title: discard x-axis label in multi-bar chart in matplotlib
body: <p>I have produced the graph shown below as intended with matplotlib and Pandas except two problems:
  I can't get rid of the x axes labels (Year) for the three plots at the top (things I have tried are commented out in the code attached), and I could not centre the y axis label. 
  It seem trivial but I can't get it to work.
  Any suggestions?
  Thanks</p>
  
  <pre><code>fig, axes = plt.subplots(nrows=4, ncols=1, sharex=True, figsize=(12, 12))
  for i, crop in enumerate(['Cabbage','Green beans','Potato', 'Wheat']):
      mean_irr_soil[crop].plot(kind='bar', ax=axes[i], title=crop, grid=False)
      axes[i].set_ylim([0, 700])                  # set limit for all y axes
      axes[i].tick_params(axis='x', top='off')    # remove top ticks
      axes[i].tick_params(axis='y', right='off')  # remove right-hand ticks
      axes[i].tick_params(axis='x', labelbottom='off')
      if i is not 0:
          axes[i].legend_.remove()    # all but top graph
      # if i is not 3:
      #     axes[i].get_xaxis().set_visible(False)      # remove axis all together
          # axes[i].tick_params(axis='x', labelbottom='off')
          # axes[i].set_xticklabels([]) # remove x-axis labels
  axes[0].legend(bbox_to_anchor=(1.1, 1.4))
  axes[2].set_ylabel('Mean irrigation requirements in mm')
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/Xm5ud.png" alt="enter image description here"></p>