diff --git a/holoviews/plotting/mpl/chart.py b/holoviews/plotting/mpl/chart.py
index 46c547434f..aad85b89de 100644
--- a/holoviews/plotting/mpl/chart.py
+++ b/holoviews/plotting/mpl/chart.py
@@ -621,7 +621,7 @@ def get_data(self, element, ranges, style):
         xs = element.dimension_values(xidx) if len(element.data) else []
         ys = element.dimension_values(yidx) if len(element.data) else []
         radians = element.dimension_values(2) if len(element.data) else []
-        if self.invert_axes: radians = radians+np.pi/2.
+        if self.invert_axes: radians = radians+1.5*np.pi
         angles = list(np.rad2deg(radians)) 
         if self.rescale_lengths:
             input_scale = input_scale / self._min_dist