Rock Star Roses

The American Rose Trials for Sustainability (A.R.T.S.) has added five roses to the family of 75 award-winning cultivars proven to have superior hardiness (disease/pest tolerance, heat/cold/drought tolerance, soil and nutrient adaptability) and plant performance in various regions of the country. A.R.T.S. is an independent, non-profit organization that conducts two-year scientific studies to evaluate the newest roses coming to market and is designed to identify the toughest and most beautiful roses available. The research team (four Ph.D. university scientists, public horticulturists and nursery growers) have decades of experience in conducting plant trials, including at least 40 collective years of scientific rose research.

A.R.T.S. takes the guesswork out of selecting roses that have proven track records of landscape excellence. Nurseries and their customers will find that these award-winning roses require minimal input of resources in return for maximum output of garden performance.

Trial sites and methodology

For 12 years, A.R.T.S. has partnered with organizations across the country that provide space and resources for the trials to take place. All the sites have a strong commitment to scientific plant research and have become regional leaders in environmental stewardship. These sites include six botanic gardens, three cities providing trial sites in public parks, five public gardens and 10 sites associated with universities and/or county extension services. A list of current trial sites is included in Table 1. Each site grows roses under low input conditions (i.e., no applications of fungicides, insecticides or miticides, no deadheading or pruning except to remove winter killed canes at Northern trial sites). A modest application of compost is added to planting beds prior to plants being installed if the soil’s organic matter content is low. No other fertilizer is applied during the trialing period.

Data collection and availability

A.R.T.S. has been working with AgriSciences, Inc. (www.agriscienceinc.com) to create a data platform that will enable faster collection of comprehensive trial data collected in the field using the AgWorld farm management software application. This technology will assist evaluators in quickly capturing key performance information, the presence of pests and/or disease and other trial criteria per the A.R.T.S. protocol, as well as upload photographs on a mobile device directly to the research team.

“Time is definitely one our most precious resources,” explains Jessie Liebenguth, horticulturist at Reiman Gardens (Ames, Iowa; Köppen Dfa). “Using an app designed specifically for trial data collection is a great timesaver for us at Reiman Gardens.”

Evaluators began using the AgWorld app in 2024.

According to Jason Todd, co-founder, AgriSciences is elated to have the opportunity to collaborate with A.R.T.S. in streamlining their data science and managing that data. As data is input into the software program, the data becomes housed in a centralized data depository. The data can be readily queried for real time performance reports along with using the system’s analytical capabilities to help answer questions like suggesting diseases or disorders from photographs that can be confirmed by scientists.

These advances will provide even greater benefits to the nursery industry as well as hybridizers and, by extension, to the trial sites sponsoring regional rose trials.

How awards are earned

Trial plants are evaluated monthly during the growing season using well-defined criteria which includes harvesting data on the presence of disease and pests, flowering, foliage, plant form, growth habit and general health. Each trial site includes the same two ‘control’ cultivars, Double Knock Out (‘RADdko’) and Sunrise Sunset (‘BAIset’), which have proven track records for strong performance across the regions. The average regional performance scores of the two control roses become the threshold score that trial cultivars must meet or beat to earn a regional award. For example, if the average score of the two control cultivars in a region is 6.0, the trial cultivars in that region must have a score of 6.0 or higher to receive an award.

To win an award, roses must prove they are resilient on their own merits without being sustained by repeated fertilizer applications or chemical sprays and are based on the regional performance data collected during the trial cycle. The A.R.T.S. trialing program has two levels of awards. The Local Artist Award is a regional award where a trial cultivar meets or beats the performance scores of the control cultivars in the region tested. Cultivars receiving four or more Local Artist Awards are also awarded the A.R.T.S. Master Rose designation, recognizing a cultivar’s adaptability for planting in many regions. A.R.T.S. award-winning roses are among the most durable and hardy roses for the region(s) in which they won.

Importance of regional adaptability

How regions are determined is important in any plant-trialing program. A.R.T.S. uses the Köppen Climate Classification System to define regions of the U.S. Unlike the USDA Hardiness Zone Map that simply measures minimum temperatures, the Köppen system accounts for temperature and precipitation levels, as well as the timing of each. Temperature and precipitation not only impact plant growth, but also directly impacts the level and intensity of disease and insect pressure. The A.R.T.S. website (www.trustedroses.com) makes it simple to identify different Köppen regions and also identify the roses that have won awards in each region. A list of winners by region may be found on the website under the tab “Climate Zone Map and Winners by Region.” The Köppen system is a comprehensive tool to help A.R.T.S. better answer the question, “Will that rose thrive here?”