diff --git a/src/kernel/region.c b/src/kernel/region.c
index 723c4c438..6b34957f1 100644
--- a/src/kernel/region.c
+++ b/src/kernel/region.c
@@ -1242,6 +1242,7 @@ void terraform_region(region * r, const terrain_type * terrain)
     assert(terrain);
 
     r->terrain = terrain;
+    reset_herbs(r);
     reset_rawmaterials(r);
     terraform_resources(r);