Extension Master Gardener volunteers serving as plant health advisers can help answer your questions at firstname.lastname@example.org or (262) 886-8451 at the Racine Horticulture Helpline.
Dr. Patti Nagai is the Horticulture Educator for Racine County UW-Extension. Submit your questions for the Journal Times Q&A column to Dr. Nagai at Patti.Nagai@goRacine.org and put "Question for RJT" in the subject line.