title: plot.area() isnt showing in pandas
body: <p>I have a dataframe named <code>df1</code> where I have columns <code>col_names = ['issuedate','channel','coupons','revenue']</code>, and df is looking something like that:</p>
  <pre><code>   issuedate    channel     coupons     revenue
   0  2009-01-01  WWW        9999999     103082.98
   1  2010-01-01  Агенты     5           16518.01
   2  2010-01-01  КЦ         1           1137.22
   3  2010-01-01  С7 Билет   12          55239.87
   4  2010-01-01  ТКП        3           16800.00
  </code></pre>
  <p>After, I try to plot counts of <code>channel</code>s in <code>issuedate</code> (channel_old is channel, that's not a point :)):</p>
  <pre><code>data7 = {     &quot;BSP/ARC&quot; : df1.loc[(df1['issuedate'] &gt;= '01/01/2010') &amp; (df1['issuedate'] &lt;= '01/01/2012') &amp; (df1['channel_old'] == 'BSP/ARC') ]['issuedate'],
  
                &quot;WWW&quot;:df1.loc[(df1['issuedate'] &gt;= '01/01/2010') &amp; (df1['issuedate'] &lt;= '01/01/2012') &amp; (df1['channel_old'] == 'WWW') ]['issuedate'],
  
                &quot;Агенты&quot;:df1.loc[(df1['issuedate'] &gt;= '01/01/2010') &amp; (df1['issuedate'] &lt;= '01/01/2012') &amp; (df1['channel_old'] == 'Агенты') ]['issuedate'],
  
                &quot;КЦ&quot;:df1.loc[(df1['issuedate'] &gt;= '01/01/2010') &amp; (df1['issuedate'] &lt;= '01/01/2012') &amp; (df1['channel_old'] == 'КЦ') ]['issuedate'],
  
                &quot;Предст&quot;:df1.loc[(df1['issuedate'] &gt;= '01/01/2010') &amp; (df1['issuedate'] &lt;= '01/01/2012') &amp; (df1['channel_old'] == 'Предст') ]['issuedate'],
                
                &quot;С7 Билет&quot;:df1.loc[(df1['issuedate'] &gt;= '01/01/2010') &amp; (df1['issuedate'] &lt;= '01/01/2012') &amp; (df1['channel_old'] == 'С7 Билет') ]['issuedate'],
              
                 &quot;ТКП&quot;:df1.loc[(df1['issuedate'] &gt;= '01/01/2010') &amp; (df1['issuedate'] &lt;= '01/01/2012') &amp; (df1['channel_old'] == 'ТКП') ]['issuedate'],
  
               };
  dataFrame = pd.DataFrame(data=data7, columns = [&quot;BSP/ARC&quot;,&quot;WWW&quot;,&quot;Агенты&quot;,&quot;КЦ&quot;,&quot;Предст&quot;,&quot;С7&quot;,&quot;Билет&quot;,&quot;ТКП&quot;], index = pd.date_range(start='01/01/2010', end='01/01/2012', freq='M'))
  dataFrame.plot.area(stacked=True);
  </code></pre>
  <p>So as a result I have a empty plot, that is wrong:</p>
  <p><a href="https://i.stack.imgur.com/ke6Vi.png" rel="nofollow noreferrer">enter image description here</a></p>
  <p>Whereas command like:</p>
  <pre><code>df1.loc[(df1['issuedate'] &gt;= '01/01/2010') &amp; (df1['issuedate'] &lt;= '01/01/2012') &amp; (df1['channel_old'] == 'С7 Билет') ]['issuedate']
  </code></pre>
  <p>works as right, and gives:</p>
  <pre><code>3      2010-01-01
  9      2010-01-02
  15     2010-01-03
  21     2010-01-04
  27     2010-01-05
            ...    
  4765   2011-12-27
  4772   2011-12-28
  4779   2011-12-29
  4786   2011-12-30
  4792   2011-12-31
  Name: issuedate, Length: 729, dtype: datetime64[ns]
  </code></pre>