Thomas J. Koske, Attaway, Denise | 9/11/2008 5:08:08 PM
A large dead area in the lawn can be expected when a recent hurricane or bad storm leaves a lot of debris. This dead area will occur wherever debris is piled up for several weeks. Usually it will be near the curbside where debris waits for collection by recovery services or normal waste management crews. When the pile is removed, it leaves a dead-grass “storm spot” in its place. The storm spot can occur with any type of debris, or if a tree with foliage falls and is left down, covering the turf for more than two weeks.
If the debris cover is over dormant grass in the cool seasons, turf death will take longer. Harshness of cover also depends on the density of the cover so that a pile of open branches is not nearly as lethal as a pile of leaves.
Louisiana grasses grow actively in the warm seasons and require light and air to survive. The grass will soon die without these two elements. It is unusual for large spots to repair themselves unless some rhizomes have survived. Bermudas and zoysias, with their underground rhizome stems, are very likely to have these structures pop up and recover the turf sward. St. Augustine, centipede and carpet grasses, however, have only stolons (runners).
What will come back in most cases where turf has died are weeds and other grasses from seed. Some aggressive turf species may run back in from the edges of the dead spots, but this kind of replenishment is not typical for larger brush piles. Debris removal within about two weeks in warm weather will reveal some etiolated, chlorotic (thin and yellow) shoots that are still alive. These may revive and grow with sunlight if they don’t burn off first. Also check below the brown leaves for healthy green stolons; if they're present, there is a good chance for a comeback.
Avoiding storm spots
You may be able to save the turf by managing the debris. If you create several small piles of debris -- rather than fewer large piles -- and take the trouble to push the debris to the left or right each week, no area will have debris on it for an extended period. When debris is moved, the declining spot gets a chance to recover. This requires a high degree of dedication on the part of the homeowner.
Piling debris in the street or drainage ditch in order to save the lawn is not a good avoidance strategy. Debris in the street blocks traffic, may damage passing cars, precludes street parking, can stop mail delivery and affects street drainage. Storm debris tossed into a drainage ditch is likely to cause drainage problems. In addition, organic matter placed in ditches and streams adds to water pollution.
If debris has sat in one place on the lawn for more that two weeks, chances are good that you will need to take deliberate steps to reestablish grass in the storm spot.
Seeding late in the growing season (after midsummer), is not a good way to reestablish the lawn. Research shows that seeding warm-season grasses after August will produce juvenile fall turf that will go into dormancy with great risk of not surviving winter freezes unless you are close to the warm-climate areas near the Gulf of Mexico.
If seeding is required, consider postponing planting permanent grass until late spring. Seeding Bermudas, zoysias, carpet or centipede should be done in mid-spring to early summer. At that time, kill off the weed vegetation, prepare a good seed bed and sow seed. Bermuda is the only grass that typically produces a good sod the first year; others will take about two years.
For recovery in late season or year 'round, planting vegetative material is the surest route. Solid sod is a popular and great choice, but plugs or sprigs are also options if you can stand the wait. Planting mature grass pieces is a more certain winter-surviving strategy. Pieces will be well-rooted to take off in the following spring.
When planting pieces of grass, you still need a good seedbed that is free of weeds. Press the sod or plugs to where their stolons (runners) are about level with the soil surface. This avoids a future lumpy lawn. Vigorous sprigs with roots also can be stuck into the ground to root. A good sprig has at least two active nodes (joints) and some roots. With sprigs and plugs, the closer you space them, the faster the coverage. Mow the plugs and sprigs regularly at the higher-recommended cut for that species.
If you're not solid sodding, watch for weeds in the fall and following spring. A preemergent herbicide appropriate for your grass can keep weeds at bay and may keep the spot weed free all winter. Otherwise, consider a postemergent herbicide cleanup in mid- to late-spring.
Photos of storm spots