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Spring's Dry Conditions
submitted by Sarah Browning, UNL Extension Educator
This winter eastern Nebraska has experienced dry winter conditions; February and March have continued to be dry. Is it time to apply water to your landscape? Here are a few considerations.
How Desiccation Injury OccursAlthough plants are dormant from October to March, they continue to lose small amounts of water through their leaves, stems or crowns. Water loss is hastened by high winds, dry air, warm temperatures, and reflected heat from buildings. Desiccation injury results when plants cannot replace water that is lost through leaves, crowns or stems during winter, either due to dry or frozen soil where water is not available for uptake.
Leaf scorch, needle scorch and twig dieback can result from dry conditions. Symptoms of leaf scorch are seen as uniform browning around the edges of leaves on broadleaf plants. If dry conditions continue the scorch expands into the leaf, resulting in dead tissue between the leaf veins.
Evergreen needles turn brown uniformly, beginning at the tip. Spruce needles may redden, especially in areas facing south and the upper side of branches. Brown, damaged foliage is often found on one side of the plant, either due to wind exposure or reflected heat from a hard surface.
In the landscape, this type of injury is usually most prevalent on needled or broadleaf evergreen plants, particularly arborvitae and boxwood, but sometimes also pine, spruce, fir, juniper and yew. Injury is less common on deciduous plants, but broadleaf trees and shrubs are especially prone to leaf scorch in the first 2 to 3 years after transplanting while their root system is reestablishing.
With dry conditions continuing, watering landscape plants is beneficial. Water only when the soil is not frozen and air temperatures are above 40 degrees F. Apply water at mid-day so is has time to percolate down into the soil before nighttime's colder temperatures.
Plants should receive one inch of water per week, either through irrigation or rain. This will provide them enough water to put on a full canopy of leaves this spring. So if rain doesn't come, plan to water trees. A deep soaking every 2 weeks is adequate for most trees in unirrigated landscapes.
Use a slow-running sprinkler and apply water deeply, moistening the soil to a depth of about 12 inches for trees and shrubs, and 6 inches for turfgrass. Apply the water slowly enough that it can soak in and does not run off. Use a long-bladed screwdriver or piece of rebar to check the depth of water penetration. Once you've reach dry soil, it will be much harder to push the probe into the ground. Apply the water slowly enough that it can soak in and does not run off.
If dry conditions persist, one or two irrigations per month would be beneficial.
Also, topdressing mulch around tree and landscape beds will help conserve soil moisture. Apply a 3-6 foot diameter ring of mulch around the base of trees and shrubs with 2-3 inches of an organic material, like coarse wood chips. But don't create any mulch volcanoes! Don't pile the mulch up against the tree's bark though, keep it at least 3 inches away.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office
Contact Information University of Nebraska-Lincoln
in Lancaster County
Web site: lancaster.unl.edu
444 Cherrycreek Road, Suite A, Lincoln, NE 68528 | 402-441-7180