The purpose of the trial garden is to evaluate new perennial plant species and cultivars under the unique Rocky Mountain environmental conditions. Plants are evaluated for plant vigor, uniformity, floriferousness and tolerance to environmental and biotic stresses. The Perennial Trial program at Colorado State University is designed to test newer perennial cultivars that have been introduced in the past three years or less. Entries in this trial are grown for three summers and two winters before they are switched out for new entries.
About the Trial Garden
CSU’s Flower Trial Garden, which draws thousands of visitors each year, relies on student gardeners, volunteers and industry supporters and experts who help provide detailed analysis of plant performance. Colorado State Extension master gardeners play an essential role in planting and maintaining the garden. The outcome of this research is valuable to the industry and home gardeners alike. That’s because the Rocky Mountain region has unique growing conditions, characterized by high altitude, intense solar radiation, drying winds, severe hailstorms, large fluctuations between day and night temperatures and a season-long need for irrigation.
The Perennial Trial Garden receives no direct state or public funding. It is funded primarily by fees from plant-breeding companies that submit entries to the trials. The garden also receives donations from industry associations, foundations, nurseries, plant producers and other companies in the green industry.
Performance Evaluation
Photos and data on plants and flowers were collected on a bi-weekly basis from May to early October. Dead plants in the trial were not considered in the bi-weekly evaluation; thus, the ratings given only reflect the live plants. Members from the Perennial Trial subcommittee also evaluated and wrote comments for each plant variety in June, July, August and September. Plants and flowers were rated 0-5 using the following scale:
0 = Dead/No flowers
1 = Poor: Plants are very sick or dying, extremely few flowers
2 = Below Average: Plants are unattractive in some form, i.e. – leggy growth habit, chlorotic or low vigor, flowers are few and occurring sporadically
3 = Average: Plant appearance with growth characteristics that would be expected for the time of season; flowers would be few but uniform across the plants
4 = Good: Plants look attractive (foliage, growth habit, etc.,); flowers are blooming strong and showy
5 = Excellent: Plants are very healthy and uniform; flowering is impressive
Selection of ‘Top Performers’
On Nov. 16, 2018, a conference call was convened with CSU staff and the Perennial Trial Garden Subcommittee. Pictures of entries from the 2016 planting were posted to the Perennial Trial website for review. Data from the growing season was compiled and emailed to each evaluator prior to the conference call for review. After discussion and looking at the pictures taken throughout the season, each plant was voted on by each member of the committee as to whether it should be awarded the designation as a “Top Performer”.