I appreciated your postharvest information for roses. Please help me with some information about packing for freight transport and control of bruises on soft petal varieties of rose. (B.M.)
Thanks for the request for information on controlling bruises during transport of roses. As you are aware, the petals of roses are very delicate, and subject to compression bruising. This bruising is more obvious in the light-colored cultivars (whites, pinks, pale yellows), because the browning that results is more clearly seen, but it certainly occurs in all cultivars. Our standard recommendations for packing roses (and other flowers) are to pack gently, but securely (to avoid vibration bruising) and to avoid over-packing. Unfortunately, over-packing is an inevitable result of the high cost of air freight, and the volumetric basis on which this cost is determined. I frequently see cartons of roses that are almost round from the extra flowers that have been forced into them to reduce the per-stem cost of air freight. Flowers in such boxes cannot be pre-cooled efficiently, and will inevitably show a high level of bruising. In one large production center I saw grown men using strapping equipment to squeeze roses into a box half the size that should have been used. Of course all the flowers will be bruised after such treatment, and no cushioning or wrapping materials will prevent it.
Experiments in which roses were harvested, cooled, and packed without ever being placed in water resulted in dramatic reduction in bruising, and (for some cultivars) even an extension in vase life. "Rehydration", particularly at temperatures above 0 C (32F), results in continued growth of the rose bud, so that there is more volume to be packed in a box for a given number of buds. So that's an option that's worth exploring.
Obviously these are general comments that may or may not relate to your operation - if you have specific questions I'd be glad to answer them.