Expert: Lynnette Callan - 4/19/2007

Question
I am the president of the Maine Rose Society, and have been asked these questions by a teacher in OK City: Why do roses have thorns?  How have they developed roses without thorns?  Are roses more or less hardy with or without thorns?  This teacher's name is Suzanne Howse, email is kidzteacher@sbcglobal.net. Can you help her, I do not know the answers to her questions, except the last one, and I am pretty sure the health does not change if roses are thornless.  Thank you so much, Joan M. Gotlibson

Answer
Officially if you want to be considered very correct in your terminology then modified leaves are referred to as spines, modified branches are thorns and modified epidermal cells are prickles. In most cases, people simply refer to them as thorns or spines. Examples of a few plants that deploy these types of defenses include roses, raspberries and blackberries. Regardless of what we call them, structures such as thorns make it difficult for animals to come along and take a bite without a painful lesson. Before men started to cross roses, they used to grow like wild brambles along the ground and some grew like a large raspberry bush. No matter how they grew, the thorns served as protection. There are a few wild roses growing in the south, that have very few thorns naturally and these have been bred into modern roses to produce the thornless roses. This type have all the genetic makeup of a rose with thorns and so share all the attributes with them such as being hardy and healthy. Hope this helps.