Cool-season turfgrasses such as Kentucky bluegrass and perennial ryegrass are now producing seedheads. This natural phenomenon is induced by daylength, but the intensity of seedhead production is affected primarily by temperature and is likely the cause of the above average seedhead production this year. Seedheads detract from the appearance of a lawn because they grow quickly and unevenly. Plus the seed stalk is tougher than grass blades so they do not cut cleanly except with the sharpest of mower blades. After mowing, the grass may appear a lighter green to yellow because of the exposed seed stalks. Turfgrass plants expend a lot of energy producing seedheads and thus turf density usually decreases during this time. Some cultivars may produce more seedheads than others so some lawns or patches of the lawn may have more seedheads than other areas. These seedheads need to mature on the stem for about four months, so the seedheads produced now will not germinate when they are mowed or if they are moved as mulch to the garden. The most effective way to control seedheads is through mowing frequent with a sharp mower blade. Do not set the mower lower during seedhead production as some recommend (unless you want to encourage weeds). Professional turf managers may use growth regulators to manage seedheads, but timing and rate of application must be extremely accurate and it’s too late to apply once the seedheads are visible. We expect the seedhead production to last only about a month so the problem should subside soon.
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