To achieve a long vase life, removing the thorns is not recommended. Every wound on the stem leads to deterioration of the stem bark and the loss of cell moisture, resulting in major container/vase contamination. This results in wilted leaves, very little or no flower development and turbid, smelly containers and vases. With Rosa it can even lead to the manifestation of bent-neck.
VASE LIFE TESTS
Roses with thorns last longer in the vase than roses without thorns. When flower food is added to the vase water, the differences disappear. However, the vase water of roses without thorns does remain turbid.
VASE LIFE KILLERS
The only excuse for removing thorns is to make arranging easier and protect the hands if no gloves are used. If you have to, remove the thorns with as little damage to the tissue as possible. The consumer can best remove them by breaking them off by hand, pushing them aside. All other methods of using knives and thorn removers are harmful to the flower.