Annual Flower Trial Garden’s winning flowers


The 2016 gardening season is almost upon us.  If you want to know what flowers to plant this growing season, a list of great possibilities come 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.

Gardening Season 2016

“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 2015 evaluation are now available at area nurseries and garden centers for the 2016 home gardening season.  For more detailed descriptions and photographs, visit

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.


The trial evaluation day was held on August 3, 2015.  Approximately 100 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 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 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 6.0 and one of them could be considered superior.  A sub-committee of university and industry representatives revisited the garden on September 11th 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.  “Other Outstanding Plants” was 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 partial list of the 2015 “Best Of” Annual Flower winners and the complete list and report can be found at

Best of” Annual Flower Winners from the 2015 CSU Trials

 Best of Show Sun New Guinea Impatiens  ‘Sunpatiens® Spreading Tropical Orange’ from Sakata
This winner was near perfection in every way.  Electric orange flowers were vivid and had a great contrast against the beautiful foliage.   Plants maintained a high level of flower power all season.  It had impressive vigor while the growth habit was very uniform.  Foliage was very attractive all by itself with a dark green edge and bright yellow center.  Plants grew well in full sun but are also adaptable to light shade.

Best NoveltyCelosia ‘Dragon’s Breath’ from Sakata
This plant garnered a lot of praise even before it started flowering for its beautiful burgundy colored foliage.  Flowers formed late but were definitely worth the wait as they had a two-toned combination of burgundy and hints of fluorescent purple that seemed to glow.   The vigorous plants had good garden presence all season.   It would make a great textural accent for combination plantings.

Best New Variety Lobularia ‘Raspberry Stream™’ from Danziger
Extreme flower power was combined with an intense raspberry color for an impressive flower display.   The unique raspberry flower color was also noted for a nice cream colored eye for a slight two-toned effect which was very attractive.  Overall it had a very uniform growth habit which held its shape and the plants maintained a clean appearance all season.   Bees loved it and it also had a nice, sweet fragrance.

“Best Of…” in Class

Best Begonia semperflorens‘Whopper Red Green Leaf’ from Ball Ingenuity
Beauty is combined with adaptability which makes this plant a great choice for many different landscape situations.  Plants were vigorous with vibrant green foliage and had abundant red flowers which created a stunning image of vitality.  Sun and shade tolerant, these plants are also adaptable for high altitude gardens and a good shade alternative to the recent downy mildew problem on seed impatiens.

Best Calibrachoa‘Superbells® Evening Star’ from Proven Winners
Plants were grown in a container and besides being a massive ball of flowers and color it was also noted for unique flower color that would shimmer in the sunlight.  Flower color seemed to be made up of three different shades of purple with a dark eye.  The growth habit was very uniform and the flowers also were noted for opening up earlier in the day than many other Calibrachoa.

Best Combo – ‘Trixi™ Fairy’ from Selecta
This was a unanimous winner for “Best Combo” and was also considered in the voting for “Best New Variety” and “Best of Show”.   Flowering was excellent from all three different Scaevola in the mix for a very nice color blend.  Described as a “waterfall of color”, the white and lavender was combined with a nice strong pink.  The mix of the three varieties of Scaveola was also very uniform in growth habit.

Best Dahlia –XXL Sunset’ from Red Fox by Dummen Orange
Abundant flowers had very beautiful tropical shades of mango and pineapple color.  Plants were uniform and vigorous.   The cactus flower type would serve a dual purpose as both a landscape plant and a cut flower.

Geranium (Zonal) ‘Allure™ Purple Rose’ from Ball FloraPlant
Bright green foliage made a beautiful contrast with the electric rose flower color.  Blooms were very abundant and constant all season.  Plants were vigorous and very uniform.

Best Impatiens‘Big Bounce™ Lavender’ from  Selecta
The entire ‘Big Bounce’ series was noted as being superior since it had four varieties ranked in the top five but the Lavender selection was selected as the best.   Large lavender flowers covered the large, mounding plant.  It appeared to be resistant to downy mildew and is sure to brighten up a shady area.

Best Lobularia‘Lavender Stream™’ from Danziger
Abundant flowers and uniform growth habit made this plant near perfect.  Flower color was a vibrant lavender color which looked beautiful even as it faded.  The ‘Stream’ series had two other selections that placed in the top five and is a tribute to the strength of the entire series.   Besides combining well with other flowers, it is also bee friendly and fragrant.

Best New Guinea Impatiens‘Magnum Red Flame’ from Red Fox by Dummen Orange
Large red flowers were a standout because of their vivid shade of red and depth of color.  Plants were vigorous, large and very uniform.

Best Petunia (Veg Mound)‘Perfectunia® Orange Morn’ from Westhoff
Flowers were unique with a very beautiful soft orange color complemented by a white and yellow eye.  Plants had prolific flowering as well as being very uniform.  It was noted that blooms still looked very good even as they faded.  This flower would make a good choice for a cottage garden.

Best Petunia (Veg Spread) –  ‘Cascadia Indian Summer’ from Danziger
Unique flower color made this a winner along with impressive vigor and a multitude of flowers.   Blooms had a fascinating blend of colors that included shade of peach, orange and yellow that is a true color breakthrough.   This plant was also a winner in  previous years and has proven to be a dependable favorite.

Best Verbena‘Endurascape™ Hot Pink’ from Ball FloraPlant
A great plant for the landscape with a vigorous spreading growth habit and was covered with many “bright, bright, bright pink” flowers.  Plants were very uniform as well as resistant to mildew.

Best Vinca – ‘Mega Bloom Deep Lavender’ from Ameriseed
Almost all Vinca looked great in 2015 but the ‘Mega Bloom’ series placed four entries in the top five rankings.  The ‘Mega Bloom’ series has a good range of colors but the deep lavender selection was rated the best for its large flowers and vigorous plants.  Plants appeared to be resistant to phytophora.

Best Zinnia‘Zahara® Double Fire’ from PanAmerican Seed
Flower power was extreme due to prolific and very double flowers with fiery orange color.  Plants had good vigor and performed well in the heat.  It was also a past All-America Selections program winner so it performed well in many other places across the country.

Other Outstanding Plants

Lantana ‘Lucky Sunrise Rose’ from Ball FloraPlant
This has been an award winner in the past and has become a perpetual favorite.  The brightly colored flowers were very prolific and the dark foliage color really made the flower color “pop”.  Plants were vigorous but maintained a uniform growth habit.

Verbena ‘Meteor Shower’ from Proven Winners
Delicate, tiny flowers formed balls of blooms held up high on tall stems that create a nice effect in cottage gardens.  Flowering was prolific and long lasting.  Plants were well branched and uniform with an upright growth habit that was knee-high.