having trouble with the new "Maokai support" fad?

Marksmen: Take Warlords Bloodlust

Supports: Play something with sustain and good gank-assistance. Or shields + gank assist if you're good at managing damage intake around shield timings.

When Maokai spams his spalings into brush, lure them into your minion wave and then get clear, this will auto push your lane under tower. While this will lead to chip damage on your turret it ALSO puts your AD in a safe place to farm, as non-brush saplings are significantly weaker. Warlords + support healing will ensure you don't get forced out of lane, and being pushed under tower means that Maokai is over-extended and easy to gank. If he's a dumbass and building AP he probably wont have heavily invested in vision, easy double kill for your jungler.

Even if he doesn't build AP, sapling spam will deplete his mana, making him relatively useless when your jungler comes in.

Don't fight him, endure him, also when the gank comes in go for his ADC first, a support Maokai doesn't have the damage to kill your carry on his own, and when he dives in with W he leaves his ADC defenseless. You're welcome.