Plant Trials in Iowa

Seizing the opportunity to provide Iowans information about newly introduced plant varieties, the Iowa Arboretum & Gardens began a perennial and shrub plant trial program in 2023. The purpose of this garden is to evaluate the long-term performance of these plants and report the findings to the public and the horticulture industry. Over time, this garden becomes more and more of a library for you to use as a resource for researched recommendations for Iowa gardens! Ultimately, the most successful plants get recognized as Top Performers by the arboretum.

Plants are evaluated on a weekly basis using these factors to help measure their success:
● Vigor (Compared to plants in the same genus/species, no lodging)
● Uniformity (Across plants in a variety)
● Disease/pest resistance (Comments about pest and disease pressure, rabbit resistance, susceptibility to disease compared to claims)
● Floriferousness (Qualitative rating of flower coverage)
● Proliferation (Seediness, weediness, potential to become invasive)
● Resilience (Ability to withstand drought, flood, unpredictable weather events)
● Seasonal Interest (Gives weight to unusual flowering period, fall color, and winter interest)
● Survival (Ability to survive growing conditions, lifespan evaluation)

Evaluation will be conducted for the life of the plant, giving us realistic understanding of the lifespan and true hardiness of varieties. However, plants will be selected as Top Performers after three years for perennials and five years for shrubs.