diff --git a/tools/plotting/histogram2.xml b/tools/plotting/histogram2.xml
index 91c8a9f6088..5ce3c259b41 100644
--- a/tools/plotting/histogram2.xml
+++ b/tools/plotting/histogram2.xml
@@ -27,6 +27,7 @@
   </tests>
   <requirements>
     <requirement type="python-module">rpy</requirement>
+    <requirement type="package">R</requirement>
   </requirements>
   <help>