Hydrangea paniculata is available wholesale as a cut stem from the Holland market. Some H. paniculata are available in this country as a cut stem through farmers’ markets. A national commercial wholesale source of this stem is not readily available. H. macrophylla cultivars are the flowers that are usually grown for the cut flower market. The other hydrangea species H. arborescens, smooth hydrangea; H. paniculata, panicled hydrangea; and H. quercifolia, oakleaf hydrangea, have been grown for landscape plants (1). Therefore, the ability to produce quality field-grown cut stems of the H. paniculata flower has the potential to offer an alternative income source to Kentucky farmers.
    
In 1999 a hydrangea cut flower cultivar trial was established at the University of Kentucky Research and Education Center at Quicksand, KY (2).
    
In 2001 preliminary studies were conducted at the University of Kentucky to determine the effects of irrigation and pruning influence on hydrangea for fresh cut flower production (2). Cutting the existing H. paniculata shrubs back in the fall produced strong straight stems the next season that definitely had potential for the cut stem market. In 2002 a preliminary study was conducted to see if H. paniculata cultivars had the potential to become a specialty cut flower. The results were reported at the 2002 SNA Conference and showed an average vase life of 5-6 days in 2002. The overall objectives of this experiment was to observe H. paniculata ‘Kyushu’ to see if it has a reasonable vase life, interactions with the floral preservatives and extender, and to see if the stems responded differently to cold treatments.   
    
No information could be found on the best floral preservative to be used on these plants, nor was there any information on the effects cold wet storage would have on these stems. Cold storage could mimic the effects of shipping time as well as the ability of a wholesale florist to “hold” the plant material.
    
The study was initiated when one hundred and fifty stems were harvested on September 16, 2003 at 9:00EST.  Stems were harvested when the first and second row of sterile florets were fully developed.  Dry stems were transported to the lab and measured for an average stem length of 36”.  Stems were then placed into a hydrating solution (Pokon Professional #2) for 1 ½ hours. The ‘Kyushu’ blooms were then divided up into two 75-stem lots to be placed into their no-cold storage treatment and cold storage treatment. The 75 stems for the cold storage treatment were placed into Procona containers for wet storage at 35F and 90% relative humidity for 7 days. The other 75 stems were then placed directly into their treatments which were designated by a randomizing table.  

The eight treatments (per package directions) were:  

1. Control using tap water with a pH of 7.5  
2. Floralife Original Flower Food  
3. Pokon & Chrysal Professional #3
4. Aquaplus per package directions A floral extender which claims to add days of life to the flowers was added to the floral preservatives.  
5. Floralife + Flora Novus XL  
6. Pokon & Chrysal Professional #3 + Flora Novus XL  
7. Aquaplus + Flora Novus XL    
8. Flora Novus XL
    
Stems remained in the treatments until the stem tips wilted or the sterile florets showed the first brown color and the flowers were no longer of any commercial value. For example, if the stem in vase 3 failed to rehydrate and remained wilted after initial treatment the vase life was considered 0 days.  If the sterile florets started browning on the third day vase life was over and considered to be 3 days.  The stems that remained in cold storage for 7 days were then taken out of the cooler and were placed into their designated treatments as described with no cold treatments.
    
The experiment was set up as a factorial experiment with replication using a ANOVA to find out the main effects and interactions that occurred with a P value <.05.  The independent variable was the vase life.  The three factors involved were the cold storage, preservative treatments, and extender.  Wet cold storage for 7 days does seem to have a negative effect on the vase life of ‘Kyushu’(Figure1), as vase life was decreased  by 2 days.   Stems with no cold storage treatments had a vase life of 7.9 days and stems in cold storage treatments show a vase life of 5.8 days
(Figure 1). See figure 1 on next page.

The results back up the idea that the cultivar would react differently (Figure 2). Floralife treatment with no cold storage treatment was significantly better than either of the two preservatives or the control (Figure3). When stems were stored in cold prior to treatment there was no difference between preservatives, although preservatives were better than control (Figure 4). The cut flower responded to the extender and floral preservatives + extender by actually decreasing the vase life by 1-2 days. The following is a suggestion for future research to determine the maximum vase life of H. paniculata. First, how long can these flowers remain in dry cold storage before their viability is adversely affected?  Does shipping and storage in a solution vs. dry cold storage make a significant difference in vase life?   

Results of this study indicate that H. paniculata ‘Kyushu’ has the potential to be a fresh cut flower. Implementation could potentially develop a supply of H. paniculata for the wholesale fresh cut flower market. Controlling production practices, Storage methods, and preservation solutions can resalt in a hydrangea fresh cut flower market crop not normally available for growers interested in alternative farm incomes.

Literature Cited:
1. Armitage, A.M and Judy Laushman. 2003. Specialty cut flowers. 2nd ed. Timber Press, Portland Ore.

2. Dunwell Winston, Dwight Wolfe, and June Johnston.2001. Hydrangeas for cut flowers: 2000 observations. UK Nursery and Landscape Program 2001 Research Report, PR-450:8-9.