Iris, Fleur de lis:
Recommendations for Maintaining Postharvest Quality
Produce Facts in English > Iris
Michael S. Reid
Department of Plant Sciences, University of California, Davis
Iris cvs. hybrids Because of their intense yellow, blue, and purple colors, and the elegant shape of their flowers and foliage, bulbous (Dutch) Iris are in considerable demand as cut flowers. Unfortunately, they are also one of the shortest-lived of the commercial cut flowers, and may not even open if handled improperly or held too long before sale. In recent years, other iris species, especially the ‘flag’ or German iris, which have even shorter vase life, have also been used in the trade. Iris is Greek for ‘rainbow’ in reference to the range of flower colors.
Iris grown at low temperature should be harvested more open than those grown in warmer conditions. Iris flowers are normally harvested at the "pencil stage", when a line of color projects out of the sheathing leaves. The 'Blue Ribbon' cultivar should be harvested more mature, when the edge of one petal is unfurled. Iris is pulled from the field at the correct stage of maturity. The bulb is cut off and the lower foliage removed. The flower stems are then placed in water. Wholesale and retail florists should purchase iris in the pencil stage. This term describes flowers that exhibit a line of color vertically, as the sheathing leaves covering them unfurls, but before the flower petals reflex. A major exception is the cultivar ‘Blue Ribbon,’ which should be more open at the time of purchase.
Grading and Bunching
There are no formal grade standards for iris flowers. Flowers should be uniform in variety, color, and maturity. Foliage should be relatively undamaged and free from disease. Stems should be strong and straight. Flowers are normally bunched in 10s, then the bunches are tied with rubber bands or twist-ems.
Iris is not affected by exposure to ethylene.
There are no recommended pretreatments for iris flowers.
Store iris dry, upright, at 0°C for no more than one week. Some growers store iris with the bulb attached. Prolonged storage may result in failure of flowers to open (especially the 'Blue Ribbon' cultivar). Storage at warmer temperatures will result in ‘popping’ of the flower when it is rehydrated.
Iris is normally packed in upright hampers.
Researchers have obtained some increase in the vase life of iris by including a high concentration of benzyladenine in the vase solution, and pretreatments with gibberellins have been shown to overcome the negative effects of dry storage.
First published on this website: October 2004