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

Abstract

<jats:p>Landscape roses (<jats:italic>Rosa</jats:italic> 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 well-adapted, 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 the USDA Plant Hardiness 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 low-input, multiyear Earth-Kind<jats:sup>®</jats:sup> 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 (<jats:italic>Diplocarpon rosae</jats:italic>) 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.</jats:p>

Landscape Performance of Buck Roses under Minimal-input Conditions in North-central Texas

“…Disease pressure was highest in the spring, with a recurrence of black spot in the fall, and virtually no disease pressure during July and August. Landscape performance of Buck roses was usually consistent with previous rose cultivar trials in northcentral Texas (Harp et al, 2019;Mackay et al, 2008;Zlesak et al, 2017). In this study, several rose cultivars performed well, especially April Moon, Freckles, Carefree Beautyä, Red Dream, Square Dancer, Prairie Breeze, and Country Dancer, whereas others performed poorly.…”

“…2008; Zlesak et al, 2017), with the best performance and heaviest blooms found in spring (April and May), with plant recovery and a second bloom occurring in the fall (September and October). Disease pressure was highest in the spring, with a recurrence of black spot in the fall, and virtually no disease pressure during July and August.…”

“…2009) for 1) landscape performance; 2) bloom number; 3) percent bloom coverage, defined as the estimated percentage of the plant canopy covered in blooms; and 4) drought stress. Carefree Beautyä was a strong performer in previous studies in northcentral Texas (Mackay et al, 2008;Zlesak et al, 2017) and used as an experimental standard.…”

“…Carefree Beautyä has been recognized as a strong performer under low-input conditions in the south-central United States, and it was designated by Texas A&M AgriLife Extension Service as the Earth-Kind Ò Rose of the Year in 2006 (Texas A&M AgriLife Extension Service, 2019). Carefree Beautyä is also a strong performer in north-central Texas, selected as the control cultivar planted in multiple rose cultivar trials (Zlesak et al, 2017;Zuzek et al, 2016).…”

“…Unfortunately, other than Carefree Beautyä, little information is available regarding the use of Buck roses in warmer climates. Identifying roses with strong landscape performance, resistance to pests and diseases, and a tolerance for the heat and drought common in north-central Texas can be difficult (Harp et al, 2019;Mackay et al, 2008;Zlesak et al, 2017). The objective of this study was to evaluate a selection of Buck roses under minimalinput conditions in north-central Texas.…”