diff --git a/var/spack/repos/builtin/packages/arbor/package.py b/var/spack/repos/builtin/packages/arbor/package.py
index d1c372284a..9adacf477f 100644
--- a/var/spack/repos/builtin/packages/arbor/package.py
+++ b/var/spack/repos/builtin/packages/arbor/package.py
@@ -70,4 +70,7 @@ def cmake_args(self):
         if '+cuda' in self.spec:
             args.append('-DARB_GPU=cuda')
 
+        # rely on spack's compiler wrapper to set architecture
+        args.append('-DARB_ARCH=')
+
         return args