WCROC Perennial Flower Research

By Neil Anderson, U of MN Horticulture Professor, and Steve Poppe, WCROC Horticulture Scientist 

February 2017

Chrysanthemum researchThe University of Minnesota (U of MN) Herbaceous Perennial Breeding Program is recognized as one of the premiere public-sector flower breeding project programs in the world. Our creation of new chrysanthemum plant habits (from large shrubs to groundcover types), discovery and breeding of reflowering, non-vernalization requiring lilies, release of USDA Zone 4 winter-hardy gladiolus, and cold-tolerant gaura are example research efforts enabling the generation of revitalized floricultural crops for the 21st century. 

The new shrub chrysanthemums resulted in increased U.S. chrysanthemum sales from $104.8M (wholesale) in 2001 (when the first shrub type was released) to $123.65M (wholesale) in 2012, helping make mums the #1 herbaceous perennial in U.S. sales.

Horticulture Advancements

Our advancements in lily breeding have resulted in the creation of colored, seed-propagated hybrids for continued development and domestication. Lilies, which flower under 1 year from seed and continuously flower thereafter, will significantly alter production and use of this crop as a cut flower, flowering potted plant, and garden perennial. Cut flower growers could harvest multiple stems/plant (rather than the standard 1 per bulb) continuously throughout the growing season (field) or in greenhouses (year-round)—rather than having to purchase and force a new crop of bulbs for each harvest. Flowering potted lilies would become dual-use products, enjoyed indoors for a holiday and then reflowered either indoors or outdoors for the growing season. As garden perennials, such lilies would allow for flowering throughout the season rather than just for less than 1 month.

Chrysanthemum ResearchFocus on preventing the creation of invasive ornamental floriculture crops prior to their release onto the market has led to research on contributing factors within the horticultural distribution channel, risk assessment, as well as plant traits to select against during domestication. Reed canarygrass, an ornamental herbaceous perennial, is being used as a model plant in which to study these factors. Continual incorporation of new traits, such as non-invasiveness and drought/heat tolerance will enable continued growth of the floriculture sector with readily adaptable germplasm. Testing for invasive potential of ornamental crops prior to market release must involve genotype-specific testing in multiple sites and locations over years, similar to the methodology used to assess winter hardiness. While costly, the long-term gains in preventing horticultural crop invasions are greater than selling non-winter hardy perennials.

Trials at the WCROC

The West Central Research and Outreach Center (WCROC), Morris, MN, is actively involved with perennial flower trials.  In 2016, we planted and evaluated nearly 175 perennial flower varieties from eight different plant companies.  These companies pay us a fee that helps us with student labor and materials associated with these perennial trials.  All perennials are planted inside one of our 10’ high deer fences so as to avoid any deer browsing.  Four plants of each variety are planted in rows with drip tube irrigation installed in each row.  All plants (if hardy) remain at our trial site for two years; we evaluate the perennials for two summer seasons and two overwintering periods.

During each growing season, the perennials are evaluated based on the following criteria:

  1. winter hardiness
  2. disease or pest susceptibility
  3. height and width measurements
  4. stem strength
  5. flowering-time
  6. reseeding or invasiveness
  7.  vigor

Data evaluation reports are sent to the plant company at the end of each growing season.   They may share that information with the gardening public regarding particular perennial flowers that can grow and perform satisfactorily in our Minnesota plant hardiness zone.