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Hort Update for Jan. 25, 2016

Lawns Major Symptom:

1. Salt damage

Stunting, leaf burn, root damage, and plant death near pavement

2. New Turf NebGuide

“Simplifying Soil Tests for Turf Professionals” by Bill Kreuser
Trees & Shrubs  
3. Snow loads on trees Let melt naturally or remove gently with a broom
4. Pruning storm damaged trees Safety first. Leave pruning of large trees to professional arborists.
5. Anti-desiccant, 2nd application Reapply to plants with a history of winter desiccation
6. Corrective pruning of shrubs and ornamentals Conservative removal of broken branches can be done now
7. Wildlife damage Protect trunks by encircling with hardware cloth; apply repellants
8. Pine needles and soil pH Pine needles making soil or compost too acid is a myth                     
Fruits & Vegetables  
9. Wait to prune fruit trees Best done in February/March
10. Dormant oil applications Apply on mild days before plants begin to break dormancy
Upcoming Events  
11. ProHort Education Program In-depth education for green industry professionals. Feb. 5 through March 25.

1. Salt damage to turfgrass growing near pavement where deicing agents are used does occur. High salt levels change the structure of soil, causing it to become compacted and restricting the availability of nutrients, water and oxygen to plants.  In summer, high salt levels decrease a plant's ability to absorb sufficient water, even when water is available.  Symptoms of salt damage include stunting, leaf burn, root damage, and plant death.  To help limit issues, use the smallest amount of product needed to manage ice.  Select products known to cause less soil/plant damage.  Avoid piling snow containing salt on turfgrass.  Consider mixing cat litter or sawdust into deicing products to reduce the amount used.  In runoff areas affected by high salt levels, flushing the soil with 2" of water over a 2-3 hour period in early spring may help leach salt from soil. Repeat this procedure 3 days later. If the soil is not well drained in the area, leaching will not work well. In cases with repeated and heavy deicing salt use, removing the top four to six inches of soil may be needed.

Winter Deicing Agents for the Homeower, Nebraska Extension


2. New Turf NebGuide - Soil tests can be a valuable tool for turfgrass nutrient management, but sometimes test results can be confusing. Knowing which soil test results are important can simply turf management. A new Nebraska Extension NebGuide titled: “Simplifying Soil Test Interpretations for Turf Professionals” helps with soil test information.  


3. Removing ice/snow loads. The best way to remove snow/ice from trees or shrubs is to let it melt naturally.  If there is concern about branch breakage, newly fallen snow can carefully be swept from branches using gentle upward strokes with a broom.  Before doing so, observe branches closely for signs of cracks or breaks before attempting to remove snow loads.  Do not hit branches with a broom or tool handle to knock snow off.  Remove enough snow to decrease the load; then allow the remainder to melt naturally.  Never attempt to break or shake ice off of a plant.  This is dangerous and likely to result in more, not less, branch breakage.  It could also result in cracks that may not initially be noticed; but could lead to branch failure during another wind/ice/snow storm.

Trees and Ice Storms, Nebraska Forest Service


4. Pruning to repair winter snow/ice damage Trees damaged by storms require immediate attention (removing low-hanging branches, clearing from utility lines, etc.). Homeowners need to be aware of safety issues and consider the best approach for dealing with a tree they are trying to save.  Chain saw work off the ground, removing branches that can’t be reached from the ground and other heavy work (essentially all work on large trees), should be done only by professional arborists.

The only pruning that should be done immediately is removing broken branches. Leave the fine pruning and finishing cuts until after the tree has been thoroughly evaluated. Pruning cuts made during winter months will dry out to some degree. Dieback of the inner bark around a pruning cut can be minimized if the final pruning is done just before the tree begins to grow in the spring. Have a trained arborist make the finishing cuts. Branches that have pulled away from the trunk should be removed at the bottom of the split. Avoid causing any additional damage to the trunk. Remove loose bark but do not cut into bark that is living and still attached. Never “top” trees. The International Society of Arboriculture defines topping as the “indiscriminate cutting of tree branches to stubs or lateral branches that are not large enough to assume the terminal role.” Topping creates serious hazards and dramatically shortens a tree’s life. Other names for topping are “heading,” “tipping,” “hat-racking” and “rounding over.” Never use paint or wound dressing to cover wounds. These materials interfere with the tree’s wound-closure process.

Source: Nebraska Forest Service Storm Damage Series # 1.


5. Anti-desiccant, 2nd application – Time for a second application of anti-desiccant on plants with a history of winter drying problems like arborvitae, holly and mahonia. Read and follow label directions. Have warm, soapy water nearby and clean out the sprayer immediately or equipment may be ruined by the product.  One common anti-transpirant available through nurseries and gardens centers is called Wilt-Pruf, but other products are available.

Winter Desiccation Injury of Trees and Shrubs, Oklahoma State University


6. Corrective pruning on shrubs and ornamentals – If shrubs have suffered damage, such as broken branches, during recent snow events those damaged branches can be pruned. Be conservative in your pruning at this time and only remove the broken sections. It’s hard to do your best pruning job in freezing cold temperatures standing in snow. It’s better to wait until warmer conditions arrive in late March to make the more permanent decisions about what should be removed. Better pruning conditions makes it easier for you to make good decisions, maximizing plant health and attractiveness.


7. Wildlife damage will continue to occur throughout winter and into early spring. Check mulch around trees and shrubs and pull it six inches away from trunks/stems.  Use cylinders of hardware cloth to protect young tree trunks from gnawing by rabbits or voles. Registered repellants can be sprayed on trees and shrubs to discourage feeding. Read all label directions and reapply repellants as recommended.

Prevent Wildlife Damage in Your Landscape, Nebraska Extension


8. Pine needles and soil/compost acidity. It is a common myth that pine needles will make soil or compost too acid.  It is fine to use or recommend the use of pine needles in compost; and wise to remind clients that the use of pine needles will not address issues with alkaline soil.  Fresh pine needles are very acidic, but once they decompose they are only slightly acid to neutral.  Also, in areas where pine trees have grown, pine needles tend to remain on the soil surface and do not readily break down due to their waxy surface and high lignin content.  If pine needles are used in compost piles, it is wise to chop them well before adding them to the pile; and use small amounts since they are slow to break down.


9. Wait to prune fruit trees until late February-March. The best time for pruning fruit trees for fruit production is in late winter, into early spring, depending on the weather. See the following publication for more information on fruit tree pruning.

Pruning Fruit Trees, Nebraska Extension


10. Dormant oil sprays are applied to control insects and mites overwintering on trees and shrubs. They need to be applied during dormancy to prevent damaging plants. Dormant oils are best applied as late in winter as possible, when overwintering insects are at their weakest, but before plants begin to break dormancy. Pests controlled by oil sprays include scales, aphids, mites and some overwintering caterpillars and eggs. Air temperatures need to be at least 40 degrees before applying dormant oils, with applications made fairly early in the day. If the spray freezes before it dries, plants can be injured. Follow all label directions and thoroughly cover branches and twigs for effective control.


11. ProHort Education Program is available to garden center employees, green industry professionals and anyone wanting to obtain in-depth information on landscaping, garden maintenance, and lawn care. A participant who attends all classes and passes a proficiency test will receive a certificate of completion of ProHort Education which can be displayed in their place of business.

Where: UNL Douglas-Sarpy Extension Central Office; 8015 West Center Road, Omaha

Cost: $440 for entire course, which includes the price of the handbook. Additional employees from the same company are $385. OR Per-session Cost: $60 one-day session. $30 per half-day session (please indicate morning or afternoon). This price does not include the handbook.

Feb. 5: 9 a.m. - 12 p.m. Basic Botany Sarah Browning, Nebraska Extension Educator, Lancaster County
Feb. 5: 1 p.m. - 4 p.m. Introduction to Soils Brad Jakubowski, Instructor, Doane College
Feb. 12: 9 a.m. - 12 p.m. Tree Basics Graham Herbst, Community Forester, Nebraska Forest Service
Feb. 12: 1 p.m. - 4 p.m. Tree Insects and Diseases Laurie Stepanek, Forest Health Management Assistant, Nebraska Forest Service
Feb. 19: 9 a.m. - 12 p.m. Bug Boot Camp Jonathan Larson, Nebraska Extension Educator, Douglas-Sarpy Counties
Feb. 19: 12 p.m. - 4 p.m. Vertebrate Pest Management Dennis Ferraro, Associate Professor, UNL
Feb. 26: 9 a.m. - 12 p.m. Introduction to Landscape Design Kathleen Cue, Extension Horticulture Program, Douglas-Sarpy Counties
Feb. 26: 1 p.m. - 4 p.m. Landscape Solutions Steve Rodie, Associate Professor, UNO
Mar. 4: 9 a.m. - 12 p.m. Home Fruit and Vegetables Connie Fisk, Nebraska Extension Educator, Cass County
Mar. 4: 1 p.m. - 4 p.m. Lawn and Landscape Management Scott Evans, Extension Horticulture Program Coordinator, Douglas-Sarpy Counties
Mar. 11: 9 a.m. - 12 p.m. Native Plants and Pollinators Natalia Bjorkland, Nebraska Exension Educator, Dodge County
Mar. 11: 1 p.m. - 4 p.m. Turf Grass Management John Fech, Nebraska Extension Educator, Douglas-Sarpy Counties
Mar. 18: 9 a.m. - 12 p.m. Introduction to Perennials Kelly Feehan, Nebraska Extension Educator, Platte County
Mar. 18: 1 p.m. - 4 p.m. Invasive Pests/Noxious Weeds Julie Van Meter, Nebraska State Entomologist
Mar. 25: 9 a.m. - 12 p.m. Pest Management Approaches Larry Schulze, Nebraska Extension Professor Emeritus
Mar. 25: 1 p.m. - 2:30 p.m. Pest Management Approaches Larry Schulze, Nebraska Extension Professor Emeritus
Mar. 25: 2:30 p.m. - 4 p.m. Containers Michaela Fortina Forst
Apr. 1 - SNOW DATE Make-up day for classes cancelled due to weather
Jun. 10: 1 p.m. - 4 p.m. Plant Diagnostic Clinic Nebraska Extension Team in Douglas-Sarpy Counties