Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 2005
Publication Date: July 7, 2005
Citation: Reed, S. 2005. Evaluation of Styrax japonicus for time of budbreak and susceptibility to spring freeze damage. HortScience. 40:1002. Technical Abstract: Japanese snowbell (Styrax japonicus Sieb. & Zucc.) is an outstanding small ornamental tree that is underutilized in the U.S. Many of the cultivars of this Asian native frequently suffer spring freeze damage, especially when grown in the areas of the country that routinely experience dramatic fluctuations in late winter and early spring temperatures. The objectives of this study were to determine if there was variability within S. japonicus for time of budbreak and if this variability could be used for selecting plants with reduced susceptibility to spring freeze damage. In 1998, 224 open-pollinated seedlings were planted in the field. Percent budbreak was evaluated weekly during a 6-week period in Spring 1999 and 2000. While weather conditions varied greatly between the 2 years, there was good consistency between mean budbreak ratings in 1999 and 2000. There was a 4-week difference between the earliest and latest plants to break dormancy. Based on the 1999 and 2000 data, 28 plants were selected and propagated. A replicated trial involving these selections and three cultivars was carried out in 2002, 2003 and 2004. All of the selections broke bud later and suffered less freeze damage than 'Emerald Pagoda' and 'Carillon', but many performed similarly to 'Pink Chimes'. Variation in height, width, caliper and canopy shape was observed among the selections. There is an opportunity to utilize the genetic variability in S. japonicus for developing cultivars with reduced susceptibility to spring freeze damage.