Enhancing blue hydrangea sepal coloration by applying aluminum sulfate through constant liquid fertilization
The vibrant color produced on hydrangea (Hydrangea macrophylla) sepals make it a significant crop to the US greenhouse industry. When aluminum (Al) is supplied blue sepals are produced as the Al binds an anthocyanin, while pink sepals are formed when no Al is supplied. The typical production practice used to induce blue sepals is by applying Al2(SO4)3 (AlS) via several substrate drenches. The drench application process can be time consuming and labor intensive for growers and there are no recommended doses for Al applied through a constant liquid fertilization. This study determined the effect of applying AlS in constant liquid fertilization on sepal color and substrate leachate pH and EC for 4 hydrangea cultivars. The 4 hydrangea cultivars were treated with a total dose of 0, 9, 12, or 15 g of AlS per plant. The results of this study found that applying AlS through a constant liquid fertilization increased blue sepal colorations in all 4 cultivars while pH and EC levels were within acceptable parameters.
Landis, H., Hicks, K., McCall, I., Henry, J.B. and Whipker, B.E. (2021). Enhancing blue hydrangea sepal coloration by applying aluminum sulfate through constant liquid fertilization. Acta Hortic. 1305, 455-462
anthocyanin, delphinidin-3-glucoside, fertility, plant nutrition, Hydrangea macrophylla