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Hort Update for Dec. 15, 2015

Lawns Major Symptom:

1. Avoid traffic on frozen turf

Ice crystals can rupture and damage plant tissue

2. Vole damage potential/control

Damage to turf appears as 1 to 2 inch wide surface runway
   
Trees & Shrubs  
3. Winter watering May be needed if temperatures warm and moisture lacking
4. Anti-transpirants Reduce water loss leading to winter desiccation and browning
5. Wrapping trunks Only recommended during winter for thin-barked young trees
6. Pruning evergreens Limit amount when doing this for holiday decorations
   
Landscape Ornamentals  
7. Prevent early growth of spring bulbs Applying several inches of mulch will help keep soil cold
8. Pruning roses Objectives for late fall or early winter pruning        
   
Fruits & Vegetables  
9. Inspect stored fruits and vegetables Watch for signs of rot
10. Wait to prune fruit trees Best done in February/March
11. Plum pockets & peach leaf curl control Now is the time for dormant applications for good control
   
Miscellaneous  
12. Winter storage of pesticides and fertilizers Read and follow label directions for safe storgae conditions
13. Tool cleaning Routine maintenance prevents rust and lengthens the life of your tools

1. Avoid traffic on frosted/frozen turf - Foot or vehicle traffic on frosted turf can cause ice crystals on and within plants to fracture and damage plant tissue. This leads to cosmetic damage; resulting in foot prints, pathways or tire tracks across the turf that do not recover until late spring. Unlike actively growing grass, dormant grass will not recover until after growth resumes. This is one reason early tee times during late fall, winter and early spring are delayed until after frost has melted. Also keep this mechanical damage in mind during spring if a customer asks why a strip of turf is not doing well. Ask the client if any regular foot or vehicle traffic may have occurred in the area.

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2. Vole damage potential and control - Voles scar lawns by constructing runways and clipping grass close to the roots. The runways consist of closely clipped vegetation, about 1 to 2 inches wide. Small holes lead to underground runways and nesting areas. The damage usually is not permanent, but may detract from the lawns appearance. Vole damage to lawns is most likely to occur during winters when there is snow cover and a shortage of preferable foods. And when vole populations are high. If control is warranted, a combination of habitat modification and trapping is recommended. See control information in the “Controlling Vole Damage” NebGuide.

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3. Winter watering of trees and shrubs can be beneficial during times of warm winter temperatures and a lack of precipitation/snow cover. When watering, the soil should not be frozen and air temperatures need to be above 40 degrees Fahrenheit. Irrigation should take place early in the day so moisture soaks into the soil to avoid ice forming over or around plants overnight. Water just enough to moisten the soil six to eight inches deep. One or two irrigations during winter should suffice. Mulch trees with a two to four inch layer of organic mulch in a 4 to 8 foot diameter ring around the trunk to conserve soil moisture. If conditions remain warm and dry through winter and into spring, it will be most important to begin irrigation as soon as soils thaw in spring. Not everything needs to be watered. The priority for winter watering is young plants first - those planted in the last year and especially those planted this past fall, and then evergreens, particularly those growing in exposed locations and near the south sides of buildings.

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4. Anti-transpirants can help plants endure stressful periods. The most common types are an emulsion of wax, latex, or plastic that forms thin films on foliage to minimize water loss from plants. We recommend their use on evergreen conifers or broadleaf evergreens growing in stressful sites and usually during winter only. They can benefit newly transplanted trees. Select the right product for the plant species as there are toxicity issues. Read and follow label directions. Apply them once every six weeks in mid to late November, early January, and mid to late February. Avoid covering plants so much they become sticky with needles glued together. 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.

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5. Wrapping trunks: pros and cons - Sunscald commonly occurs on young, tender barked trees, such as Maples, during winter. It may be due to uneven heating of the trunk; however, there appears to be a correlation to root damage caused during transplanting. Proper planting and post planting care may be more important to protecting trees from sunscald than tree wrap. If used incorrectly, or left on too long, tree wraps can cause more harm than good.

If used, tree wraps should be attached no earlier than November. Begin at the soil line and wrap the tree upward to the first set of branches with the wrap overlapping. Always remove tree wrap in spring. Leaving trunk wrap on too long may girdle or compress the trunk, reduce photosynthesis, and increase insect (borer) damage. Avoid the use of paint as these may cause chemical damage to the trunk.

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6. Pruning evergreens for holiday decoration - Cutting greenery from landscape evergreens can help ensure freshness. Cutting evergreens to use for holiday greenery is pruning. It is important to use clean, sharp tools and to make well placed, evenly distributed cuts. This is not the ideal time to prune, so do not harvest too much.

Pine, fir and cedar are good to use for indoor decoration. They dry out slowly and hold their needles best at warm indoor temperatures. For safety, be aware the red berries of Japanese yew are poisonous and so are the green needles. Avoid the use of this greenery or be sure to keep yew greenery out of reach of children and pets. After the holidays, do not discard Yew greenery where cattle or horses might eat it. Even small amounts of Japanese yew greenery can kill a large animal.

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7. Prevent early growth of spring bulbs by applying several inches of wood chip mulch to keep the soil cold. Mulch will slow the warming of soil during winter and help prevent early growth of bulbs in spring that may be damaged by normal spring freezes. 

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8. Pruning roses and winter protection - Roses may be pruned in late fall for several reasons, 1) remove dead branches, 2) to reduce plant height so a rose cone can be used to provide additional winter protection, or 3) to reduce plant height of tall roses and prevent damage from winter wind.

Prune out dead stems or branches anytime they are found.

Reduce the height of tall canes above 30-36 inches to reduce breakage by strong winter winds. Tie the remaining canes together to provide additional support.

If rose cones are to be used for winter protection of hybrid tea roses, cut stems back only as much as is needed to fit the cone over the plant.

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9. Inspect stored fruits and vegetables (for example; pears, apples, winter squash, parsnips) for signs of rot.  As with ornamental bulbs, fruits and vegetables that can be stored indoors during the winter months are susceptible to rot if not properly cared for. The University of Nebraska, Lincoln has a great publication on proper storage of fruits and vegetables. 

Storing Fresh Fruits & Vegetables, Nebraska Extension

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10. 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

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11. Plum pockets & peach leaf curl are caused by Taphrina fungus. Dormant sprays of fungicides are effective controls if applied in late fall or late winter before buds begin to swell and when temperatures are above 40° F. These diseases cannot be controlled once leaves have started to expand or leaf symptoms appear. Use the fungicides ferbam, clorothalonil (Daconil), Bordeaux or liquid lime-sulfur. Do not add oil to lime-sulfur or spray oil treatments for three weeks after application of lime-sulfur. Lime-sulfur should not be applied to trees when temperatures are below 45 or above 80 F. Follow recommended label rates for all commercial fungicides.

Peach Leaf Curl, Nebraska Extension
Peach Leaf Curl and Plum Pockets, University of Kansas

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12. Winter storage of pesticides and fertilizers - For safety, it is important to read and follow label directions for storage of pesticides. Pesticides and fertilizers should be stored properly for winter. Most pesticides should be kept from freezing, and also away from sunlight, open flame and excessive heat. All this information is on the label. Keep pesticides and fertilizers sold in bags or cardboard cartons away from moisture. Also make sure all opened packages are well sealed. Pesticides and other chemicals need to be stored away from children and pets.

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13. Tool Cleaning and Sharpening - Routine maintenance begins by removing excess soil from tools with a wire brush and/or by washing.  If rust is present, remove with sandpaper or steel wool or an electric drill with a wire brush or sanding attachment.  Be sure to wear protective eyewear. For winter storage, apply a light coating of oil such as WD-40.  Store tools in a clean, dry place. Tools with wooden parts should not be stored with the wood in contact with soil or concrete. Also sand wooden handles to repair or help prevent cracking and splinters; then treat with linseed oil.

Sharpen tool blades. Tools like shovels are made of hard steel and require a file to sharpen. Hand cutting tools such as pruners, loppers and hedge clippers area made of soft steel and can be sharpened with a file or hand stone. When sharpening, push the sharpening tool the length of the blade and away from the blade. Know how to sharpen the type of pruning tool you have. Sharpening tools correctly takes some experience. If new to this task, or for a refresher, check out this on-line fact sheet from Oregon State Extension on sharpening tools. 

Sharpening Garden Tools, Oregon State University
Cleaning Garden Tools, Nebraska Extension's Backyard Farmer

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