Trial garden report: Season wrap-up in Colorado

The Colorado State University (CSU) Flower Trial Garden can be visited year-round, with some cool season crops blooming in early spring, and many annuals planted in May don’t fade away until October. Two perennial gardens also highlight new introductions and tried-and-true favorites.

The 2024 CSU trials wrapped up for the season at the end of October 2024. Chad Miller, assistant professor and CSU Trial Gardens director, said for much of the summer, the Fort Collins area was under abnormally dry to moderate drought conditions, and Japanese beetles remained an issue during the season.

In the 2024 season, 22 seed and vegetative companies participated in CSU’s trials.
“In total, we had almost 1,000 entries planted in containers and/or in ground beds, in sun or shade conditions,” said Miller. “There were lots of great-looking plants this summer — making it a bit difficult to choose the best plants! The lantanas, geraniums and dahlias put on great displays.”

Visitors are encouraged to vote for their favorites when visiting throughout the summer. Here are some winners from both industry evaluations and public voting.

There are many new and improved petunia varieties to choose from, but one that stood out this summer (and was a personal favorite of Miller’s) was Beekenkamp’s ‘Tea Flamingo’ petunia (shown in the featured top image). It flowered all summer, well after many other petunias started to fizzle, he said. The plants were well-branched and have a more upright growth habit, great for container and landscape plantings.

Dahlias continue their popularity with visitors, earning the top pick again this year. ‘City Lights Purple’ dahlia from Selecta One is bred for performance in heat and holds up in full sun all season. It flowered through the summer with rich, deep mulberry-purple flowers that are accentuated by the dark green-black foliage, Miller said. Bees and pollinators also favored this plant.

Another fan favorite was the fan flower, scaevola ‘Scala Purple Bird’ from Dümmen Orange. “When we mention flower power, this plant does not hold back,” Miller said. “It was a solid patch of deep purple in the landscape all summer; compact and clean flowers and foliage make this a winner.”

Lantanas made the list for their ability to handle heat and lower water inputs; plus, they are great pollinator magnets. ‘Bandolista Mango’ from Syngenta Flowers was the best-performing lantana at CSU. It had loads of vibrant flowers in shades of yellow through red; one could barely see the foliage when it was in full bloom, Miller said. Moderate vigor, habit, and tolerance of low water make lantana a great option for containers and hanging baskets, besides the landscape.

Another plant in the trials this summer that wasn’t a new kid on the block but packed a punch was Fireworks gomphrena from PanAmerican Seed, said Miller. “It definitely provides that pow effect in the gardens all season, handling the heat and sun,” he said. “We had an extra space in the trials and we got a bit creative and paired Fireworks with silver dollar plant (Plectranthus argentatus), creating a great border combo!”