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Horttechnology | 2017

Performance of Landscape Roses Grown with Minimal Input in the North-central, Central, and South-central United States

David C. Zlesak; Randy S. Nelson; Derald A. Harp; Barbara Villarreal; Nick Howell; Jason J. Griffin; Gaye Hammond; Steve George

Landscape roses (Rosa sp.) are popular flowering shrubs. Consumers are less willing or able to maintain landscape beds than in years past and require plants that are not only attractive, but well-adapted to regional climatic conditions, soil types, and disease and pest pressures. Marketing and distribution of rose cultivars occurs on a national level; therefore, it is difficult for U.S. consumers in the U.S. Department of Agriculture (USDA) Plant Hardiness Zones 3 to 5 to identify welladapted, cold-hardy cultivars. Identifying suitable cultivars that have strong genetic resistance to pests and disease and that will tolerate temperature extremes without winter protection in theUSDAPlantHardiness Zones 3 to 5 is of tremendous value to consumers and retailers in northern states. Twenty landscape rose cultivars, primarily developed in north-central North America, were evaluated at five locations in the United States (three in the north-central United States, one in the central United States, and one in the south-central United States) using the lowinput, multiyear Earth-Kind methodology. Six roses had ‡75% plant survival at the end of the study and were in the top 50% of performers for overall mean horticultural rating at each of the three north-central U.S. sites: ‘Lena’, ‘Frontenac’, ‘Ole’, ‘Polar Joy’, ‘Sunrise Sunset’, and ‘Sven’. Five of these six roses met the same criteria at the central United States (exception ‘Lena’) and the south-central United States (exception ‘Polar Joy’) sites. Cultivar, rating time, and their interaction were highly significant, and block effects were not significant for horticultural rating for all single-site analyses of variance. Significant positive correlations were found between sites for flower number, flower diameter, and overall horticultural rating. Significant negative correlations were found between flower number and diameter within each site and also between black spot (Diplocarpon rosae) lesion size from a previous study and overall horticultural rating for three of the five sites. Cane survival ratings were not significantly correlated with overall horticultural rating, suggesting some cultivars can experience severe winter cane dieback, yet recover and perform well. Data from this study benefit multiple stakeholders, including nurseries, landscapers, and consumers, with evidence-based regional cultivar recommendations and breeders desiring to identify regionally adapted parents.


Archive | 2008

Earth-Kind ® Rose Trials - Identifying the World's Strongest, Most Beautiful Landscape Roses

Derald A. Harp; David C. Zlesak; Gaye Hammond; Steve George; Wayne A. Mackay


Texas Journal of Agriculture and Natural Resources | 2016

Compost Type Affects Bermudagrass (Cynodon dactylon (L.) Pers.) Invasion

Derald A. Harp; David Kee; Kristen Herschler; Kevin Ong; John J. Sloan


Texas Journal of Agriculture and Natural Resources | 2015

The Effect of Rose Root Size on Drought Stress Tolerance and Landscape Plant Performance

Derald A. Harp; Keisha Kay; David C. Zlesak; Steve George


Horttechnology | 2015

Physical Characteristics of and Seed Germination in Commercial Green Roof Substrates

Derald A. Harp; Cheng Chen; Curtis Jones


Texas Journal of Agriculture and Natural Resources | 2016

Goat Performance and Prolactin Levels as Affected by Tall Fescue Toxicosis

Brittney L. Junell; Derald A. Harp; Joe H. Bouton; David B. Crenshaw


Hortscience | 2006

71) Comparison of Phytophthora Disease Incidence in Composted Pine Bark Mixes to Chemical and Biological Controls

Jennifer Green; Derald A. Harp; Kevin Ong


Hortscience | 2005

113) Quantifying Landscape Microclimates and Related Cold Injury

Shadd Taylor; Derald A. Harp; Kristen McDowell; Roque Lemus


Hortscience | 2004

Effect of Compost Type on Bermudagrass Invasion

Kristen McDowell; Kevin Ong; Derald A. Harp


Horttechnology | 2002

An Updated Hardiness Zone Map for Dallas-Fort Worth, Texas

Derald A. Harp; Edward L. McWilliams; Michael A. Arnold; John F. Griffiths

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David C. Zlesak

University of Wisconsin–River Falls

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