Wildflowers Found in Oregon

Spiny Rose Gall

Rose galls occur on leaves or stems of the rose plant and are specific to the species of gall maker. The spiny rose gall is round with many pink spines. Insect larvae develop inside the gall. Stem galls can damage plants above the location of the gall, especially if there are many galls on a particular stem. Numerous galls may stress the plant because nutrients otherwise available for plant growth are used to produce galls. The spiny rose gall is caused by tiny cynipid wasps. They produce small hard internal caverns armed with stout, sharp spines on the exterior. The galls usually occur on the surface of leaves, but they sometimes occur on stems. These rose galls do not appear to harm the plant. Spiny rose gall develops exclusively on wild roses.