Q. I ran across an interesting product called Miniclover and would like to know if it would be a good addition to western Pennsylvania lawns. Are there situations where you might want to grow it instead of grass?

A. White clover used to be a very common component of grass seed mixes because it is a legume. Most legumes can transform atmospheric nitrogen into forms that plants can use. The process takes place in nodules on the roots of legumes that are formed by Rhizobium bacteria. Since nitrogen is the nutrient that lawns require most, it makes sense to plant grass seed with a compatible legume that can supply some of that nutrient. It may allow you to use less fertilizer.

When broadleaf weed killers came into widespread use in the 1950s, clover fell out of favor in grass seed mixes because it was damaged or killed by those products. Also, white clover creates large clumps that inhibit the growth of desirable grasses, which some homeowners found objectionable. White clover is also very attractive to bees, which makes some people nervous. As a result, white clover went from being a useful part of low-maintenance lawns to a problem weed.

Miniclover is a selection of white clover that is about half the size of the straight species and reaches only about 4 inches tall. It is less competitive with lawn grasses and does not form clumps when seeded at the appropriate rate.

A similar small white clover, microclover, has been trialed at the University of Maryland with good results. Microclover performed best when planted at 5 to 10 percent by weight with Kentucky bluegrass and turf-type tall fescue. Microclover has a dark green color that made lawns appear darker, which most people find more attractive.

It tended to overwhelm hard and Chewings fescues, but it may be that lower seeding rates of microclover would have been more successful. More research is needed.

Microclover did not perform well in shade at the University of Maryland trials, so researchers suggest it be used only in full sun situations. It is reasonably drought-tolerant but was damaged by severe drought conditions during the trials. Since microclover dies to the ground in winter, it probably is not suitable as a total replacement for lawn grasses here.

Also, like standard white clover, microclover is damaged by broadleaf weed killers, so other weeds that crop up in lawns seeded with microclover would have to be treated carefully. More research is needed to determine if certain broadleaf herbicides are less damaging than others. Cultural practices such as mowing at 3 inches and maintaining proper soil pH and fertility go a long way toward minimizing weed infestations in any lawn.

Microclover helps with weed control by shading out germinating weed seeds. Another big benefit is reduced nitrogen fertilizer applications, perhaps by as much as 1 to 2 pounds per thousand square feet annually. Given that runoff of nitrogen fertilizer is a serious pollutant in our waterways, using a less aggressive type of clover in lawn seed mixes makes a lot of sense.

Microclover and miniclover benefit from being inoculated with Rhizobium bacteria. They are usually sold as coated seeds, which consists of limestone, adhesive and the appropriate bacteria strain. Anyone who has ever grown beans or peas is familiar with the inoculant sold for those crops. This is similar but specific to these clovers.

Send questions to Sandy Feather by e-mail at slf9@psu.edu or by regular mail c/o Penn State Extension, Energy Innovation Center, 1435 Bedford Ave., Suite A, Pittsburgh, PA 15219.

First Published: May 20, 2016, 2:05 p.m.