Highlights from 2025 Field Trials: Colorado State University
(Information provided by Chad Miller, Associate Professor and CSU Trial Gardens Director)
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Colorado State University (CSU) had more than 1,000 trial entries this year across both ground and container plantings for sun and shade. About 75% of the entries were vegetatively propagated varieties, with the remainder grown from seed.
Temperatures this season were close to average (within one to two degrees), though a few extremely warm stretches occurred in July. Precipitation-wise, we were in a drought situation going into the summer at roughly 50% of the average rainfall. Fortunately, the gardens are irrigated, so the plants did not experience significant water stress.
Our biggest challenge is ongoing Japanese Beetle pressure. Because the gardens are open to the public 24/7, pesticide applications are limited, which in turn restricts our control options and can leave some species and entries looking a bit unsightly at times.
Three Standout Plant Varieties at CSU
Three plants in the trials that impressed me this year were:
Petunia Petunia hybrid Surfinia® Heavenly Cashmere Pink (Suntory Flowers)
Petunia Petunia hybrid Surfinia® Heavenly Cashmere Pink (Suntory Flowers)
This petunia couldn’t have been named any better! The medium-soft pink, iridescent blooms catch the light beautifully and hold their color even in intense sun with no sign of burn. The spreading habit brought a nice form that would mingle and play well with others in a mixed basket.
Black-eyed Susan Rudbeckia hirta ‘Autumn Colors’ (Benary)
Black-eyed Susan Rudbeckia hirta ‘Autumn Colors’ (Benary)
This Rudbeckia brings all the fall feels, just as the name suggests! The plants displayed a beautiful range of colors from warm burgundy and brown tones to deep ochre and mustard yellow. They also showed strong uniformity and good branching. While nearly all other Rudbeckias were showing some signs of powdery mildew, Autumn Colors did not!
Foxglove Digitalis purpurea Hanabee Series (American Takii)
Foxglove Digitalis purpurea Hanabee Series (American Takii)
This group of seeded foxgloves caught the attention of countless garden visitors. The sturdy, vigorous plants produced abundant inflorescences throughout the summer and well into fall, and they were buzzing with pollinators the entire season.
Colorado State University 2025 Best Of Winners
Best of Show
Salvia Salvia hybrid ‘Mystic Spires’ (Ball FloraPlant)
Salvia Salvia hybrid ‘Mystic Spires’ (Ball FloraPlant)
Tried and true! In our evaluation ratings, from 0 to 5, ‘Mystic Spires’ received an almost perfect score! No mystery about it, this salvia is a consistent, show-stopping performer. It was easy to spot the deep blue-purple spires across the garden all season. The sturdy, well-branched, robust plants with deep green foliage were free flowering in the heat of the summer and well into the fall. Plus, this plant is a pollinator’s delight, attracting a wide array of pollinators!
Best New Variety Grown in the Ground
Gomphrena Gomphrena hybrid ‘Fireball Pink’ (Kientzler North America)
Gomphrena Gomphrena hybrid ‘Fireball Pink’ (Kientzler North America)
Talk about eye-catching pink! This gomphrena caught the eyes of a lot of visitors to the garden with its balls of deep, rich pink that danced above the foliage! ‘Fireball Pink’ was never short on color and frequented by our pollinator friends. A great option for mixing into the border, massing, and a container. This spicy annual is a showstopper, for sure!
Best New Variety Grown in Container
Double calibrachoa Calibrachoa hybrid Superbells Magic Double Grapefruit (Proven Winners)
Double calibrachoa Calibrachoa hybrid Superbells Magic Double Grapefruit (Proven Winners)
This calibrachoa has flower power! Flowering all season and well after many other calibrachoa have fizzled out and no deadheading required! Multitudes of soft lemon-yellow double flowers fade to a pastel, pinky, peach color, and scream grapefruit! Everything you like about ‘Pink Lemonade’ — except in double form! A great selection for containers and hanging baskets. AND, in our trials, it performed very well in the ground.
Best Novelty
Snowflake Dusty Miller Centaurea ragusina ‘Silver Swirl’ (Darwin Perennials)
Snowflake Dusty Miller Centaurea ragusina ‘Silver Swirl’ (Darwin Perennials)
If you’re looking to jazz up your containers or add some flair to the border, ‘Silver Swirl’ might be your plant! This plant provides great silver-gray foliage for the landscape, along with interesting texture with its elongated, undulating, dissected leaves. A great plant to contrast and highlight other plants. Also, one of those plants that fits a lower-water-input landscape!
For a full list of Colorado State University’s 2025 “Best Of” trial winners, visit: https://flowertrials.colostate.edu/trial-winner/?y=2025&c=Annual.
For more 2025 field trials information and variety highlights, click here.
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