(78) Sheltering Cut Flower Plants to Increase Stem Length

Abstract

The stems of many flower species used as cut flowers are too short to be commercially useful. Non-chemical techniques are needed to increase the length of the harvested stems without weakening stem strength. Field experiments were conducted that explored the use of black or red shade fabric, used either as a canopy, or as a side curtain, with three species of cut flowers. Trachelium caerulum, Eustoma grandiflorum (Echo Champagne), and Rudbeckia hirta (Prairie Sun) were grown in split-plot experiments in which shade and shelter treatments were applied as main plots, and the flower species formed the subplots. In 2004, shade canopies of 70% light transmission were compared in black and red (“ChromatiNet”) netting, and 50% red netting. Stem length increased from 51 cm for unshaded controls to 54, 56, and 59 cm for 70% black, red, and 50% red, respectively. Productivity of the plants was decreased an average of 21% by shading. In 2005, shade canopies of 50% black or red were compared to side curtains of the same materials, and an unsheltered control, growing the same species of flowers. Stem length was increased by 25% when plants were grown under a shade canopy, and by 14% in the side curtain plots. Shading treatments reduced stem yield by 31%, whereas side curtains had no significant effect on number of stems per plant. Color of the netting did not affect stem length or stem yield in 2005. In both years, the thickness of harvested stems were increased significantly in the shelter treatments. The three species reacted similarly to the treatments imposed in both years. Shelter treatments can be a practical way of increasing cut flower stem length.