ASHS 2015 Annual Conference

Two peony cultivars, ‘Sarah Bernhardt’ and ‘Duchess de Nemours’, were treated to a series of cold treatments (0–168 hours in 2013 and 0–336 hours in 2014; 24- and 48-hour intervals, respectively) at 1.5 + 2 °C to establish the minimum time necessary for chilling prior to shipping for maximum consumer vase life. Preliminary research found that chilling for 1 week, doubled the vase life, and data from 2013 season corroborated those findings. However, vase life for cut flowers in 2014 decreased significantly and did not improve with chilling. Vase life for ‘Sarah Bernhardt’ and ‘Duchess de Nemours’ peonies averaged 6.1 days and 5.9 days, respectively, for the entire treatment period and did not differ from the unchilled control. This research did not clearly identify minimum chilling requirements for Alaska peonies. In contrast, cut stems in 2013 showed a linear increase in vase life with chilling (8.2–14.2 days for ‘Sarah Bernhardt’ and 6.9–13 days for ‘Duchess de Nemours’. Vase life and bud diameter did not differ among early- mid- and late-season cutting dates for both cultivars. Cut stems from two commercial farms showed the same short vase life, and there was no statistical difference in vase life among farms. Environmental factors during spring growth or postharvest handling differences play a more significant role in defining vase life than simply hours of chilling.  Vase life for 68 cultivars (7 days, 1.5 + 2 °C)  in 2014 ranged from 4–9 days (mean 6.0 + 1.0 days).  In 2013, vase life averaged nearly three days longer, 8.6 + 2.7 days (range 4–14 days). Vase life for 2014 was significantly lower for most cultivars than 2013. In 2013, more than 70% of the cultivars showed an average vase life of 7 days or more, while in 2014, only 24% reached that standard. The four main classifications of peonies, semi-double, Japanese, bomb, and full double, had an  average vase life ranging from 5 to 17 days. One class had a vase life of less than 7 days for both 2013 and 2014, the Intersectional hybrids.