It's near impossible to build a perfect composition, but so long as you can get Zyra and Annie with 3/6 Mages, you can summon 2 Tibbers and an infinite amount of Zyra plants.
If you manage to get 3 summoners as well, you will have huge duration and tanky as hell Tibbers.
It requires you to lose the early game and gain at least 4 Tears as the priority.
Secondary priority is Spatulas to make the mages.
The mage for Thresh is if dragon drops it or you get it from the carousal.
The idea is to keep Zyra in the middle of the backline where she will be able to ULT every 2 seconds.
She will constantly spam two times which instantly refuels her Mana to do it again.
While all of this is going on they get an increase of 80% damage because of Inferno so there is around 12 plants targeting everything in sight.
Tibbers runs interference, everyone else is running support an CC to keep her rolling.
There is pretty much no counter-play to this, Poison, Glacial, Berserkers. They all melt in seconds.
Remember, this is an extremely strong build.
But it is EXTREMELY hard to pull off as it requires good rolls early but you need to lose to acquire at the very least ONE Spatula and ONE Tear for Mage priority: ZYRA.
You could replace Taliyah with Veigar but really it's better for the interference to use her and easy ti +3 since nobody likes running her.