2006 Winter – Production and Vase Life of Red and White Bleeding Heart

Dicentra spectabilis (L) LEM., or old-fashioned bleeding heart, is a well-known perennial garden plant. Its arching racemes have pendulous deep pink or white heart-shaped flowers on naturally long stems. The heart shape and color of the flowers make this plant a perfect choice for use on Valentine’s Day, Mother’s Day or in wedding arrangements.
    
The highest quality plants are produced at cool temperatures of around 70 degree days and 55 degree nights, and thus would require minimal greenhouse heating for late winter to early spring production. The flowers and foliage of D. spectabilis are fragile and easily damaged during long-distance transportation. Potential spring sales,   poor shipping ability, and the possible energy efficiency of cool greenhouse production combine to make D. spectabilis an exciting new specialty crop for local cut flower producers.
    
Dicentra crowns have been brought indoors as a potted plant for earlier flowering since its first introduction as a living plant to England and Europe in the mid-1800’s. It is a native woodland perennial in northern China, Siberia, and Korea and apparently was brought to Japan prior to 1800. Its history as a cut flower is not well documented, but this use is reported to be more common in Europe than in the U. S.. Plants have a mature height up to three feet and a width of two feet. Outdoor bloom time is May – June in the northern U. S. When temperatures exceed 80 degrees, blooming stops. In the garden, recommendations are for full or partial shade. Flowers can be rosy-pink (D. spectabilis) or white (D. spectabilis ‘Alba’ ). It is hardy in U.S. Zones 3 through 8. At least 15 weeks of temperatures less than 45 degrees are required for flower development.                                 

We conducted several experiments over a two-year period to assess the viability of forcing Dicentra spectabilis in the greenhouse for use as a cut flower crop. We were interested in cultural methods (pot size, shade density) and postharvest handling procedures. There is little published research on perennial cut flowers and the effects of pot size or postharvest handling. Shade is known to increase stem length through internode elongation. It also can decrease the number of stems produced. Vase life is, of course, very important for cut flowers.
    
We planted pre-chilled 3- to 5-eye crowns in one, two, and five gallon containers filled with potting soil. They were grown in a greenhouse beginning in January with the temperatures set for a maximum of 65 degrees and 35 degree minimum. Shade was provided by shade cloth suspended over the pots such that treatments were no shade, 47%, and 63% shade. Stems with at least three flowers open and a minimum of five flowers per stem were harvested directly into Floralife Crystal Clear floral preservative and placed in a 35F-degree cooler for 24 hours. Then the vase life was tested using the solutions shown in the tables below. Stems were removed from the cooler, re-cut and QuickDip used before placing the stems in the treatment solution calling for QuickDip. A marketable stem had at least five hearts and a length from the cut base to the first floret of at least 20 cm (about 8 inches) when harvested. Stems continue to elongate and hearts develop after harvest, although not during the time kept at 35F. Mature flowers were indicated by fully reflexed outer petals. Stems were removed from the vase life study when half the open flowers on a stem senesced. Both red and white cultivars were evaluated, with a total of 45 plants of each.
    
The red bleeding hearts produced the most stems under 63% shade, averaging 12.5  inches when grown under shade cloth,  versus 10 to 10.5 inches with less or no shade.  Pot size had no effect on either the number or length of stems in the red cultivar. The white bleeding crowns produced the highest number of stems with no shade (7 stems) or when grown in the five gallon pots. Shade did not affect the stem length of the white racemes, averaging 12.4 inches.  

Both colors of D. spectabilis had longer vase life when a floral preservative was used, mixed as directed on the container with our tap water. In this study, the red bleeding hearts’ vase life in Floralife Crystal Clear solution, with or without a QuickDip treatment, was significantly better than in water with only slight improvement over plain water with either of the Chrysal solutions plus QuickDip. QuickDip did not provide any significant improvement in vase life over the use of a floral preservative.  The entire raceme of red flowers tended to fade within a few days during the vase life study and drop petals as they senesced, whereas the white flowers, as each aged, turned tan, papery, and dropped off. White bleeding hearts also had a longer vase life when a floral preservative was used, regardless of brand or sugar content. Again, the use of QuickDip had no significant effect on vase life of Dicentra spectabilis. The entire raceme of red flowers tended to fade within a few days during the vase-life study and drop petals as they senesced whereas the white flowers, as each aged, turned tan, papery, and dropped off.
    
Production of D. spectabilis as a cut flower crop is promising. Under greenhouse conditions, our recommendation would be to grow the red-flowered form under 63% shade in the greenhouse, while the white form produces best without shade cloth. From two- to five-eye crowns growers can expect a five to six week harvest period and an average of two to three marketable red-flowered stems per crown and four to seven marketable stems from the white-flowered form.  Floral preservative should be used by grower, retailer, and consumer to obtain an average of 12.5 day vase life for the red form and 17.4 day for the white form.
    
Many interesting questions arose during this study as the red and white forms differ in many growth and development patterns.