CSU’s Annual Flower Trials reveal this year’s winners

Contact for Reporters:
Jennifer Dimas

The 2018 gardening season is upon us and if you want to know what flowers to plant this growing season, a list of great possibilities comes from Colorado State University’s Annual Flower Trial Garden.  The garden, which spans nearly three acres on the east side of the Fort Collins campus, is a Northern Colorado showpiece with a focused research and outreach purpose.  Each year, the Annual Flower Trial Garden tests and analyzes the performance of more than 1,000 varieties of annual bedding plants in Colorado’s harsh growing conditions.  Dozens of expert evaluators rate the plants for vigor, growth pattern, bloom and other characteristics.  The trial results help home gardeners identify annual bedding plants that are most likely to succeed.

2018 gardening season

“The Annual Flower Trial Garden – also a vital training ground for CSU horticulture students – is a part of a network of trial gardens at land-grant universities nationwide,” said Jim Klett, faculty coordinator and professor in CSU’s Department of Horticulture and Landscape Architecture.  “It’s the largest garden of its kind west of the Mississippi River.”  Winners from the 2017 evaluation are now available at area nurseries and garden centers for the 2018 home gardening season.  For more detailed descriptions and photographs, visit www.flowertrials.colostate.edu.

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 a 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 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.


The trial evaluation day was held on August 1, 2017.  Approximately 150 judges consisting of industry representatives, master gardeners, university employees and trial garden advisory committee members evaluated the plant varieties for performance using a combination of these criteria:

Plant Quality
  • Uniformity of plant habit
  • Bushy, well-branched shape versus open and leggy
  • Healthy foliage (deep green versus chlorotic, yellow leaves)
  • Foliage texture
  • Disease resistance
Flower Quality
  • Flower power (number of flowers per plant, substance and holding power)
  • Flower presentation (not hidden by the foliage)
  • Color uniformity
  • Stable color (resistance to fading) and stable pattern (for bicolor)
  • Flower size and uniformity of flowers
  • The balance of color in a mixture
Overall Presentation
  • Overall “clean” look, versus visibly spent blooms
  • Fragrant flowers and/or foliage
  • Good vigorous growth
  • Resistance to climatic stress
  • The novelty value of unique features
  • Overall consumer appeal

Plant varieties were rated on a scale of 1 to 10 (1 = very poor performance; 10 = excellent performance).  These numerical evaluations were used to calculate the average ratings for each variety in the trials.  Participants used their tablets or cell phones to electronically evaluate the plants.  The pre-generated comments to choose from include: low vigor, vigorous plant, few flowers, many flowers, uniform, non-uniform, unique color and some chlorosis.

Selection of ‘Best Of’ winners and ‘Other Outstanding Plants’

Ratings from all evaluators on Aug. 1, 2017 were averaged and the top five in each class were placed on a preliminary list.  A class is determined to be any group of plants in the same genus that consisted of 10 or more trial entries.  The “Best Of” award is given to classes whose top-five list had ratings of at least 6.0 and one of them could be considered superior.  A sub-committee of university and industry representatives revisited the garden on Sept. 8 to review the top five list and verify the superiority of the top-rated varieties later in the season and not just on Aug. 1.  A majority vote was taken for each class to determine the final selections for winners.  “Other Outstanding Plants” is an award created to recognize other plants that deserved special recognition; especially for those plants that did not have ten varieties to make up a judging class.  The following is a list of the 2017 “Best Of” Annual Flower winners and the complete list and report can be found at www.flowertrials.colostate.edu.

‘Best of’ Annual Flower Winners from the 2017 CSU Trials

Best of Show – Calibrachoa ‘CHAMELEON® Indian Summer Improved’ from Westhoff

The top award for the 2017 flower trial had eye-catching color combined with great vigor for exceptional flower power.  Varying shades of red, rose, pink and yellow were ever changing to create a dynamic appearance.  The flowers of the CHAMELEON® series are selected for their ability to change color as environmental conditions change which was evident in this selection.  Blooming continued strong all summer and into September.  Plants maintained a uniform growth habit that enveloped the container as a ball of flowers.

Best Novelty – Millet ‘Copper Prince’ from PanAmerican Seed

This plant is an excellent selection for the senses and texture in a garden. It had stout, large, fuzzy panicles of dark rose/bronze rising high above the plant.  The arching foliage had wide blades and plants were very uniform with a unique caramel/copper color during the summer.  This plant would create a very dramatic look in the landscape or in a large container.

Best New Variety – Lantana ‘Luscious® Royale Cosmo’ from Proven Winners

These plants resulted in a great overall appearance with a very uniform rounded growth habit and strong flowering all over.  Flowers had a unique color and were on top of the foliage for maximum flower power.

‘Best Of’  by Class

Argryranthemum – Golden Butterfly™ from Proven Winners

The mass of sunny yellow flowers was very showy and with a deeper shade of yellow than ‘Beauty Yellow’.  Entire series was impressive with flower power and uniformity.  Plants did not stretch and were low maintenance as they “buried their dead” spent blooms.

Begonia semperflorens (Sun) – ‘BIG Red Bronze Leaf’ from Benary

Great vigor combined with strong flowering resulted in an outstanding overall appearance.  Plants had a nice round habit that was very uniform. Flowers covered the plant evenly from top to bottom.  It was a great plant that just keeps getting bigger and better all the way to a killing frost.

Begonia (Shade) – ‘Whopper® Rose With Bronze Leaf Improved’ from Ball Ingenuity

The shiny bronze foliage made an excellent contrast with the prolific rose-colored flowers.  Plant vigor was impressive in the shade and the glossy foliage was large.  Flowers were noted for standing above the foliage and that they did not require any deadheading.  Entire series performed well.

Canna – ‘Toucan® Scarlet’ from Proven Winners

Attractive dark foliage looked good even without flowers.  However, the bright red flowers really stood out against the dark foliage and really made an impressive overall appearance. Plants were very uniform and helped make it the winner of this category for the second year in a row.             

Celosia – ‘New Look Red’ from Benary

Vibrant red plumes maintained color all season for long season display. Dark foliage was another important feature that really made the flowers stand out.  Plants and flowers had good structure and did not lodge.

Coleus – ‘PartyTime™ Ruby Punch’ from Sakata

The foliage was very eye catching with high contrast between the inner shades of dark red and the vivid bright green margin.  Plants were large and upright in habit but with small foliage.  There were no signs of bolting even in mid-September.

Combo – ‘Kwik Kombos™ Shooting Star™’ Mix from Syngenta

This plant was the winner in this category for the second year in a row due to prolific blooming, good structure and high contrast of flower color.  Plants had good heat tolerance and kept blooming strong all season.  Dark purple angelonia was combined with golden yellow lantana that made a beautiful contrast of light and dark.  With a little imagination, it resembled the stars in the night sky.

Cuphea – ‘FloriGlory Manuel’ from Westhoff

This entry was reminiscent of heather and was a great plant to add a delicate texture to the garden or container.  Small flowers and fine foliage combined to make plants with excellent uniformity and appearance.  The dark foliage was a nice contrast to the flowers which had a more intense color than other plants in the series.   

Dahlia – ‘XXL Veracruz’ from Dummen Orange

The stunning display of flowers was a perfect combination of color, large blooms and prolific flowering.  The “cactus” shape flowers had soft shades of lavender and white which would also make good cut flowers.  The vigorous plants maintained uniform growth and resisted lodging with strong stems throughout the season.  This had won awards multiple times in the past five years and has proven itself again in 2017.

Geranium (Interspecific) – ‘Calliope® Large Dark Red’ from Syngenta

An impressive overall visual effect was created by robust plants and abundant large flower heads with rich red flowers and dark flower stems.  Intense flower color held strong even in the high light of Colorado.  Growth habit was exceptionally uniform.  It is considered more of a European style of geranium with smaller plants and large flower heads.  Flower color was iridescent and the overall effect was show-stopping.

Geranium (seed) – ‘Pinto Premium White to Rose’ from Syngenta

This entry was noted for being a novel white and rose bicolor that had large umbels held high above the foliage for maximum show.  Plants had good vigor with foliage that had a good zonation for added interest.     

Geranium (Zonal) – ‘Darko® Deep Red’ from Westhoff

Dark, rich red flowers had great contrast against the emerald green foliage.  Flower heads were large and bloomed all season.  Plants showed good heat tolerance and were very uniform.  Some consider it to be the industry standard for Zonal Geraniums.

Lobelia – ‘Hot® Waterblue’ from Westoff

This variety held up to the heat all summer and still looked good in mid-September.  Growth habit maintained a nice round shape.  Flowers were abundant with a strong blue color that was very attractive.

Osteospermum – ‘Margarita Orange Flare’ from Dummen Orange

Flower color was very unique with a nice chocolate colored eye and flowers were a good contrast with the foliage color.  Plants were compact and uniform.

Pentas – ‘BeeBright™ Red’ from Syngenta

Compact plants had large blooms with a great uniform growth habit.  Flowers were a very intense shade of red that really grabbed attention.  This selection showed good heat tolerance as well as being a good pollinator-friendly plant. 

Petunia (seed spread) – ‘SUCCESS! Pink Chiffon’ from Benary

Soft shades of pink flowers had a touch of cream creating a very romantic appearance.  Flowering was prolific in the container and made a solid blanket of color on the ground.  Plants maintained growth habits with great uniformity.

Petunia (veg mound) – ‘Dekko™ Dark Lavender’ from Syngenta

Dark lavender flowers covered the plants and remained fresh looking with no fading even into mid-September.  Plants had great uniformity, did not stretch and seemed to be disease resistant.  Vigor was very good while maintaining a controlled growth habit.

Petunia (veg spread) – ‘Supertunia® Vista Bubble Gum’ from Proven Winners

This variety has won multiple awards in the past or always in contention.  As one evaluator stated, it is “forever wonderful”.  Plants were extremely vigorous and produced a mountain of pink flowers that were stunning even from a distance.  It made a great plant for landscape or large containers.  It also was disease resistant.

Salvia – ‘Mystic Spires Improved’ from Ball FloraPlant®

Flower display was impressive not only due to the abundant spikes of rich, deep blue flowers but also because they were significantly longer than most other Salvia.  Plants were all very uniform and the flowers looked fresh even in mid-September.  It was an obvious favorite of the bees and a good pollinator plant.

Scaevola – ‘ToppoT Aqua’ from Westhoff

Compact plants had a nice rounded growth habit that was covered with blue flowers.  The flowers were held above the foliage and had a striking blue color that really contrasted nicely with the foliage.  It had an excellent appearance throughout the entire season.

Sun New Guinea Impatiens – ‘SunPatiens® Compact Coral Pink’ from Sakata

Compact plants with great uniformity were a solid mound of pink flowers and a lot of color.  Not much foliage was visible but the dark green foliage made a good contrast with the bright flowers.  Blooms faded attractively from pink to near white for added interest.  This variety has won this class in other years and has proved its superiority again in 2017.  Evaluators were impressed with the entire SunPatiens® series but ‘Compact Coral Pink’ was the best.

Verbena – ‘Lanai® Upright Twister Purple’ from Syngenta

Plants were grown in a container and were covered with a beautiful canopy of large, soft lavender flowers with a white eye.  The many flowers kept “burying their dead” and stayed fresh looking throughout the summer.  The growth habit was very uniform.

Vinca – ‘Cora Strawberry’ from Syngenta

Strawberry colored flowers had a dark eye and were very showy with good contrast.  Color did not fade and it was a low maintenance plant.  Plants were relatively large and very uniform.

Other outstanding plants

 Alternanthera ‘Choco Chili™’ from Westoff

Great foliage color and uniformity made this a great accent plant for the border with its compact spreading growth habit.  The dark burgundy (nearly black) foliage was heat tolerant and looked perfect all season long.  Foliage color had a multi-dimensional appearance due to a lighter ruby color on the underside.

Bidens ‘Blazing™ Fire’ from Danziger

Fiery orange, yellow and red colors were prolific and spectacular.  Plants had great vigor and the dense mounding habit enveloped the container as a ball of flowers with a large “wow” factor.  Plants remained uniform all season and never flopped open.  Flowers opened up darker and faded to a nice yellow.

Calendula ‘Lady Godiva™ Orange’ from Proven Winners

New breeding has created this entry with superior heat tolerance and growth habit.  Plants formed a very compact, uniform blanket of orange flowers that was very impressive.  Beautiful double flowers were a bright, cheery orange with shades of apricot yellow.  Superior heat tolerance was observed on these plants keeping the flowers looking great in July and August.

Calibrachoa ‘CHAMELEON® Plum Cobbler’ from Westhoff

This is another in the CHAMELEON® series that had both spectacular flowers and great growth habit.  Flowers were a very attractive mix of soft shades of plum and yellow which change shades depending on the changes in the climate.  Flower color was unique and pleasing. Vigorous plants created a uniform ball of flowers in the container.

Dianthus ‘Rockin’™ Red’ from PanAmerican/Kieft Seed

Rich, deep red flowers were prolific on plants with a strong upright growth habit.  Vivid colors popped out against the dark green foliage.  It could be used as both a perennial or as an annual with abundant flowers the first year.  It was a good low maintenance plant that did not require deadheading to maintain its appearance.