If you drive by Colorado State University’s Annual Flower Trial Garden on August 7, you’ll notice a horde of individuals, armed with clipboards and electronic devices, roaming around. They’re green industry professionals, CSU Extension master gardeners, and university faculty, students and employees, all participating in evaluation day.
The evaluators’ task is to rate more than 1,000 new cultivars of annuals on uniformity (whether all plants of the same variety look similar), vigor, floriferousness (number of blossoms), and tolerance to environmental and abiotic stress (sunlight, day/night temperature extremes, soil pH, clay texture, etc.).
Once the results are tabulated, the winning varieties for 2018 will be posted on the CSU Flower Trial Garden website.
Evaluation day represents the yearly culmination of trialing efforts at CSU. In the spring, growers from around the country ship cuttings to CSU, where students, employees and master gardeners transfer them to 4” pots at CSU’s state-of-the-art greenhouses so the growing can begin. Seed companies send their newest offerings to Denver’s Welby Gardens, where the seeds grow into small plants under controlled conditions.
In late May and early June, CSU students, employees and master gardeners transplant most of the seed- and cutting-grown plants into pre-dug holes in the ground. The plants and planting areas are carefully labeled to ensure that the right plants end up in the right holes. The planting area is regimented, with two rows of nine plants of each new cultivar installed next to other new cultivars of the same type and similar color. For example, 18 red geraniums from, say, Proven Winners might be planted next to 18 red geraniums from, say, Dummen Orange. That makes it easier for evaluators to compare one red geranium variety to another.
Besides planting in the ground, workers also install many of the plants in large pots with about five plants per pot.
Sometimes hail storms and other environmental events occur that can wipe out new plants. For that reason, CSU grows backup plants and stores them in its greenhouses.
Among my favorite annuals this year are Green Fuse Botanicals’ Kanga Jump Red Anigozanthos (the beloved kangaroo paw from Australia), Proven Winners’ richly colored and highly textured ColorBlaze Torchlight Coleus, Dummen Orange’s Confetti Garden Cupcake Smarty Party Portulaca, Floranova’s Apollo Pink Cosmos, and Danziger’s Lia Mix Calibrachoa.
Dr. James Klett, CSU professor of landscape horticulture, and David Staats, department of horticulture research associate, supervise the operation of the annual trial program.
CSU’s garden is one of about 80 trial sites throughout the U.S. and Canada. The yearly trial is operated as part of the All-America Selections program, whose purpose is to test new, unsold cultivars; inform gardeners about the winners; and instill trust in AAS winners.
Besides trialing annuals, CSU also trials perennials and cool-season plants, such as violas and pansies.
So, if you want a leg up on the latest plant varieties, visit the trial garden. You probably won’t be able to buy your favorites right away. But if they do well in the trials, you’ll likely find them in your local garden center within a year or two.