During the hot summer months, leaf scorch is major issue that causes brown leaves to drop from trees prematurely. Organic lawn care products like Revive can help make your lawn healthier, but the most common problem contributing to leaf scorch is improper watering. Is leaf scorch a problem in your neighborhood? Learn more from the story below:
During the hot days of summer, many trees, shrubs, flowers and vegetables develop dry, brown leaf margins. The tissue between the main veins may also be affected causing leaf spots. In severe cases, entire leaves will turn brown or black and die. Some trees, such as aspens, are especially susceptible, but the condition may occur in many other species. Evergreens can also suffer leaf scorch in which the needle ends turn a light tan or pinkish color. If the condition persists, needles will turn brown or develop brown bands, and may drop off.
Both of these conditions are called leaf scorch, caused by a tree or shrub’s inability to take up sufficient water to meet its needs under harsh summer weather conditions. Water is taken up by a plant through its fine feeder roots and transported through the vascular system to the leaves. When it is unable to take up enough water, the leaf tissue that is farthest from the major veins will dehydrate first. That is why leaf margins scorch first.
Inadequate Roots. Most frequently, the problem is a root system inadequate to meet the plant’s needs. This may be due to: 1.) poor root growth due to being restricted by pavement as seen with the maple tree; 2.) root loss from tilling or construction; 3.) and application of a soil sterilant in the vicinity of the tree; 4.) drought stress; 5.) a loss of roots due to dehydration during a dry winter and spring; 6.) overirrigation or over-application of a fertilizer; and 7.) an injury or infection on the trunk or branches severe enough to interfere with the movement of water and nutrients.
• Excess Moisture. When a plant is over watered, it cannot grow new, waterabsorbing roots without oxygen. Soggy soils therefore prohibit root development and scorch will result. The combination of no soil moisture in the winter and spring, and too frequent watering in the summer will practically guarantee that leaf scorch will develop.
• Too Much Fertilizer. The overapplication of fertilizer can cause leaf scorch by ‘burning’ the roots. This damage may appear as either leaf spots or marginal leaf burns. The damage may show up on one sector of the plant, one limb of a tree or shrub, or the entire plant, depending on how much of the root system is damaged by fertilizer. Fertilizers are salts and soils with a salt level higher than the plant will also cause leaf scorch. Fertilizer spikes, that deliver concentrated salts at specific sites, can burn roots and contribute to leaf scorch.
Once leaf scorch has occurred, there is no cure. The dehydrated portions of the leaf will not turn green again, but with proper water management, the plant may recover.
During the growing season, water deeply and as infrequently as possible. This can be difficult when trees are located in or near lawns, but a deep and infrequent watering schedule will benefit your lawn as well, encouraging deep root development. Trees typically need less frequent irrigation than lawns do, but the two can coexist. Remember that roots need oxygen, and this means the soil must be allowed to dry out somewhat between watering.
Finally, if scorch occurs, resist the urge to continually apply more water. Just keep up with the deep and infrequent schedule. In some years, if conditions are especially hot and windy, some scorch is likely. Don’t panic and kill off your trees with an excess of kindness by over watering. —Read the full story at colostate.edu