Hello and props for this nice little guide you got there :)
Some small suggestions if i may, you could add a ''Why pick Maokai'' section explaining the strengths of Maokai in the support role and what he can provide for the team! This would sparkle the reader's interest to play Maokai as he could see some hidden potential with that description!
Also, maybe you could put some more descriptions covering other really viable supportive items, such as Knight's Vow or Locket of the Iron Solari and Zeke's Convergence, as they can be really helpful to keep your carries alive as a Tanky Support, so explaining when and where to pick them up in detail should really be helpful! :)
Anyways, sorry for the long post and great job!