CSU announces annual Flower Trial Garden’s 2021 winning flowers

The 2022 gardening season is almost upon us. 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.

Winners now available for 2022 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 2021 evaluation are now available at area nurseries and garden centers for the 2022 home gardening season.

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 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.

The following is a list of the 2021 “Best Of” Annual Flower winners. The complete list and report, including high-resolution photographs, can be found at www.flowertrials.colostate.edu.

“Best of” Overall Winners

Best of Show – Rudbeckia Sunbeckia Ophelia from Flamingo Holland/Bull

Gigantic yellow flowers glow in the sun and attracted attention from across the garden. The huge flowers create a near solid canopy of yellow color that creates enormous flower power. Foliage that is visible is very attractive and clean. Plants require no pinching and matures at a nice medium height. The long lasting flowers keep a fresh look and stay low maintenance by “burying its dead”. Performance was excellent both in ground and containers.

Best Novelty – Heliotropium Augusta® Lavender from Proven Winners

Prolific flowering was sustained throughout the entire growing season. The soft lavender flowers were very showy and had a slight fragrance in the heat of the afternoon. Plants had good uniformity and were a favorite of pollinators.

Best New Variety – Bidens Brazen™ Imperial Luck from Syngenta Flowers

The vigorous plants were densely branched and created a solid mound of flowers across the canopy which created an impressive display of color. Blooms maintained a uniform pattern and had a rich saturated red color that paired well with the dark green foliage. This entry was also very popular among the bees.

“Best Of”  by Class

Angelonia (both container and ground) – Archangel™ Dark Rose from Ball FloraPlant

Noted for excellent performance in both container and ground, it was a standout with a great display of large clusters of flowers and a tall upright growth habit. Plants had good vigor and control for a very uniform appearance which lasted late into the season. The abundant flowers also had a nice dark eye for added interest.

Begonia (container, upright) – BK Collection Vermillion Hot Pink from Beekenkamp

Strong flowering was maintained all season and was very showy with vibrant shade of dusty rose. Dark foliage helped make the flower color “pop” but double petals and prolific blooming provided a lot of color to a shady location. Foliage was clean and flowers were self cleaning to keep a fresh appearance with low maintenance.

Begonia (container, seed) – Nonstop® Joy – Orange from Benary

Vibrant orange flowers never faded and created a nonstop display of color all season. Flowers were huge and beautiful with the radiant orange color. Entire series received high marks from the evaluators. Trailing growth habit would work well in containers and it is was also reported to grow well in partial sun as well as shade.

Begonia (container, trailing) – Shine Bright White from Westhoff

Vigorous plants cascaded over the sides of the containers with elongated white flowers for a nice combination of color and unique texture. Growth habit was very uniform.

Begonia (Rex) – Jurassic™ Pink Splash from Ball Ingenuity

Great foliage provided a lot of interest all season even without flowers. Pink shades flow down along the center of the leaf with a very nice silver and green on the outer leaf. The large leaf size and unique colors stands out from many other garden plants. Plants had good vigor and uniformity.

Begonia (wax, ground) – Tophat™ Rose Bicolor from Syngenta Flowers

Considered by some as the “best bicolor wax begonia ever”, the huge flowers were excellent basis for that claim. The white and rose flowers were really quite enormous and prolific. The plants in general also had great vigor, uniformity and were well branched.

Bidens – Brazen™ Imperial Luck from Syngenta Flowers

The vigorous plants were densely branched and created a solid mound of flowers across the canopy which created an impressive display of color. Blooms maintained a uniform pattern and had a rich saturated red color that paired well with the dark green foliage. This entry was also very popular among the bees.

Calibrachoa – Cabaret® Good Night Kiss from Ball FloraPlant

Flowers were stunning with a bright pink/purple outer flowers with a very dark center and a yellow throat. The intense color is made even more vivid against the dark green foliage. Plants were dense, with a nice uniform, mounding growth habit.

Coleus – Main Street Orchard Road from Dummen Orange

Plants had good vigor and maintained a consistent growth habit all season. Foliage color was an attractive bicolor of different shade of red in the main leaf blade and a nice contrasting pinstripe of bright green along the outer edge. Flowering was nonexistent until a few late in the season but was still very attractive overall.

Combination – Kwik Kombos™ Blue Lightning™ Mix Imp. from Syngenta Flowers

Dark blue scaevola and bright golden lantana were mixed together for a very effective contrast between light and dark. The plants made good combination that had both good heat tolerance and prolific flowers all season.

Dahlia – City Lights™ Purple from Selecta One

This was a favorite plant from the voting on Consumer Day as well as the industry evaluation due to the abundant rich, dark purple flowers and dark foliage. The consistent appearance was aa reason for it being a repeat winner from 2020. Plants were uniform in habit and maintained a fresh appearance by burying its dead.

Geranium (container) – Mojo™ White from Syngenta Flowers

Clean, white flowers stood out against dark green foliage for maximum color contrast. Abundant flowers and the large size made a very attractive presentation. Plants were both vigorous and uniform with clean foliage.

Geranium (ground, Interspecific) – Calliope® Large Orange Splash from Syngenta Flowers

Floriferous plants had huge flowers with vibrant color that created a immense amount of flower power. Color was not a true orange but more of a unique watermelon shade with a darker splash of color in the center of the petal. Flowers were noted to be long lasting for a greater period of show.

Geranium (ground, Zonal) – Galaxy™ Violet from Ball FloraPlant

Plants had good uniformity and vigor. Flower power was excellent with abundant blooms that kept a vibrant violet color without any fading. Plants were tall and were true zonal geraniums with distinct markings on the foliage.

Impatiens – Beacon® Rose from PanAmerican Seed

Clear rose colored flowers brighten the shady spots with their abundant blooms. Growth habit was very uniform and plants had excellent vigor. Full plants had the added advantage of being disease resistant to Downy Mildew disease which can be devastating to many impatiens.

Impatiens (vegetative, sun) – SunPatiens® Compact Deep Red from Sakata Seed America

Large, rich red flowers sat just above the dark foliage for maximum flower power. Plants had a very nice mounded growth habit and great vigor in full sun. They would also work well in a combination with other plants.

Lantana – Hot Blooded® Red from Syngenta Flowers

Blooms had a good rich saturated red color with a touch of orange. Plants maintained a compact and uniform growth habit compared to many other red lantanas. The vibrant red flowers made a good choice for hot locations with minimal water demands.

Lobelia – Hot Waterblue from Westhoff

Plants were noted for incredible vigor and impressive heat tolerance that made it an obvious standout from the other Lobelia even in September. Even late in the season, plants had nice green foliage and an abundance of sky-blue flowers. Growth habit was very uniform as well.

Marigold – Marvel II™ Gold from Pan American Seed

Floriferous plants looked good all summer and even late into the season. The dark green foliage, consistent bloom and uniform growth habit created an excellent overall appearance.

New Guinea Impatiens (shade) – Sonic® Orange from Syngenta

Large flowers were very bright for lots of color in the shade but they can also tolerate partial sun as well. Flowers seemed to sparkle on the compact plants which had good vigor and nice uniformity.

Osteospermum – Gelato Prune from Westhoff

Plants had good flower power even during the heat of the summer. Flowers were very large and a nice shade of dark purple. Overall, the growth habit was uniform and the foliage had a nice green color. The entire “Gelato” series was noted for ranking very high with placing 4 plants in the top 5 rankings.

Petunia (container, vegetative) – Bee’s Knees from Ball FloraPlant

Bright yellow flowers covered the plants for impressive flower power in both containers and the ground. Plants had good vigor and maintained a nice growth habit in the ground or trailed over the container without opening up in the middle. The two toned yellow flowers had proven a dependable performer over the past years and are a repeat winner.

Petunia (ground, seed) – E3 Easy Wave™ Blue from PanAmerican Seed

Vibrant purple/blue flowers provided a blanket of color in the ground with spreading plants and abundant flowering. Besides having good landscape performance, plants were also noted for desirable grower features such as being early to flower and the need for less plant growth regulators.

Petunia (ground, vegetative) – Supertunia Vista® Bubblegum® from Proven Winners

This annual has become a perennial favorite as it has been a winner over several years. It has become the standard that many other varieties have difficulty matching. Plants had incredible vigor and were covered in bright pink blooms that made it easy to spot even from a long distance in the landscape.

Portulaca (container) – Mega Pazzaz™ Purple from Danziger

Intense violet flowers were abundant and held close to foliage to keep a very compact and uniform growth habit. Blooms were single and were very popular with the bees. It was very tolerant of the summer heat and looked great all season.

Portulaca (ground, seed) – Sundial Pink from Benary Plus

Vigorous plants did well in the ground and they maintained a consistent growth habit with a uniform appearance. Double flowers made it very showy and it was very popular with the bees.

Rudbeckia – Sunbeckia Ophelia from Flamingo Holland/Bull

This spectacular plant was also selected the “Best of Show” winner for 2021. Gigantic yellow flowers glow in the sun and attracted attention from across the garden. The huge flowers created a near solid canopy of yellow color that created enormous flower power. Foliage that was visible is very attractive and clean. Plants required no pinching and matured at a nice medium height. The long lasting flowers kept a fresh look and stayed low maintenance by “burying its dead”. Performance was excellent both in ground and containers.

Scaevola – Indigo Touch™ from Danziger

Plants had plenty of “Wow” factor with the large amount of flowers and an amazing, intense blue color. Flowering was prolific and it was maintained all throughout the season. The growth habit was upright, mounding and very uniform.

Verbena (container) – Lanai® Upright Twister™ Watercolor from Syngenta Flowers

Flowers had a unique combination of soft lilac pink with darker shades in the middle. Plants looked good in containers with strong vigor and an upright mounded growth habit that did not open up over the entire season.

Verbena (ground) – EnduraScape™ Pink Bicolor from Ball FloraPlant

Light and dark shades of pink created a very attractive flower and combined with a large, spreading plant made it a great display of color. The uniform habit and great vigor made a good choice for the landscape. It was a good plant for the variability of the long season with good heat tolerance in the middle of summer and good cold tolerance as fall approaches.

Vinca – Soiree Kawaii Coral Reef from Suntory Flowers

Prolific, small pink flowers created a very delicate appearance but maintained a lot of flower power all season. The small pink flowers also had a white eye for added interest and plant did well in both the ground and containers. Plants had nice vigor and good uniformity.

Zinnia – Profusion Red Yellow Bicolor from Sakata Seed America

Flowers were very unique in that the color starts out as a bright red center with golden yellow on the outer petals orange then fade to shades of beautiful apricot and dusty rose. It was a show stopper and a fun plant to watch as flower color changes. Plants were compact and very floriferous.

Other Outstanding Plants

Jamesbrittenia Safari™ Dawn from Proven Winners

Prolific flowering was one of the traits that made this entry standout along with the gorgeous flower colors of soft apricot to rose that changed as it matured. Plants were vigorous and almost enveloped the container in flowers by the end of the summer. Growth habit was uniform and the plant was heat tolerant. It was considered a breakthrough in Jamesbrittenia.

Marigold – Panda Yellow from JYK Seed Co.

Full, double flowers topped the sturdy and uniform plants which created a very good display over the entire season. Plants were medium height and had good dark green foliage. There was no lodging even with overhead irrigation.


The trial evaluation was held on August 3, 2021.  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 (i.e. not hidden by the foliage)
  • Color uniformity
  • Stable color (resistance to fading) and stable pattern (for bicolor)
  • Flower size and uniformity of flowers
  • Balance of color in a mixture

Overall Presentation:

  • Overall “clean” look, versus visible spent blooms
  • Fragrant flowers and/or foliage
  • Good vigorous growth
  • Resistance to climatic stress
  • Novelty value of unique features
  • Overall consumer appeal

Plant varieties were rated on a scale of 1 to 5 (1 = very poor performance; 5 = excellent performance).  These numerical evaluations were used to calculate the average ratings for each variety in the trials.  Participants were to use their tablets or cell phones to electronically evaluate the plants.  The pre-generated comments they could choose from included: 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 August 3rd, 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 was given to classes whose top-five list had ratings of at least 3.0 and one of them could be considered superior.  A sub-committee of university and industry representatives revisited the garden on September 10th to review the top-five list and verify the superiority of the top rated varieties later in the season and not just on August 3rd.  A majority vote was taken for each class to determine the final selections for winners.