Jarvan IV vs Zyra

Plant Demacian Standard (E), then cast Dragon Strike (Q) toward it: you fly to the flag and knock enemies in your path into the air.

Land an auto as soon as you reach your target: Martial Cadence (passive) adds damage based on their current health, then only triggers on them again after a few seconds.

Cast Cataclysm (R) on a carry who is away from their team: the arena is impassable, and you can recast to collapse it if it gets in your allies' way.

In teamfights, plant Demacian Standard (E) near the allies who are attacking: it gives them attack speed while they stay close to it.

Get out of the line of Grasping Roots (E): the roots pass through minions and root every enemy hit, then her plants hit the trapped target.

Step on her seeds to destroy them before she grows them: Rampant Growth (W) seeds reveal you for a moment, but leave her no plant.

Take down the plants born from Garden of Thorns (passive), or back off until they die: they take fixed damage, like a ward, and don't live long.

Get out of the Stranglethorns (R) zone as soon as it appears: the vines knock you into the air 2 seconds later, and her plants are empowered inside.

If you can engage, go for Zyra when her plants are far from her: the Thorn Spitter from Deadly Spines (Q) only fires at 575 range.