Easily add vertical line to pandas plot.bar() time series data

Question

I was trying to do something simple: plot some bar plots and add a vertical line, for a dataframe like this:

  index         data
2021-06-05    14628.0
2021-06-06     1969.0
2021-06-07    50918.0

And doing this:

 df.data.plot.bar()
 plt.axvline('20210606')

To my surprise, this only works on df[col].plot() but not on df[col].plot.bar(). I tried figuring it out and I found I could manage to plot my line by finding what x data matplotlib's actually getting:

ax = plt.gca()
rectangles = ax.patches
plt.axvline((rectangles[1].get_x() + rectangles[1].get_width()/2), color='r')  

Which brings the desired plot, but in a very non-straightforward way. Is there any way to achieve this by actually using dates or should I get used to ax.patches ?

Thanks !