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Perennial Trials reveal top 10 performers in Rocky Mountain conditions

April 12, 2014

After three seasons growing in the challenging conditions of the Rocky Mountains, 10 perennial plants have been named "Top Performers" by researchers at Colorado State University.

Perennial Trials Top 10 Performers

(10 images)

Anemone hupehensis 'Pretty Lady Diana' (Pretty Lady Diana Windflower)

Baptisia Decadence 'Lemon Meringue' (Lemon Meringue False Indigo)

Geranium 'Eureka Blue' (Eureka Blue Cranesbill)

Hibiscus Summerific 'Cranberry Crush' (Cranberry Crush Rose Mallow)

Nepeta 'Novanepjun' (Junior Walker Catmint)

Anemone hupehensis 'Pretty Lady Emily' (Pretty Lady Emily Windflower)

Penstemon schmidel 'Blue Riding Hood' (Riding Hoodâ?¢ Blue Beardtongue)

Phlox glaberrima ssp. triflora 'Triple Play' (Triple Play Smooth Phlox)

Salvia nemorosa 'Balyriclu' (Lyrical Blues Meadow Sage)

Agastache 'Blue Boa' (Blue Boa Hummingbird Mint)


From anemones to salvias, these plants have shown they have what it takes to bloom and thrive year after year.

Nearly 40 years ago, Colorado State University established the W.D. Hol­ley Plant Environmental Research Center on the school’s Fort Collins campus, with trial gardens prepared to evaluate annual selections. In 2007, perennial trials were creat­ed adjacent to the annual flower trials in response to increased inter­est in new perennial cultivars.

Evaluating perennials in the Rocky Mountains

The purpose of the trial garden is to evaluate perennial plant species and cul­tivars under the unique Rocky Mountain environmental conditions. Colorado’s growing conditions are 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. Plants are evaluated for plant vigor, uniformity, floriferousness and tolerance to environmental and biot­ic stresses.

For the class of 2013, selections were planted in 2011, requiring that they per­form through two winters and three grow­ing seasons. Data (ratings and photos) were collected every two weeks (May to early October). Plants were evaluated once a month by members of the Perennial Trial subcommittee. The Perennial Trial subcommittee met in October to review data and photos to vote on which entries should be designated a “Top Performer.”

For more detailed descriptions and photographs, visit

'Top Performers' for the 2013 Season

Class of 2011 and Grown in 2013 (2 winters)

Anemone hupehensis ‘Pretty Lady Diana’(Pretty Lady Diana Windflower) - from Blooms of Bressingham

Plants continued to be solid performers.  Plants produced lots of deep pink blooms in August until early October. Pretty Lady Diana Windflower plants were healthy and vigorous. Judges mentioned that the plants would not take up a lot of space and would be great for a small garden or in a mix border. Bred by YoshihiroKanazawa.Planted in 2011.

Baptisia Decadence® ‘Lemon Meringue’ (Lemon Meringue False Indigo) - from Walter’s Gardens/ Proven Winners

Judges stated that Lemon Meringue False Indigo continues to amaze in the 2013 growing season.  They also mentioned that the blooms have a clear crisp yellow flower color. Plants were vigorous and strong. Even though blooms were brief the plants had an open airy habit and nice foliage to enjoy the rest of the season. Planted in 2011.

Geranium ‘Eureka Blue’ (Eureka Blue Cranesbill) - from Blooms of Bressingham

Eureka Blue Cranesbill continues to impress with extreme color impact of bright violet blooms. Judges mentioned that this plant would be a great landscape variety because it looks good even when not in bloom. Plants had healthy foliage all season long. Bred by Brian Kabbes.Planted in 2011.

Hibiscus Summerific® ‘Cranberry Crush’ (Cranberry Crush Rose Mallow) - from Walter’s Gardens/ Proven Winners

Judges stated that Cranberry Crush Rose Mallow continues to be a fantastic grower with dark red blooms and dark glossy foliage. The leaves were deeply lobed and had an attractive dark red hue that matured into dark green. Judges noted that these plants gave the garden a dramatic tropical effect and would be great for late summer color in the back of a border. Bred by Clarence H. Falstad.Planted in 2011.

Nepeta ‘Novanepjun’  (Junior Walker TM Catmint) - from Star Roses and Plants/ The Conard-Pyle Co.

Junior Walker Catmint continued to perform nicely. Vigorous plants were very floriferous with bright lavender flowers. Plants continued to be a great intermediate size at the size of 18 inches in height and 28 inches in width. Plants filled in the space quickly making a great ground cover. Bred by Michael S. Dobres. Planted in 2011.

'New Top Performers' for the 2013 Season

Class of 2011 and Grown in 2013 (2 winters)

AnemonehupehensisPretty Lady Emily’(Pretty Lady Emily Windflower)- from Blooms of Bressingham

This Anemone had great flower power late in the season. Judges stated that the double light pink flowers were unique and that the plants were an amazing flowering machine. Foliage is a dark green and was healthy all season long. Bred by Yoshihiro Kanazawa. Planted in 2011.

Penstemonschmidel‘Blue Riding Hood’ (Riding HoodBlue Beardtongue) - from Pacific Plug and Liner

Judges stated that Blue Riding Hood Beardtongue plants are strong with a good blue flower color. Plants put on a great flower show in June. Plant growth habit was uniform and compact. The foliage was a glossy and medium green in color. Bred by Remy Lubbe. Planted in 2011.

Phlox glaberrima ssp. triflora‘Triple Play’ (Triple Play Smooth Phlox) - Creek Hill Nursery and Eason Horticultural Resources

Judges stated that Triple Play Smooth Phlox serves several functions. The plant’s blooms were pink and complemented the variegated white and green foliage. Even when there are no blooms this variegated ground cover gives interest to the garden all season long. Janet Sacks and Martin Schafer. Planted in 2011.

Salvia nemorosa ‘Balyriclu'(Lyrical Blues Meadow Sage)– from Darwin Perennials

Lyrical Blues Meadow Sage had great flower power with its purple blooms. Judges stated that the plant’s uniformity and clean foliage made the plants enjoyable even when not in bloom. They also mentioned that the blooms are attractive as they age and flower stems keep their color for a long time. Bred by Lynne Knosher. Planted in 2011.

'Too Good To Wait' Performer for the 2013 Season

2012 Class and Grown in 2013 (1 winter)

This category is to acknowledge an upcoming plant that has been in the ground one winter and two growing seasons and has shown excellent performance thus far in the trial. The Perennial Trial Committee likes to award “Top Performer” to plants that have been in the ground two winters and three growing seasons. This plant impressed the Perennial Trial Committee so much that they designated the category name: “Too Good to Wait Performer.”

AgastacheBlue Boa’(Blue Boa Hummingbird Mint)– Terra Nova Nurseries

Judges were impressed with Blue Boa Hummingbird Mint’s nonstop flower power. Plants produced bright lavender blooms heavily throughout the growing season. Judges stated that this plant is drought tolerant, a bee attractor and will bring great joy to home gardeners. Planted in 2012.

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 maintenance of 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 Trial Garden receives no direct 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.

More information

For more information about the CSU Flower Trial Garden, visit