Performance of Garden Roses in North-central Texas under Minimal Input Conditions

One hundred sixteen rose (Rosa spp.) cultivars were evaluated under minimal input conditions in north-central Texas for 3 years. Plant quality data included overall plant performance, number of flowers, percentage of bloom coverage, final vigor, and survival. Disease ratings for black spot (Diplocarpon rosae), petal blight (Alternaria alternata), powdery mildew (Sphaerotheca pannosa), and aphid (Myzus spp.) infestations were previously reported. Of the original 116 cultivars, 25 had 50% or higher mortality during the trial. Own-root cultivars performed significantly better than the grafted cultivars and had significantly better survival (P = 0.001). As a class, the Polyantha cultivars exhibited the best overall performance, mean bloom percentage, final vigor and survival, while cultivars in the Hybrid Tea class had the worst performance in all measures. Foliar nutrient content, bloom number, and mean percentage of bloom were not good predictors of overall performance. Of the diseases monitored, black spot was the most severe and was closely correlated to overall performance and final vigor, but was not the only factor determining overall performance. The top five cultivars in mean overall performance were RADrazz (Knock Out™), Caldwell Pink, Sea Foam, Perle d'Or, and The Fairy, in descending order.

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Flowering, Drought and Disease Tolerance, and Landscape Performance of Landscape Roses Grown under Low-input Conditions in North Central Texas

HortTechnology ◽

10.21273/horttech04215-18 ◽

2019 ◽

Vol 29 (3) ◽

pp. 234-240 ◽

Cited By ~ 1

Author(s):

Derald Harp ◽

Gaye Hammond ◽

David C. Zlesak ◽

Greg Church ◽

Mark Chamblee ◽

...

Keyword(s):

Disease Resistance ◽

Drought Tolerance ◽

Black Spot ◽

The United States ◽

North Central ◽

Knock Out ◽

Landscape Performance ◽

North Central Texas ◽

Central Texas ◽

The Impact

Landscaping today involves the struggle to balance aesthetically pleasing plants while minimizing the impact on the environment, reducing water usage, decreasing fertilizer use, and eliminating or significantly reducing pesticide usage. Roses (Rosa sp.), although seen as challenging plants, remain the most popular flowering shrub in the United States. The identification of new cultivars that combine beauty, pest and disease resistance, and drought tolerance are important to Texas landscapes. Sixty roses were assessed over a 3-year period to determine flowering, drought tolerance, disease resistance, and overall landscape performance in minimal-input gardens in north central Texas. Atypical weather during the study had a significant impact on performance. A 2-year drought (2010–11) was accompanied by the hottest summer on record (2011), which included a record number of days of at least 100 °F or higher. As a result, supplemental irrigation was provided three times both summers. Roses generally fared well under these conditions and survived the drought. Flowering was most abundant during the spring and fall, and it was least abundant in the summer. Powdery mildew [PM (Sphaerotheca pannosa var. rosae)] was a minor problem. Nine of 60 cultivars developed no visible symptoms of PM during the study. Most PM occurred in Spring 2010, with very little found after June; none was found in 2011. Black spot [BS (Diplocarpon rosae)] was serious for some cultivars, but most were BS-free; RADrazz (Knock Out®) and Lady Banks White had no observed BS during the study. BS occurred mostly in May, June, and November. Overall landscape performance ratings were high, with 23 cultivars having a mean landscape performance rating equal to or better than the Belinda’s Dream standard. The best-performing cultivars were RADrazz (Knock Out), RADcon (Pink Knock Out®), RADyod (Blushing Knock Out®), WEKcisbaco (Home Run®), and Alister Stella Gray. This study was able to identify many other highly performing roses in north central Texas.

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

HortTechnology ◽

10.21273/horttech04539-19 ◽

2020 ◽

Vol 30 (2) ◽

pp. 231-237

Author(s):

Derald Harp ◽

Gaye Hammond ◽

David C. Zlesak ◽

Greg Church ◽

Mark Chamblee ◽

...

Keyword(s):

Black Spot ◽

State University ◽

Alkaline Soils ◽

North Central ◽

Diplocarpon Rosae ◽

Landscape Performance ◽

Wide Range ◽

North Central Texas ◽

Central Texas ◽

Dead Plant

Griffith Buck (Iowa State University) bred roses (Rosa sp.) to survive long, cold winters and hot, humid summers yet still retain their foliage without fungicides. Unfortunately, there is little known about the performance of Buck roses in the southern United States. Thirty-eight Buck rose cultivars were evaluated for flowering, disease resistance, drought tolerance, and overall landscape performance in alkaline soils with no fertilizer, no pesticides, and only limited irrigation. Flowering occurred on a bimodal basis, with the highest per plant mean bloom number (16.3 blooms) and bloom coverage (9.7%) in April, and a second flowering in the fall, with 13.7 blooms per plant and 6.9% bloom coverage in October. Drought stress symptoms were most evident in October, with a wide range of symptom severity across cultivars. Black spot (Diplocarpon rosae) and powdery mildew (Podosphaera pannosa) incidence were rare across all roses and years. Landscape performance scores, rated using a 0 to 10 scale with 10 representing a perfect plant and 0 a dead plant, were highest in April (6.5) and lowest in June (4.6) and July (4.6). Landscape performance was not correlated with bloom number or coverage. While unable to recommend many of the Buck roses for north-central Texas, the cultivars April Moon and Freckles, and possibly a few other roses, can join Carefree Beauty™ (BUCbi) as recommended roses for the area.

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Landscape Performance of Ebony Crepe Myrtle Cultivars in Low-input Landscapes in North-central Texas

HortTechnology ◽

10.21273/horttech04748-20 ◽

2021 ◽

pp. 1-7

Author(s):

Derald Harp ◽

Kevin Chretien ◽

Mariah Brown ◽

Curtis Jones ◽

Jose Lopez-Serrano

Keyword(s):

Sandy Loam ◽

North Central ◽

Low Input ◽

Landscape Performance ◽

North Central Texas ◽

Central Texas ◽

Overall Performance ◽

Intensively Managed ◽

Study Sites ◽

Managed Landscapes

The Ebony series of crepe myrtle (Lagerstroemia indica) cultivars includes several (Ebony Embers, Ebony Fire, Ebony Flame, Ebony Glow, and Ebony and Ivory), marketed today under the Black Diamond® brand. These are relatively new crepe myrtle cultivars unique for their dark foliage, but with little information concerning their performance in north-central Texas, especially in low-input landscapes. The study was conducted from 2014 to 2017 at three locations in north-central Texas with three soil types, an acidic fine sandy loam, a neutral pH silt loam, and an alkaline heavy clay. Although soils and environmental conditions caused variations between sites, overall performance among cultivars was consistent across all study sites, with Centennial Spirit having better landscape performance than any of the Ebony cultivars tested. ‘Ebony and Ivory’ and ‘Ebony Blush’ had the overall lowest landscape performance. Ebony cultivars grew more slowly, had fewer blooms, and were more susceptible to powdery mildew than Centennial Spirit. While the trees may perform better in more intensively managed landscapes, the Ebony cultivars did not perform as well as Centennial Spirit in low-input landscapes in north-central Texas.

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PERFORMANCE OF GARDEN ROSES UNDER MINIMAL INPUT CONDITIONS IN NORTH-CENTRAL TEXAS

HortScience ◽

10.21273/hortsci.40.3.881a ◽

2005 ◽

Vol 40 (3) ◽

pp. 881a-881

Author(s):

W. A. Mackay ◽

C.M. McKenney ◽

P.F. Colbaugh ◽

S.A. George ◽

J.J. Sloan ◽

...

Keyword(s):

Black Spot ◽

Nutrient Concentrations ◽

North Central ◽

Diplocarpon Rosae ◽

Landscape Plants ◽

Environmentally Responsible ◽

Central Texas ◽

Overall Performance ◽

Foliage Quality ◽

Sphaerotheca Pannosa

To enlarge the palette of environmentally-responsible landscape plants, 117 garden rose cultivars were evaluated under minimal input conditions. Other than mulching and irrigation, no other inputs were provided, including no fertilization and no pesticide applications. Plants were established in completely randomized blocks with four reps in the spring of 1998 with data collection beginning in 2000 and continued through 2002. Data on overall performance (an index comprised of flower number, percent of plant covered with flowers and plant growth) and relative chlorophyll content were collected the first and third week of each month from April through October. Disease ratings or incidence ratings were collected for Diplocarpon rosae Wolf (black spot), Alternaria sp. (petal blight) and Sphaerotheca pannosa (powdery mildew). Statistical analysis was performed on the mean data for all dates. `Knockout' was the top rose for overall quality with little or no disease observed, high foliage quality, and continuous flowers from spring until late in the fall. `Knockout' also ranked among the top rose cultivars in terms of overall nutrient concentrations (N, P, K, and Fe) in new growth tissue. Most of the hybrid tea roses such as `Peace' and `Double Delight' died in at least three blocks due to disease and a lack of vigor.

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