Hort Update for December 26, 2018

Hort Update for December 26, 2018, Nebraska Extension, http://communityenvironment.unl.edu/update12262018
Garden retailers should incorporate Pantone's Color of the Year, Living Coral, in plants, like this coral zinnia, and accessories next year.
Serious ConcernsMajor Symptom:
1. Turf & landscape fertilization

Don't fertilize again until spring to prevent pollution of creeks, streams, lakes & ponds

2. Winter desiccation Winter watering and antidesiccants may be needed to protect valuable evergreens
Timely TopicsMajor points:
3.Weed control in buffalograss Spot treating perennial broadleaf weeds with nonselective herbicide products can still be done if weather permits.
4. Care of late fall or winter laid sod Preventing desiccation of sod critical to survival
5. Ice melt products Select products least likely to damage landscape plants and concrete
6. Pruning and winter protection of grandiflora & floribunda roses Protection should now be in place; with most roses wait until mid to late April to prune
7. Marketing tip Take pictures now of plants with winter interest and use the photos to market plants during spring and fall
8. Pantone "Color of the Year" Make plans to incorporate the 2019 color in displays of plants & accessories


1. Turf & landscape fertilizationDON't fertilize again until spring to prevent pollution of creeks, streams, lakes & ponds

No fertilizer should be applied during the dormant season to lawns, trees, or shrub borders. Plants are not growing and not taking up nutrients. Nitrogen is a very mobile nutrient. It will not stay in place to be available to plants next spring; but it can leach out of the soil profile or runoff to contaminate surface water. Hold off on fertilization until soils begin to warm next spring and roots are actively taking up nutrients. 

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2. Winter desiccationWinter watering and antidesiccants may be needed to protect valuable evergreens

Broadleaf and needle evergreens are at an increased risk of winter desiccation (drying) since they retain foliage year round. Evergreens planted in the last few years and those growing on south facing slopes or near the south sides of homes are most at risk. Adequate summer and fall moisture is most important to preventing winter desiccation that can lead to spring browning or plant death of evergreens.

Winter watering may not be needed due to our adequate rainfall this past season. However, if an absence of snow cover and warm, sunny or windy weather continues, watering can be beneficial. The priority for watering is young plants first - those planted in the last year and especially those planted this past fall; then evergreens, particularly those growing in exposed locations and near the south sides of buildings.

When watering, the soil should not be frozen and air temperatures need to be above 40 degrees F. Irrigation should take place early enough in the day for moisture to soak into 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. If conditions remain warm and dry through winter and into spring, it will be critical to begin irrigation as soon as soils thaw this spring. 

Antidesiccants, also known as anti-transpirants, help plants endure stressful periods by reducing transpirational water loss from foliage. The most common types of antidesiccants are an emulsion of wax, latex, or plastic that forms a thin film on foliage to minimize water loss from plants. We recommend their use on evergreen conifers or broadleaf evergreens in winter, particularly on plants with a history of winter desiccation injury or plants susceptible to winter drying like arborvitae, holly and Mahonia. Select the right product for the plant species as there are toxicity issues. Read and follow label directions.

Apply the product once every six weeks, beginning after plants have completely hardened off in late November. Continue through mid to late February. Avoid covering plants so heavily 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.  

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3. Weed control in buffalograssSpot treating perennial broadleaf weeds with nonselective herbicide products can still be done if weather permits

Glyphosate (i.e. Roundup) is used as a nonselective weed control when buffalograss is dormant, typically from November into March. The key is buffalograss must be fully dormant, to prevent damaging the turfgrass. Perennial broadleaf weeds, like dandelions, must still have green foliage for the application to be effective. 

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4. Care of late fall or winter laid sodPreventing desiccation of sod critical to survival

Early spring and fall are ideal times to lay sod, but winter windows can open up. Sodding in winter can be done as long as winter irrigation is available to minimize winter desiccation on exposed sites. For winter sodding, soil preparation is just as important as for other times of the year and the soil must be moist when sod is laid. Watering after installation is a priority, even in winter. The goal in winter is to keep the crowns moist to prevent winter desiccation and sod death. 

Establishing Lawns From Sod, Nebraska Extension Turf iNfo

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5. Ice melt productsselect products least likely to damage landscape plants and concrete

De-icing agents are sometimes needed for safety but can be harmful to plants. Common deicing compounds are listed below in order of potential plant damage, with the most damaging first. These may be used alone or blended together to improve performance or reduce damage to concrete or landscapes.

  • Sodium chloride is the least expensive product and commonly used on roadways. It has a high burn potential for landscape plants.
  • Urea can harm landscape plants and cause runoff pollution in ponds and waterways.
  • Potassium chloride, also known as muriate of potash, is less damaging than sodium chloride.
  • Calcium chloride is the most effective deicing product at low temperatures, working down to ­‐25°F. It will not damage vegetation if used as directed.
  • Magnesium chloride is sprayed on roadways before a snowstorm to prevent ice bonds from forming, making ice and snow removal easier. It causes very little damage to concrete or metal. It's also gentle on landscape plants and pet safe if used as directed.
  • Acetates can be found in three forms - ­calcium magnesium acetate (CMA), sodium acetate and potassium acetate. CMA is a salt-­‐free product and is the safest product for use around pets and landscape plants. CMA is made from dolomitic limestone and acetic acid (the principal component of vinegar). Studies have shown the material has little impact on plants. It also has a very low level of damage to concrete or metal.

Also keep on hand products that improve your footing on slick surfaces, like sand, sawdust, or cat litter. They can be used instead of traditional deicing products, or blended with them to improve traction and limit deicer use.

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6. Pruning and winter protection of grandiflora & floribunda rosesProtection should now be in place; With most roses, wait until mid to late April to prune

Hybrid tea, grandiflora, floribunda and some cultivars of miniature roses need winter protection. These plants may need pruning to allow them to fit beneath a winter protection method, such as a rose cone, and to remove very tall laterals that may be damaged by winter winds. The majority of pruning should be done in April just before or as new growth begins.

Most roses are protected by covering them. The key is to wait until the plant is hardened off and temperatures are cold. Do not put rose protection in place until soil has frozen or night temperatures are consistently dropping into the 20s at night. Mound 8 inches of soil around the base of roses after soil temperatures have cooled in late fall to protect the plant crown. Use a well-drained soil for this rather than one high in clay. After mounding, moisten the soil mound. After the soil is frozen, apply coarse mulch. A good mulching method is to encircle the rose with a chicken wire cage staked to hold it in place, then fill the cage with coarse leaves. For best growth, wait until April to prune winter killed wood.

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7. Marketing tipTake pictures now of plants with winter interest and use the photos to market plants during spring and fall

There are many plants with winter interest. Promote this benefit to your customers with photos taken during winter to help sell ornamental grasses, trees and shrubs for the right locations. Examples of shrubs with winter interest include coralberry, Aronia berry, Meserve hybrid holly, snowberry, Rugosa rose, and Sumac. Ornamental grasses have long been known for their winter interest; and a number of perennials have evergreen foliage. Take photos now to share with your customers later.

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8. Pantone Color of the Yearmake plans to incorporate the 2019 color in plant & Accessory displays

Living Coral is the 2019 Color of the Year. When shopping this spring, many customers will be looking for Living Coral and colors to accent it. Keep this in mind when planning displays and ordering bedding plants.

Pantone Color of the Year - Living Coral

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Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Nebraska Extension is implied. Use of commercial and trade names does not imply approval or constitute endorsement by Nebraska Extension. Nor does it imply discrimination against other similar products.