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Hort Update for January 23, 2018

Allium 'Millenium', Nebraska Extension Hort Update for January 23, 2018,
LawnsMajor Symptom:
1. Voles May cause surface feeding tunnels in turf beneath snow cover
2. Salt melt products Select products known to cause less damage to plants
Trees & ShrubsMajor Symptom:
3. Wildlife damage Not too late to protect trees and shrubs from rabbits & voles
4. 2017 ReTree list Good trees to plant in Nebraska 
5. 2018 Great Plants for the Great Plains Recommended tree, evergreen, shrub
6. Dormant season shrub pruning Renovation and thinning
7. Optimum time to prune has changed International Society of Arboriculture (ISA) pruning guidelines updated
8. Snow/ice loads Allow ice to melt naturally or gently brush off accumulated snow
Landscape OrnamentalsMajor Symptom:
9. Perennial Plant of the Year Allium "Millenium'
10. 2018 Great Plants for the Great Plains Recommended perennial and grass
11. All-America Selection winners National award winners for 2018
Fruits & VegetablesMajor Symptom:
12. Wait to prune fruit trees Best done from late February through March
13. Fruit Tree Cultivars for Nebraska New NebGuide available with fruit tree cultivar recommendations
14. Prepare pest control spray plans for 2018 Fruit and vegetable spray schedules for homeowners & commercial growers
15. Control fireblight and peach leaf curl during dormancy Copper fungicide applications made during the dormant season provides good control
MiscellaneousMajor Symptom:
16. Don't transport firewood Buy firewood locally

1. VolesMay cause surface feeding tunnels in turf beneath snow cover

Voles will feed on turfgrass beneath snow cover. Vole damage to lawns will repair itself during spring growth and does not cause economic damage. Voles are small, mouse-like rodents that exist throughout Nebraska. Their short, one inch, tails, stocky build and small eyes distinguish them from true mice. Prairie and meadow voles scar lawns by constructing surface runways (one to two inches wide) and clipping grass very close to the crowns or roots. Runways are most visible after snow melts. Small holes lead to underground runways or nesting areas. If populations are high, voles can be trapped to reduce numbers. 

Controlling Vole Damage, Nebraska Extension


2. Salt melt productsSelect products known to cause less damage to plants

Salt melt products One way to protect lawns and landscape plants is to use products with lower potential for damage such as a salt-free melting agent called calcium magnesium acetate (CMA). CMA is made from dolomitic limestone and acetic acid (the principal component of vinegar). Studies have shown the material has little impact on plants. Also consider products that improve your footing on slick surfaces, like sand, sawdust, or kitty litter. These can be used in place of traditional deicing products, or blended with them to improve traction and limit deicer use. The NebGuide linked to below, lists different winter de-icing agents and their safety with plants. 

Winter De-icing Agents for Homeowners, Nebraska Extension
Salt Damage in Landscape Plants, Purdue Extension


3. Wildlife damageNot too late to protect trees and shrubs from rabbits & voles

Check for wildlife damage on young trees and shrubs. It is not too late to protect plants from gnawing by rabbits or voles which can girdle and kill trees. In most home landscapes, the principle culprits are rabbits and voles, but on farms and acreages whitetail deer are also a problem. To prevent damage, much of which can occur in late winter, constructing a physical barrier around plants is the most effective control. Make a cylinder of hardware cloth, 1/4 inch mesh to prevent both rabbit and vole damage. Encircle each plant and bury the wire 6 inches in the soil to prevent voles from tunneling under it. Make the barrier tall enough to stand at least two feet above the anticipated snowline. PVC pipe or black plastic drain-tile can also be used to protect young trees from deer damage. Cut a section long enough to cover the tree's trunk up to the lowest branch. Slit the pipe down one side and fit around the tree's trunk.

Prevent Wildlife Damage in Your Landscape, Nebraska Extension


4. 2017 ReTree ListGood Tree to plant in Nebraska

The Nebraska Forest Service 2017 ReTree list recommends trees for increasing diversity in community forests and to ensure planting quality trees with fewer problems. Refer to this list when selecting trees to purchase for selling or for planting landscapes. Note: A 2018 list is not planned.


5. 2018 Great Plants for the Great PlainsRecommended tree, evergreen, shrub for 2018

The Nebraska Statewide Arboretum and the Nebraska Nursery and Landscape Association, has identified the 2018 Plants of the Year. This year’s shade tree is American Sycamore (Platanus occidentalis), Pinyon pine (Pinus edulus) and American Hazelnut (Corylus americana).


6. Dormant season shrub pruningRenovation and thinning

During dormancy is when deciduous shrubs are pruned to renovate or thin the plant, typically in late February or March.

Thinning is the removal of the oldest and largest diameter stems. These branches are removed back to the base of the plant or where they attach to another branch. Ideally, about one-third of the largest branches are removed at each pruning. On spring blooming shrubs, thinning can also be done just after blooming to avoid removing flower buds and reducing bloom.

Renovation pruning is used on overgrown or leggy shrubs. The entire shrub is cut back to a height of 4 to 10 inches from the ground. Renovation pruning needs to be done while the plant is dormant. While thinning on a regular basis helps preserve a shrubs natural form, and is preferred over renovation; most multi-stemmed shrubs tolerate renovation pruning.

Pruning Deciduous Shrubs, University of Wisconsin Extension


7. Optimum time to prune has changedInternational Society of Arboriculture (ISA) pruning guidelines updated

It was previously recommended the best time to prune most shade trees was during winter dormancy.  New research shows the optimum time to prune living branches is late spring and early summer because pruning at this time promotes the quickest sealing of pruning wounds, known as CODIT or Compartmentalization of Decay in Trees. Late spring and early summer is when tree cells are most active during the growing season, hence sealing occurs the quickest. 

Winter, or anytime during the dormant season, has commonly been the recommended time to prune shade trees. We know trees can be pruned most anytime without killing them, but there are ideal times to prune and times when pruning is best avoided.

We may not have a choice on timing, such as after a wind or ice storm and broken branches need to be removed for safety; but when we have a choice, aim for the ideal time; especially if you are a do-it-yourselfer pruning smaller branches off a smaller tree. Pruning of large branches in large trees should be left to professionals.


8. Snow/ice loadsallow ice to melt naturally or gently brush off accumulated snow 

Snow and ice loads on trees and shrubs can result in breakage. However, improper removal of ice or snow from a tree or shrub can increase damage, and be a safety hazard. In most cases, it is best to allow snow and ice to melt naturally. If not broken, most evergreens branches will return to their natural form.

Never break ice off trees or shrubs by beating the ice covered branches. If it is safe to do so, snow loads can be gently brushed off of trees with a broom. 


9. Perennial Plant of the Year - Allium 'Millenium'Showcasing perennials with outstanding qualities

'Millenium' forms a compact, upright clump of glossy green, thick and strappy leaves which emit a slight smell of onion when crushed. In late July and August here in Michigan, a profusion of large 2”, bright rosy purple, tightly rounded clusters of flowers appear on strong stems just above the attractive foliage.

Allium 'Millenium', Walters Gardens


10. 2018 Great Plants for the Great Plainsrecommended perennials and ornamental Grass

The Nebraska Statewide Arboretum and the Nebraska Nursery and Landscape Association, has identified the 2018 Plants of the Year. This year’s perennial is Virginia mountain mint (Pycnanthemum virgnianum) and the ornamental grass is Bristleleaf sedge (Carex eburnea). To learn more about the characteristics of each of these plants, check out the link below.

2018 GreatPlants Recommendations for the Great Plains, Nebraska Statewide Arboretum


11. All-America Selections winnersKey elements of a soil test report and what they mean

All-America Selection winners are chosen by a panel of expert judges after evaluation for at least two years in trial gardens across the United States. Varieties that perform best over all of North America become AAS National Winners. Entries that performed particularly well in certain regions are named AAS Regional Winners. The AAS Winners offer gardeners reliable new varieties that have proven their superior garden performance in Trial Grounds across North America, thus, our tagline of “Tested Nationally and Proven Locally®”.

This year's national winners include the following.

  • Canna 'South Pacific Orange'
  • Cuphea 'FloriGlory Diana'
  • Gypsophila 'Gypsy White Improved'
  • Marigold 'Super Hero Spry'
  • Ornamental Pepper 'Onyx Red'
  • Zinnia 'Queeny Lime Orange'
  • Pak Choi 'Asian Delight'
  • Cayenne Pepper 'Red Ember'
  • Habanero Pepper 'Roulette'
  • Hungarian Pepper 'Mexican Sunrise'
  • Cherry Tomato 'Red Racer'
  • Tomato 'Valentine'
  • Sweet Corn 'Sweet American Dream'

AAS National and Regional winners can be viewed in the Backyard Farmer display garden on East Campus. Many AAS winners are used in the Raising Nebraska gardens at Nebraska State Fair Park in Grand Island, NE.


12. Wait to prune fruit trees

Best done from late february through march

Pruning fruit trees is best done from late February through March, before trees begin to break bud. This minimizes the potential for cold injury and trees heal wounds fastest when pruned at this time of year. Start with those trees that have higher levels of winter hardiness, including apple, pear, tart cherry and plum. Save sweet cherry, peach and apricot for last. Prune heavily on neglected trees and vigorous cultivars. The main purpose of fruit tree pruning is to 1) increase sunlight penetration of the tree's canopy, 2) remove less productive wood and 3) shape the crown into a strong efficient structure. Pruning increases fruit size, promotes uniform ripening, increases fruit sugar content and decreases pest problems due to better spray coverage and faster drying of the foliage after rain.

Occasional summer and fall pruning may be needed, but keep it to a minimum to avoid spreading fireblight and creating wounds that can be invaded by other diseases.

Make proper pruning cuts and use sharp pruning tools. Do not use pruning paints or wound dressings on pruning wounds. If a fruit tree sustains storm damage, consider removing the tree if over 50% of the trees branches need to be removed due to breakage. 


13. Fruit Tree Cultivars for Nebraskanew nebguide available with fruit tree cultivar recommendations

Proper fruit cultivar (variety) selection is important for successful and satisfying results from the home gardener’s efforts. Selection should be based on family preferences, available space, and intended use of the fruits. If properly chosen, harvest can be spread over several weeks if cultivars with different periods of maturity are planted.

Fruit Tree Cultivars for Nebraska, Nebraska Extension


14. Prepare pest control spray plans for 2018fruit and vegetable spray schedules for homeowners & commercial growers

Fruits & vegetables are susceptible to a number of disease and insect pests. Often, selection and planting of resistant cultivars will reduce the need for pesticides. When needed, timing of pesticide applications is critical to effectively controlling targeted pests. For recommended spray schedules see the following publication.


Commercial Growers:

  • 2018 Midwest Fruit Pest Management Guide was developed by the Midwest Fruit Workers Group. This publication combines two longtime guides that have become familiar to countless growers: the annual Midwest Small Fruit and Grape Spray Guide and the annual Midwest Tree Fruit Spray Guide. Members of the Midwest Fruit Workers Group decided to combine these publications in order to address the needs of many producers who grow many different crops. It is our hope that this new combined publication will make it easier for producers to find the accurate information they need for managing pests in fruit crops. It is a joint publication of University of Arkansas, University of Illinois, Purdue Extension, Iowa State University, K-State Research and Extension, University of Kentucky, University of Minnesota, University of Missouri, Missouri State University, Nebraska Extension, Ohio State University, Oklahoma State University, West Virginia University and University of Wisconsin.
  • 2018 Midwest Vegetable Production Guide for Commercial Growers - This annual guide is a summary of currently suggested vegetable varieties, seeding rates, fertilizer rates, weed control, insect control, and disease control measures for commercial growers.


15. Plan for dormant spray applicationsuccess relies on early detection and effective controls

Application of copper fungicide is an effective way to control fireblight and peach leaf curl when applied to dormant fruit trees during late winter. Bordeaux mixture, a combination of copper sulfate and lime, or fixed copper fungicides, such as tribasic copper sulfate, copper oxychloride sulfate and cupric hydroxide, can be used. Bordeaux mixture has the advantage of adhering to plants better during rainy weather, but it does stain surfaces and can cause plant damage if applied after plants have broken dormancy.

Fireblight, University of Minnesota Extension
Peach Leaf Curl, Ohio State University Extension


16. Don't transport firewoodbuy firewood locally

The Nebraska Department of Agriculture strongly advises that in general, no firewood be brought into Nebraska from other states to prevent the spread of pests.

  • Many states in the Great Plains region near Nebraska have areas under quarantine for pests such as emerald ash borer, gypsy moth, and thousand cankers disease, and it is illegal to move any regulated items (most firewood is considered a regulated item) from quarantined zones out of those states and into Nebraska.
  • Nebraska also has five counties under quarantine for emerald ash borer—Cass, Dodge, Douglas, Sarpy and Washington—because of the discovery of the EAB in Cass and Douglas counties in 2016. It is against the law to move firewood from inside those counties into other parts of the state.