A Lawn Care Refresher
by Janice Hand

Somewhere under the snow lies a lawn, which will turn green again in the spring, whenever that may arrive. Looking ahead to the happy event, it’s time to check lawn care practices. I just learned (and re-learned) a few things that others may find helpful.

  • Dormancy is natural.  Our turf grasses in northern Illinois are “cool season” grasses. This type grows during the cooler months — spring and early summer and then again in fall. It is normal for this form of grass to go dormant in the heat of mid-summer, and watering it to keep it green can actually harm this type of grass. This form of grasses can be weakened by on again-off again watering during its “off” (dormant) season. Bottom line: do not water your turf during its natural dormancy period (unless there is a very severe drought, and then you should water, but only enough to keep the crown alive —about ¼ inch of water).
  • Mow at 2-3 inches.  So that grass plants can produce enough food via their green “leaves,” do not mow less than 2 inches high. A longer lawn better shades its roots to conserve water and roots are hardier since they have access to more food generated by the green leaves. Also, never remove more than 1/3 of the plant height during any one mowing, or the lawn will be stressed. (If the lawn gets very tall, split the mowing into 2 sessions a few days apart. The first one takes off the top inch or so, and the subsequent mowing takes off the rest.)

  • Leave clippings. Many people think that clippings promote thatch. Not true. Clippings are about 80% water, so will reduce to almost nothing. Thatch is made up thicker materials like stems and roots, not clippings.

  • Test soil. To make sure that your lawn soil is optimal, you can have a lab test it. To do that, wait until the soil is above 50°; take your sample 2-4 inches down (not at the surface); and take several samples around the yard, mixing them together to submit about 1 cup of soil for the test. (The U of I Extension can refer you to labs in this area.)

  • Treating salt damage. Most gardeners routinely spread gypsum to counteract road salt. However, gypsum only works if the “salt” is sodium chloride. Since Lincolnshire uses a mixture of calcium chloride, beet juice, and sodium chloride (the mixture depends on circumstances), applying gypsum is appropriate in our village.

  • Lawn problems can be diagnosed by “indicator weeds.” Prostrate spurge and knotweed grow in compacted soils, while creeping Charlie, violets, and nimbleweed grow in shady areas with poor drainage. Soils with poor fertility seem to generate white clover, and plantain.

  • Use herbicides for the weed stage.  Pre-emergence herbicides form a barrier and kill weeds as they come out of the seed. Because of that, if you use such a weed-killer, do not dig or cultivate after it is applied or you will break the “barrier” and allow weeds to come through. The best timing is late April/early May when the soil is about 55°. The other kind of herbicide is post-emergence – these kill broadleaf weeds when they are actively growing. Always read and follow label instructions exactly (technically, herbicide labels are a federal legal document!).

  • Fertilizing. There are two optimal times to fertilize a lawn, if fertilizing is needed. While it is not necessary to fertilize (esp. if leaving clippings to decompose and provide nutrients to the turf), some gardeners prefer to do so. The optimal time? Fall when the grass is no longer growing (you no longer need to mow) and the air is cool (about 45-50°). Late season fertilization feeds the roots, leading to early spring greening with flush growth.  Another good time to fertilize turf is early spring. (Just remember, do not buy fertilizers with phosphorus—make sure the middle number on the bag is 0.)

Understanding Grasses
by Ellen Strauss

Some of us are uneasy planting ornamental grasses, because we’ve seen such big out- of -control clumps in neighboring yards.  To understand why some spread and some remain in their place, one has to understand how grasses grow. All grasses, including lawn grasses, grow by means of creeping rhizomes (underground stems.) New shoots will arise at intervals along the rhizome as it pushes along under the soil. Some rhizomes grow quickly and the shoots are spaced at long intervals along it, this grass forms an interwoven mat or turf, and is very desirable for lawn grasses. Ornamental grasses may also have shoots at long interval spacing, which however may be undesirable, as they will spread rapidly and become unsightly, especially in the garden.

Grasses are also classified as warm season and cool season. Cool season grasses green up quickly in the Spring, and rest during the heat of Summer. Warm season grasses get a later start, however, stay green in the Summer heat, and flower in Autumn. 

Some examples of these running ornamentals grasses are:  Japanese Blood grass (Imperrata cylindrica), Chinese silvergrass (Miscanthus sinensis), Crimson fountain grass (Pennisetum setaceum), and Prairie Cord Grass (Spartina pectinata) all of which can become invasive and take over the garden.

Some grasses produce very short rhizomes with shoots stacked up one on top the next. These are clumping or bunching grasses which expand slowly and are much more desirable in garden plantings.

Some examples of bunching grasses are:   Big Blue stem (Andropogon gerardii), Side Oats Gramma (Bouteloua curtipendula), Blue Gramma  or mosquito grass (Bouteloua gracilis), Northern Sea Oats ((Chasmanthium latifolium), Purple Love Grass (Eragrostis spectabilis), Switch Grass(Panicum virgatum),and Little Bluestem (Schizachyrium scoparium.)  These clumping grasses are all native to Illinois, and are warm season grasses. Prairie Dropseed (Sporobolus heterolepis ) is a clumping grass of intermediate season.

For variety one might also consider grass-like plants such as Sedges (Carex spp.), or Rushes (Juncus spp.) in the mixed garden.

Sources:  1) University of Illinois Extension,  “Horticulture, Native Plant Series #3”

                2)  Horticulture Magazine. Oct./Nov. 2009 “Native Grasses” by William Cullina

                3)  U of I Extension web site:   http//web.extension.illinois.edu/lake/hort_env.html