University of Kentucky HortMemo

HortMemo - A University of Kentucky Cooperative Extension Service Newsletter for the Kentucky Nursery/Landscape Industry
Current 2016 HortMemo below

by Winston C. Dunwell, Professor - Nursery Crops Development Center

UK Department of Horticulture

To subscribe send an e-mail to cforsyth@uky.edu or call Christi, 270.365.7541 x 221.

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June 7, 2016



Zenaida Viloria, Extension Associate for Nursery Crops at the UKREC is continuing to trap ambrosia and camphor beetles.  She will let us know when there are no more captures and look for her report at the end of the season.


Great Upcoming Events!!!


The Academy of Crop Production: The Place You Go…. to Learn To Grow! (Pest and ISA CEUS) June 12 – 15, 2016. The Indigo Hotel, Downtown Athens, Georgia. Contact: Matthew Chappell at Hortprod@uga.edu or call 770-580-9715 url, https://estore.uga.edu/C27063_ustores/web/product_detail.jsp?PRODUCTID=4788
The Academy of Crop Production is a Southern-centric four-day conference dedicated to sharing information on ADVANCED ornamental crop production and business management techniques for ornamental producers. Hosted by the University of Georgia and the Georgia Green Industry Association, at the beautiful Hotel Indigo (Athens, GA).
We will offer 5-8 credit hours of pesticide CEUs and 3-5 hours of ISA regional credits (depending upon state/ISA region) for Georgia, Alabama, Florida, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee and Virginia.


The UKREC Horticulture Field Day will be Thursday, June 23, 2016, 1205 Hopkinsville Street, Princeton, KY.  http://www2.ca.uky.edu/HLA/Dunwell/UKRECHortField2016.pdf





8:45-9:00 am


UKREC Ornamentals

9:00-10:30 am

Plant Evaluations & Overview
Blueberries in Containers
Controlled Release Fertilization in White Oak Seedlings
Everris® Blue Max™ Coated
Aluminum Sulfate in Hydrangeas
Annual Bedding Plant Trial

Dr. Winston Dunwell
Dr. Dewayne Ingram
Carey Grable
Dr. Zenaida Viloria
Ginny Travis
June Johnston

Note : there will be two tours of ornamentals, the first one will  be at 9:00-10:30 am and the second 10:30-12 pm





8:45-9:00 am


UKREC Orchard

9:00-12:00 pm

Blueberry Production in Containers
Blackberry Cultivars, Production, and
      Pest Management
Cherry Rootstock & Training Trial
Peach Rootstock & Cultivars, Production and Pest Management
Apple Rootstocks & Cultivars, Production and Pest Management
Grape Cultivars, Production and Pest Management

Dr. John Strang
Dr. Ric Bessin
Dwight Wolfe
Christopher Smigell
Daniel Becker

Note: The tour will visit the fruit trials. Each panelist will contribute information relative to that fruit. There will be only one tour of fruit crops. 


Win Dunwell is hosting his colleagues from the Southeast Plant Evaluation Group and they will be giving a public program June 29, 2016 at Yew Dell Gardens.

Southern Garden All-Stars: Developing and testing the best new plants for southern gardens
Program Description: This day of lectures and tours features some of the best plant experts from across the Southeast. Representing land grant universities and other plant institutions, the presenters will offer insights into some of the most exciting new-plant work going on across the region.  Engaging morning and early afternoon lectures will be followed by a walk of Yew Dell’s plant collections with commentary by the speakers. Cost: $35/$45 (Yew Dell members/nonmembers) Reservations made by 6/27 will include a box lunch.
To register call 502.241.4788 or go to www.yewdellgardens.org/classes-and-events.html
Program Schedule:
8:30-9am         Registration and check in
9-9:15am         Welcome and Introductions
                              Paul Cappiello, Yew Dell Botanical Gardens, Executive Director
9:15-9:40         All-America Selections Winners: 84 Years of Outstanding Garden Performers
      Gene Blythe, Mississippi State University, Associate Research Professor; Ornamentals
9:40-10:05       Something to Bark About
                              Alex X. Niemiera. VA Tech, Extension Horticulturist
10:05-10:30     Coffee Break
10:35-11:00     Advances in Magnolia Breeding: New Magnolias from the Arctic to the Equator
                              Gary Knox, University of Florida, Professor of Environmental Horticulture
11:00-11:25     Plant breeding for function - how to screen your children to be tough
                              Matthew Chappell, University of Georgia, Assistant Professor of Horticulture

11:25-11:50     Highlights from the LSU AgCenter Trial Gardens in Hammond, LA
      Allen D. Owings, Louisiana State University, Professor and Research Coordinator
11:50-12:45     Lunch
12:45-1:10       Kentucky “Local Plants” Project
      Win Dunwell, University of Kentucky, Extension Horticulture Specialist, Nursery Crops
1:10-1:35         Osmanthus for the Mid-South
                              Lisa Alexander, US National Arboretum, Research Geneticist
1:35-3:00         Tour Yew Dell’s plant collections with executive director Paul Cappiello and program speakers


Hydrangeas A to Z workshops: July 21, 2016 in McMinnville, Tenn., August 2, 2016, Virginia Beach, Va., and August 4, 2016, Smithfield, N.C. Contact: https://secure.touchnet.com/C21610_ustores/web/product_detail.jsp?PRODUCTID=791 .The events have been co-organized by North Carolina State University, University of Tennessee, and Virginia Cooperative Extension and will feature the following speakers: Matthew Chappell, University of Georgia; Amy Fulcher, University of Tennessee; Anthony LeBude, North Carolina State University; Jim Owen, Virginia Tech; Alan Windham, University of Tennesee
Topics: Potting Substrate and Fertilizers, Bluing Flowers; Controlling Growth and Enhancing Flowering with Pruning and PGRs; Propagation and Breeding Hydrangeas, New Releases; Disease Management. 
Win says he will be attending the Tennessee workshop.  For those interested in Hydrangeas the Horticulture Group at the UKREC, Princeton has worked with researchers on UK campus to evaluate Hydrangea species and cultivars for over 20 years and we now have trials of the new Hydrangea macrocarpa re-flowering types that have looked promising with the research by Carey Grable and Dewayne Ingram on fertilizer influences on color in container production.


March 21, 2016



I have been invited by the Friends of the UK Arboretum to speak about a topic near and dear to my heart – Kentucky native plants this Thursday, March 24, 2016 at 7 p.m. in UK’s Gluck Auditorium.  The topic title is Kentucky Native Plants: Selection and Care - A discussion of selected Kentucky native plants useful in Kentucky landscapes.  The presentation will include observations, propagation, growing and care of these wonderful plants.


Joe Collins, President National Plant Board, Office of the State Entomologist, Dept. of Entomology, Lexington KY http://nationalplantboard.org and http://www.uky.edu/Ag/NurseryInspection shared with the UK Nursery Crops Group that there is a “new plant certification system designed to help reduce the spread of pests. It is called SANC – Systems Approach to Nursery Certification and it is strictly voluntary. SANC is an audit based system of certification. The first step that a nursery must do is to complete a risk assessment which identifies critical control points (CCP) and uses BMPs to address those situations. 
----there are a lot of parts to it---”. Joe recommends taking a look at the SANC website for a description of what it is all about http://sanc.nationalplantboard.org. This is a Q&A which might help as well: http://sanc.nationalplantboard.org/wp-content/uploads/2013/08/SANC-QA1.pdf


Southern IPM sent out the link to Here’s How to Inspect Your Trees for Emerald Ash Borer March 7, 2016 by Entomology Today included in the article is a video on assessing the possibility of EAB infestation.
for a scientific outlook download the Arboriculture and Urban Forestry 41(2): March 2015 article


Chionanthus virginicus – Fringe Tree has been found infected with Emerald Ash Borer in Ohio.  Below are two trees from the Spring Grove Cemetery where the one on the left is showing symptoms of injury; stunted, thin, yellowing leaves and the hole of the exiting insects in trunks. The one on the right is a cut back following infection showing the extreme vigor of a massive root system supporting new growth. Don Cipollini wrote: “I report here evidence that emerald ash borer can attack and complete development in white fringetree, Chionanthus virginicus L., a species native to the southeastern United States that is also planted ornamentally.” https://jee.oxfordjournals.org/content/108/1/370.full First published January 15, 2015, Darn a beautiful native in jeopardy.  Fringe tree is difficult to propagate and we have been testing different sequences of hot and cold to try to speed up the seed germination process. Considering the potential lack of market for fringe tree now that EAB attack has been confirmed we will stick with Bill Hendricks, Klyn Nursery, method of setting flats of seeds in media (sand, perlite) in the corner of overwintering houses and waiting the 2 – 3 years for the seed to germinate.


There is a new program, Seed Your Future, by Longwood Gardens and the American Society for Horticultural Science. From the business plan the Goals and anticipated outcomes are: Goals; 1) Change the perception of horticulture by increasing public awareness of the positive and diverse attributes of the profession and 2) Increase capacity in horticulture through a perception shift that drives talented young people to view horticulture as a vital, viable, and vibrant career path. Anticipated Outcomes; 1) Improve the public’s perception of horticulture and horticultural careers. 2) Engage and excite youth about horticulture in their lives and school curriculum and promote participation in horticultural organizations such as the National Junior Horticultural Association, Junior Master Gardener®, 4-H, and FFA. 3) Increase number of high school students in horticulture and plant sciences programs. 4) Increase number of horticulture students in 2-year and 4-year college and university programs. 5) Increase number of well-trained, well-educated horticulture employees. For more information go to the website http://www.seedyourfuture.org


Nicole’s information on fire blight applies to ornamental crabapples, pears, Photinia and other Rosaceae family plants is distributed through Dr. John Strang’s Kentucky Fruit Facts electronic mailing list. To subscribe, send an email message In order to get those you have to sign up for Dr. John Strang’s Apple Alert Listserve by e-mailing John at jstrang@uky.edu and he will add you to the list.


Fire Blight Alert and Risk Map Overview By Nicole Ward Gauthier
(To be distributed weekly through orchard bloom)
Apple trees are approaching bloom and many pear are in full bloom, especially in southwestern Kentucky. Infection by the fire blight bacterium occurs during bloom, thus, protectant antibiotics should be applied when risk is high. 
Risk for infection can be assessed using the Fire Blight Disease Prediction Model. Growers can assess local risk by selecting their county and orchard history. This model incorporates the previous 4 days of weather data plus adds a 7-day forecast for estimating leaf wetness and temperature (thereby estimating risk for bacterial growth and infection). There are 66 Mesonet weather stations throughout Kentucky, thus, weather information for the model is based on data from the closest weather station. For a mobile (phone or tablet) friendly version of this site, visit http://weather.uky.edu/dim.html.
Remember that apple and pear trees must be in bloom for predictions to be accurate. The map overview below indicates fire blight risk as of March 21, 2016.  According to the current assessment, risk is low due to the cool dry weather.  A rain event, however, can increase that risk.  Growers are encouraged to check the model regularly for the most accurate analyses and county-specific forecasts.
Information regarding prevention and management of fire blight can be found in:
Commercial Fruit Pest Management Guide (ID-232)
Backyard Apple Disease Management Using Cultural Practices (PPFS-FR-T-21)
Fire blight (PPFS-FR-T-12)
Fire blight of Apple (Video)



March 2, 2016



The new Extension Associate for Nursery Crops is here. Dr. Zenaida Viloria will be stationed at the UKREC, Princeton, KY and will be serving the Kentucky nursery industry in cooperation with Carey Grable, Extension Associate for Nursery Crops housed in Lexington. Her office phone number is 270.365.7541 x 279.  Her e-mail is zenaida.viloria@uky.edu Her educational training was a Ph. D. in Horticultural Sciences, 2003, University of Florida, Gainesville, Florida and an Agricultural Engineering Degree, 1984, La Universidad del Zulia, Maracaibo, Venezuela. In addition to her past research work on fruit Zenaida has worked with Dr. Thomas Ranney, NCSU Ornamental Plant Breeder, Mountain Horticultural Crops Research & Extension Center, Mills River, NC.  We are already impressed by her work ethic, attention to detail and study to learn about nursery production in Kentucky. If you need a consultation please give her a call.


AnemoneHonorineJobertIn the subject line you may have read “To subscribe to the KYNURSERIES-L Listserve, email joshua.knight@uky.edu and put KYNURSERIES-L subscribe in the subject.”  Josh Knight administrates the nursery listserve that sends out an informative newsletter on a regular basis.  It contains a great deal more information than HortMemo’s brief notes/notices. It is prepared by Josh and members of the UK Nursery/Landscape program. For a look a previous e-mail postings go to the UK Nursery Crop Research and Extension webpage  http://nursery-crop-extension.ca.uky.edu and click on the LISTSERVE drop down and you will be taken to the page with KYNURSERIES-L subscribe directions and archives.


Anemone x hybrida 'Honorine Jobert' is the Perennial Plant Association 2016 plant of the year. 'Honorine Jobert' Anemone was found in Jobert Gardens in Verdun, France in 1858. It fits into the “tried and true” category of a perennial plant for Kentucky gardens that blooms in late summer or fall. The picture (yes scanned from a slide) was taken at Bernheim Arboretum years ago.

Most recent bloom at the UKREC is Cornus mas ‘Spring Glow’ and Prunus ‘First Lady’. For images; Cornus mas Spring Glow http://tinyurl.com/j5duuvd and http://tinyurl.com/hwhahb5  First Lady  http://tinyurl.com/hdjzdzb or http://www.usna.usda.gov/Newintro/Prunus_FirstLady_LR.pdf


Meetings of Note:

A Tree Workshop (4.5 ISA arborist CEUs) with information for green industry professionals, developers, public landscape managers, homeowners, neighborhood tree program enthusiasts will be held April 6, 2016 from 0930-1600 ET at Yew Dell Gardens, 6220 Old LaGrange Road, Crestwood, KY. There is a fee for registering. For more information contact: Yew Dell Gardens, 502-241-4788 or http://www.yewdellgardens.org to register go to http://www.yewdellgardens/clases-and-events.html


The California Spring Trials are a week of travels to different plant company sites to see the latest and the greatest plants, plant production research and merchandising by visiting plant trials sites from southern California to northern California. April 9-14, 2016.  Many sites and plant companies are involved for a complete list see: http://www.americanhort.org/springtrials


Mid-South Prairie Symposium emphasizing the ecology, conservation, restoration, and management of prairies, barrens, savannas, and woodlands of the Interior Plateau Ecoregion will be May 25-27, 2016. The event will be at the Sundquist Science Complex, Austin Peay State University, 8th St, Clarksville, Tennessee 37040. Contact: Dwayne Estes; e-mail, destes@brit.org or see the web page, http://www.apsu.edu/herbarium/purpose-symposium

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February 1, 2016



I will be talking about “Great Trees & Shrubs for 2016 NKY Landscapes” (and how we grow them) at the Commercial Arborist, Landscaper & Nursery Worker Seminar.  February 16, 2016.  Boone County Cooperative Extension Enrichment Center, 1955 Burlington Pike, Burlington, KY 41005.  Contact: Mike Klahr, Boone County Extension, 859-586-6101, or enroll online https://www.boone.ca.uky.edu I am first up at 8:30 am but many great presenters are on the program and Arborist and Pesticide CEUs can be earned from attendance.


Dr. Don Hershman sent in an image of redbud bark falling off. Eastern redbud tends to shed bark on older trees revealing an orangish-brown inner bark. Recommendations: There is nothing wrong with the tree as long as the shedding bark simply reveals underlying bark rather than bare wood.


UKREC Horticulture Open House will be Thursday, June 23, 2016, 9:00 am to 12:00 noon at the University of Kentucky Research and Education Center, 1205 Hopkinsville St, Princeton, KY 42445. Presentations on fruit and vegetable production and ornamental tours of plant collections and nursery research will be the program.  Contact: Win Dunwell, 270.261.9467, wdunwell@uky.edu; url, https://nursery-crop-extension.ca.uky.edu/UKRECHortToursEducation


Chilling hours accumulation from November 1st to February 1st at 41°F are 359 for Paducah, 329 for Lexington, & 447 for Covington.  I use the UKAg Weather Center <http://weather.uky.edu> Chilling Hour Model to get the numbers http://weather.uky.edu/php/chillhour_www.html


Bill Fountain wrote an article related to the outcome of the winter of 2014-2015 that contains information while written in the spring of 2015 directly related to last year’s winter some of his discussion is pertinent to this winter and may give us some idea of what to expect.  http://www2.ca.uky.edu/HLA/Dunwell/WinterInjury_BillFountain_2015.pdf


SNA DATE and LOCATION CHANGE: SNA 2016 will be August 30 - September 1, 2016 at The Classic Center, Athens, GA 30601. For more information contact Karen Summers, SNA Executive VP, 678.809.9992; e-mail, ksummers@sna.org ; url, http://www.sna.org


Dr. Matthew Chappell, UGA Professor Nursery Crops, put out a call to his colleagues for nursery landscape resources and I cut and pasted from the replies (see below):


Cheryl Wilen, Ph.D. Area IPM Advisor, IPM Advisor Extension Coordinator, Endemic and Invasive Pests and Diseases Strategic Initiative Leader, UC Statewide IPM Program & UCCE, San Diego, CA 92123 replied following comments on Joe Neal's publication mentioned a database that was recently completed.  While not specifically for ornamentals, it does allow for searching. http://herbicidesymptoms.ipm.ucanr.edu/index.cfm?src=ipm1


We commented on going to Joe Neal’s website to find publications on Nursery Landscape Weed control in the last HortMemo but to be more specific Joe Neal’s NCSU Nursery/Landscape Weed Program completed an on-line fact sheet series on herbicide injury symptoms. 
Also available on Joe’s web site are fact sheets on PRE herbicides labeled for nursery and landscape uses.
and, updated tables of all herbicide ai's labeled for woody and herbaceous ornamental crops, Herbicide efficacy rankings. http://www4.ncsu.edu/~jcneal/
Joe reports they are still working to include more images, and a searchable diagnostic "front page"  for the herbicide injury symptoms series, the fact sheets are completed and may be of interest in the coming season... especially if there are glyphosate resistant crops next door..... 


Whitney Yeary, Amy Fulcher and Brian Lieb wrote Nursery Irrigation: A Guide for Reducing Risk and Improving Production. Amy reports that a strong part of the publication is the success stories.  <http://plantsciences.utk.edu/pdf/fulcher_irrigation_manual.pdf>

Quinn Cypher and Amy Fulcher recently published an online publication series covering alternatives to petroleum-based plastic pots including plantable and biodegradable containers. It is titled Beyond Plastic Pots and the publication numbers are W337A-D in case that helps.  https://extension.tennessee.edu/publications/pages/default.aspx?k=W337&cs=This%20Site&u=https%3A%2F%2Fextension.tennessee.edu%2Fpublications


Dr. Amy Fulcher continues working to get IPMPro updated to version 2 with a new look and additional information and functions.  We will keep you up on the status as it gets closer to completion.

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January 5, 2016



See you at KNLA’s Spring Training & Showplace, January 27-28, 2016. Ramada Plaza Louisville Hotel and Conference Center http://knla.org/event/knlas-spring-training-showplace

The Kentucky Nursery and Landscape Association created a KNLA Wholesale Nursery Location Map of nurseries that participated. It can be found at http://knla.org/wholesale-nursery-location-map or you can pick up a printed copy at the KNLA Spring Training & Showplace.


We have had numerous inquiries about the effect of the warm temperatures followed by the dramatic drop in temperature on landscape, nursery and edible plants. At this time it is very hard to tell. Last year in December we had some forsythia in bloom, a few scattered azalea blooms, and typical winter yellow blooms of Mahonia and bloom on witchhazel pretty much as we do now. We have not observed the bark cracking on small Crapemyrtles and other marginally sensitive plants nor any obvious twig death typical of temperature shifts. There would not seem to be cause for worry. But truth be told, we just don’t know. Last year we were pretty sure the -13°F had to have killed the peach buds but some twigs brought into the warm lab produced flowers and the UK Princeton orchard had one of the best crops ever. The chilling hours at a temperature threshold (Less than or equal to) of 41°F in Paducah are 409, Lexington 384, Covington 493 to December 31, 2015. Chilling hours necessary for bloom of cherries is about 800 but persimmon is 200-400 and given warm temperatures could lose hardiness or bloom any moment. There is some variability in fruit trees in our edible landscapes, e.g. highbush blueberry requires 900-1000 hours while southern highbush only need 150-500 depending on variety; peaches vary greatly from 400-1050. We will just have to wait and see. Chilling while required is not the only factor that impacts when a plant blooms. Growing Degree Hour (heat) requirements also have to be met in order to have bud and flower development.

Mt Cuba Center under the leadership of researcher George Coombs has completed a Research Report on their Coreopsis trials for the mid-Atlantic region. The trials were on clay-based soils and may have some application to Kentucky. The summary is “Mt. Cuba Center 's coreopsis trial evaluated the performance of both annual and perennial tickseed. The best performing perennial species (those marketed as hardy to Zone 6) were C. palustris 'Summer Sunshine', C. tripteris 'Flower Tower ', C. tripteris 'Gold Standard', C. verticillata 'Zagreb', C. integrifolia 'Last Dance', C. 'Gilded Lace', and C. verticillata 'Golden Gain'. Among the cultivars sold as annuals, 'Salsa', 'Jive', 'Golden Dream', 'RP #1' (Little Penny), and 'Pineapple Pie' stood above the rest for their superior garden performance. The report (along with others on the right margin) can be found at http://www.mtcubacenter.org/horticultural-research/trial-garden-research/annual-coreopsis-report-2014


Joe Neal has listed numerous weed control and herbicide publications on his home page under the headings Resources and Weed Control Fact sheets. http://www4.ncsu.edu/~jcneal for those interested in nursery/landscape weed control he is developing an herbicide damage image resource that will be available in the future.


While we are talking about Nursery Crops Pest Management a group under the leadership of Joe Neal is putting together a Southern Nursery Crops Pest Management publication that will cover the whole area with annually updated chemical recommendations. In the meantime the Virginia Tech publication by Chuan Hong, Peter Shultz, and Jeffrey Derr covers nursery crop disease, insect and weed pests and can be found as a PDF at https://pubs.ext.vt.edu/456/456-017/Section-5_Nursery_Crops-1.pdf


Black knot is a serious disease of Ornamental Prunus species. A revised Black Knot publication PPES-FR-T-04 by Nicole Ward Gauthier and Dennis Morgeson has been posted to http://www2.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/PPFS-FR-T-4.pdf

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