Dahlias (Dahlia ×hybrida) are a popular specialty cut flower for local production in the United States. Local production is favored, in part, because dahlias do not have a sufficient postharvest lifespan to survive shipping long distances (Armitage and Laushman 2003). Loyola et al. (2019) reported that 73% of cut flower growers produce these tender perennials for their late summer and fall blooms. Wide diversity exists among the ∼20,000 cultivars of dahlias, and most are hybrids (Armitage 2008). Flower colors include yellow, orange, red, pink, lavender, and bicolors. There are at least 29 recognized flower forms, and flower sizes range from less than 2 inches to more than 10 inches in diameter (American Dahlia Society 2023). Of these cultivars, some are grown for landscape use and would not be appropriate for cut flower production because of small plant size or short stem length. Even considering this, growers may choose from a wide variety of dahlias for cut flower production.
Differences in regional weather patterns and climate make it important to trial cut flowers to determine which cultivars are most appropriate in each region (Lewis et al. 2021). This is particularly true for dahlias grown in the northeastern United States because dahlias begin to produce flowers during late summer to early fall, and frost typically ends the production season. Some cultivars, which begin to produce flowers later than others, may have a limited harvest season. Moreover, certain cultivars may produce more flowers or produce flowers of better quality (e.g., flowers with longer stems).
Another challenge with using dahlias as cut flowers is that the vase life is not particularly long; this is a concern identified by specialty cut flower growers (Loyola et al. 2019). In general, it is desirable for cut flowers to have a vase life of ∼1 week; dahlias typically have a shorter vase life of 4 to 5 d when they are held in water only (Bergmann et al. 2018; Dole et al. 2017). This short vase life makes dahlias more suitable for local production and sales, and for use at special events, such as weddings. However, a longer vase life would provide more flexibility for growers and florists.
Few commercially available postharvest floral treatments extend the vase life of dahlias. Commercial hydrating solutions are used for short periods of time of 1 d or less to improve water uptake in stems. They improve the vase life of some cut flower species, but they do not have an impact on dahlia vase life (Clark et al. 2010). Holding solutions, which contain carbohydrates, acidifying agents, and germicides, reduce microbial growth and extend the life of dahlias in some cases, but not others (Clark et al. 2010; Dole et al. 2009). Benzyladenine and gibberellic acid are applied to dahlias as a pulse, which, typically, is a concentrated solution in which flowers are soaked for a short period of time (e.g., approximately 24 h). Although these plant growth regulators can extend the vase life of dahlias, they are not as versatile or commonly used as commercially available floral preservatives (Bergmann et al. 2018). Other preservatives or approaches to extending vase life may be desirable.
Our primary objective was to grow and evaluate a variety of dahlia cultivars in the northeastern United States (United States Department of Agriculture Hardiness Zone 5a). We compared cultivars to determine whether the flower timing, yield, and quality differ. Our second objective was to determine whether two commonly available commercial holding solutions extend the vase life of dahlia. We compared the vase life of three cultivars stored in holding solutions intended for flower storage and transport.
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