ts = Series(np.random.uniform(size=10), index=date_range('1/1/2000',
    periods=10))
ts = ts.cumsum()
ts2 = ts[markers]
fig, ax1 = plt.subplots()
ax1.plot(ts.index, ts, 'b-')
ax1.plot(ts2.index, ts2, 'g^')
fig.autofmt_xdate()
how to plot arbitrary markers on a pandas data series?