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                    Flowering Dates and Phenology Study

     Peony Phenology in Alaska 2012. by Patricia S. Holloway, Grant E.M. Matheke and Katie DiCristina. Poster. Presented at the Alaska Peony Growers Association Conference. 13-15 February. Fairbanks, AK. PDF

     We installed Hobo dataloggers at peony farms around the state and asked growers to note the date of the following phenophases: first bud emergence on one of five ‘Sarah Bernhardt’ peonies; bud emergence on all five plants; date of first color; and date of first cutting. The number of degree-days accumulated for each phenophase (first cutting, first color, etc.) is also similar across sites. These data hint that we will be able to use degree-days in modeling peony growth. In the future, growers might be able to predict bloom times by the number of days or TDD after bud emergence. The number of days within each phenophase differed radically among sites. The hotter Fairbanks sites completed bud emergence to flowering in as little as 32 days, while the cooler coastal and south central sites took more than twice as long. Early season bud emergence occured in mid to late May at each site. The biggest difference occurred in the time between bud emergence on all plants and first color (Figs 3 - 4). Flowers growing in south central and coastal Alaska took up to four times longer to reach the first color stage than those in the Interior. These data show that peonies are strongly influenced by air temperature. With a few more years of data, we may be able to predict bloom times very early in the season by calculating degree-day accumulation.

The University of Alaska Fairbanks Georgeson Botanical Garden, PO Box 757200, Fairbanks, Alaska 99775 (907) 474-7222, gbgardensuaf@gmail.com