for c, z in zip(['r', 'g', 'b', 'y'], [30, 20, 10, 0]):
    xs = np.array(some_dates)
ys = np.random.rand(20)
ax.bar(xs, ys, zs=z, zdir='y', color=c, alpha=0.8, width=8)
ax.w_xaxis.set_major_locator(ticker.FixedLocator(some_dates))
ax.w_xaxis.set_major_formatter(ticker.FuncFormatter(format_date))
for tl in ax.w_xaxis.get_ticklabels():
    tl.set_ha('right')
tl.set_rotation(30)
ax.set_ylabel('Series')
ax.set_zlabel('Amount')
plt.show()
Matplotlib: Formatting dates on the x-axis in a 3D Bar graph