Oak Leaf Galls in Scotland: Harmless Wasp-Induced Growths

Red/Pink Bumps = Gall Wasps

The little lumps on your 10-year-old oak leaves in Northeast Scotland are galls caused by tiny gall wasps (Cynipidae). The wasp lays an egg; the leaf forms a protective chamber.

No Harm, No Treatment

• Galls don’t affect tree health.
• May cause early leaf drop, but the tree refoliates.
• Control is impractical (timing must match wasp emergence, not gall visibility).

Your farmer neighbor can ignore them—they’re a cosmetic curiosity on young oaks.