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Hort Update for Jan. 23, 2017

Major Symptom:
1. Pesticide certification for training dates and certification information
2. Winter injury Caused by crown hydration, desiccation or low temperatures
3. Dormant seeding Could be done if seedbed preparation took place last fall
Trees & Shrubs  
4. Become a certified arborist
5. Proper pruning techniques Good pruning techniques speed tree wound closure
6. Wildlife damage Protect trunks by encircling with hardware cloth; apply repellants
7. Tree recommendations ReTree Nebraska and Tree of the Year recommendations
Landscape Ornamentals  
8. All-America Selections in Backyard Farmer garden Well-tested garden varieties displayed in the BYF gardens on UNL's East campus
9. Check on mulch Rake it back onto plants or add additional mulch if needed
Fruits & Vegetables  
10. Hops growing in Nebraska Upcoming alternative crop for Nebraska growers
11. ProHort classes In-depth training for commercial horticulture professionals
12. NFS Tree Care Workshops For public works employees, landscape managers, tree board volunteers, arborists, nursery and green industry professionals

1. 2017 Commercial Pesticide Applicator training dates - Any person that applies general use and/or restricted use pesticides for hire to ornamentals and/or turf must be a licensed and certified applicator. Commercial pesticide training and testing takes place in February and March. For information on pesticide training, go to

Training Dates


2. Winter injury to turfgrass is typically due to crown hydration, dessication, or low temperatures.  Snow provides insulation to protect turfgrass from cold temperatures and dessication. Open winters with little snow fall increases the risk of dessication and low temperature injury. Melting snow, rain, and ice all increase the risk of crown hydration injury. For more information on these causes of winter kill of turfgrass, see Michigan State Universities publication Winterkill of Turfgrass.

New seedlings from fall plantings can be at higher risk of low temperature injury.  If planting was done prior to September 15, seedlings should have been established well enough that little damage will occur. If planting was done after September 15, these seedlings are at higher risk of cold temperature and or winter dessication injury.  If injury occurs, reseeding or overseeding of thin areas may be needed this spring.


3. Dormant seeding involves seeding while the ground is not frozen, but cold enough that seed germination will not occur until after soils begin to warm in spring. Other than the time of year of dormant seeding, typically mid-December through Valentine’s Day or Spring Break, the actual process of preparing the area to be seeded is the same as for seeding at other times of the year. If seedbed preparation took place last fall, and soils are not frozen, dormant seeding can take place now. The risk of dormant seeding is warm winter and early spring temperatures may cause seed to germinate and then a subsequent cold period kills the seedlings. When using dormant seeding, monitor seeded areas in mid spring for the need to do additional overseeding.

Establishing Lawns from Seed, Nebraska Extension Turf iNFo


4. Become a Certified Arborist - Certification benefits the profession of Arboriculture in Nebraska by improving the overall quality of tree care provided. The program sets a standard for quality tree work that can be recognized by the public. In addition to participating in various educational meetings, Certified Arborists also enjoy many other benefits. To learn more, go to the Nebraska Arborist Association website or to the International Society of Arboriculture website.


5. Proper pruning cuts not only improves a trees appearance; it helps trees respond best to pruning for wound compartmentalization and to reduce the risk of wound decay. Incorrect pruning cuts are common but can easily be avoided. Incorrect cuts fairly easy to avoid are flush cuts (cutting too close to the trunk or a large branch) and stub cuts (leaving a branch stub). A correct cut is made just outside of the branch collar and branch bark ridge. For a diagram showing this, see the link below. And as always, do not treat pruning wounds with any kind of wound dressing or paints. Science shows these increase the risk of decay in trees by interfering with the trees own response to wounding. Other pruning methods that need to be avoided include topping and lion-tailing or lions-tailed. These not only destroy the aesthetics of a tree, they lead to decay in tree branches and greatly increase the hazard risk of a tree.

March - A Great Time for Tree Pruning, Nebraska Extension
Pruning Cut Types, University of Florida


6. 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 as they do wear off.


7. Tree recommendations - When selecting or recommending trees, think diversity to help avoid monocultures (planting too many of one type of tree). This will help avoid issues such as the loss of American Elm due to Dutch Elm Disease and the upcoming loss of many ash trees due to emerald ash borer. For ideas on good trees to plant, check out the following sources:


8. All-America Selections and BYF Garden - Did you know you can view All-America Selections (AAS) in the Backyard Farmer display garden on UNL’s east campus? AAS National and Regional Winners have been tested for garden performance by a panel of expert judges. 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®”.

Downloadable Excel file of all AAS Winners from 1932 to present.


9. Check on winter mulch - Lack of snow along with windy conditions may have blown mulch off of tender perennials. Check mulched plants in landscapes or gardens to see if mulch needs to be raked back onto plants or additional mulch added. If concerned about a plant that was not mulched, it’s not too late to add mulch. Place a ring of hardware cloth or chicken wire around the plant and fill it with large, coarse leave, wood chips or straw.


Hops Growing in Nebraska, Hort Update for January 23, 2017, Hops growing in Nebraska - If you’ve driven north of Plattsmouth on Highway 75 recently you’ve probably wondered about the 18-foot trellises off on the east side of the road.  Those are hop trellises.  The hop plant (Humulus lupulus) is an herbaceous perennial, usually grown for its strobiles or cones. Hop cones contain different oils, such as lupulin, a yellowish, waxy substance, that provides flavor and aroma to food products like beer.

Hops Growing in Nebraska, Hort Update for January 23, 2017, the growing season, an individual hop plant can weigh 30 to 40 pounds.  So at one thousand plants per acre that trellis has to be strong enough to support 30 to 40 thousand pounds of bines, leaves, and cones.  In 2016 Nebraska had around 24 acres of hops harvested.  There were additional acres not yet in production and there are plans for more acres to be planted in 2017 and 2018.

So why hops in Nebraska and why now?  That has a lot to do with changing purchase habits of Americans – interest is shifting to craft beers over mass-produced beers and more and more folks are making an effort to buy local.  Nebraska has the appropriate climate and day length to produce quality hops and our growing conditions give the product a certain terroir (yes, just like with wine, the soils that produce hops have a huge impact on their character) that intrigues and excites brewers.

So there is demand for Nebraska-grown hops, especially from Nebraska craft breweries.  This was evident at the inaugural Nebraska Grower and Brewer Conference held January 5-6, 2017 on the Nebraska Innovation Campus in Lincoln.  More than 180 attendees came to hear from university specialists and experienced growers and brewers from Nebraska and other states in the Midwest.  There is already buzz about next year’s conference – stay tuned for details.

Are hops for you?  Maybe you own or manage property and are thinking about growing hops.  The first thing to consider is distance from a processor.  Most hops are sold to brewers after they’ve been dried and pelletized, so you need to do your homework in that regard BEFORE you invest.  If you work with a company like Midwest Hop Producers out of Plattsmouth they can share what they know about hop production and pest management, the varieties local brewers prefer, and quality parameters.

Not ready to plant, but you’d like to support the cause?  The University of Nebraska-Lincoln has a hop breeding program.  Dr. Keenan Amundsen is eager to produce a Nebraska hop and he needs our help.  If you have wild hops growing on your property, please let him know so he can come out and collect plant material to potentially use in breeding projects.  During the summer, when you can easily see the cones, is a great time to mark the locations of female hop plants.


11. ProHort classes are 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. Pre-registration required by completing the 2017 ProHort Registration form. Class schedule.


  • Nebraska Extension in Douglas-Sarpy Counties
  • 8015 West Center Road 68124


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


12. Nebraska Forest Service Tree Care Workshops - Develop specifically for public works employees, landscape managers, tree board volunteers, arborists, nursery and green industry professionals and landscape enthusiasts, these workshops cover emerging issues in tree and landscape care.

  • February 29, Knight Museum, Alliance
  • March 1, West Central Research and Extension Center, North Platte
  • March 2, Lower Loup NRD Office, Ord
  • March 3, Harmon Park Activity Center, Kearney
  • March 7, UNL Agricultural Research Development Center, Mead
  • March 21, Lifelong Learning Center, Norfolk

Cost is $45.00 per person, lunch included. Workshops are eligible for commercial arborist CEUs.

For more information, contact Graham Herbst, (402) 444-7875, or Amy Seiler, (308) 633-1173. Or send us an email for more information.

The Tree Care Workshops are a partnership between the Nebraska Forest Service and the Nebraska Statewide Arboretum.