Winter dessication injury is common throughout Nebraska on lawns, evergreens and other plants.
If a Kentucky bluegrass or tall fescue lawn is not greening up in areas, this is very likely winter injury. If an evergreen looked fine going into winter last fall but is turning brown this spring from the top down or on the south or west side of the tree, this is winter injury.
Drought conditions last summer and fall caused many plants to go into winter stressed. That was followed by no snow cover, a number of above average temperature days, and many days of high winds. These extreme conditions affected even correctly watered plants.
During winter, plants continue to lose moisture from tissues, especially evergreen needles. Moisture is not replaced during winter as roots are not functioning in cold or frozen soils. Eventually, plant tissues lose enough moisture to dry out completely and die.
Over the summer, Kentucky bluegrass lawns may slowly fill in bare areas as they spread by rhizomes. Most tall fescue lawns are unlikely to fill in bare areas as they do not spread by stolons or rhizomes. Some fescue cultivars are rhizomatous, but these still spread slowly.
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Bluegrass lawns could just be left to see how well they repair themselves with correct irrigation and fertilization. Tall fescue lawns may need reseeding. The sooner this can be done the better as seedlings will not do well once hot temperatures arrive.
If a preemergent herbicide for control of weeds like crabgrass has already been used on the lawn, seeding now may not work. Check to see what herbicide was used. If it was Siduron or Tenacity (mesotrione), reseeding could be done now.
If not one of these, the site may not be able to be seeded until Aug. 15 to Sept. 15, which is the best time of the year to seed cool season grasses.
If seeding is done this spring, avoid applying postemergent herbicides for broadleaf weeds like dandelions as these can harm seedlings.
On evergreen trees, the most important thing to do is water deeply, 8 to 10 inches, when the soil is dry. The most important thing not to do is fertilize with nitrogen which forces a stressed tree to grow and stresses it further.
Wait until after June 1 to prune out any brown branches or removing trees. If only the needles are affected, but the twigs and buds are still viable, the tree might slowly recover over time.
If 50% or more of an evergreen tree has turned brown, chances are it will not recover and replacement will be needed.
If conditions remain dry, correct watering of turfgrass and trees this summer and next fall is the main practice needed to help protect trees from winter dessication next season.
Correct watering means wetting the soil deep enough and then not watering again until the soil begins to dry out. Overwatering is just as harmful to roots and plants as under watering.
Kelly Feehan is a community environment educator for Nebraska Extension-Platte County.