Suggestion for a new Zyra passive

I'm not here to argue about why or if she needs a new passive I just want to suggest one if it were to happen.

Scaling Is estimated

New passive, Spores: Zyras abilities, Thorn Spitters and Vine lashers apply a debuff on enemies hit that lasts 5 seconds and stacks up to 5 times. Zyras basic attacks against those targets consume all stacks dealing 8/16/24/32/40(give or take) true damage per stack at levels 1/6/11/16/18.

Clearly this would mean she has more damage potential without dieing but it is limited to her basic attack range and requires landing skillshots to apply so it's basically reward for risk/skill, but if necessary I'd suggest very small nerfs to her other damaging abilities i.e. 5% less ap scaling on q-e-r.

Considering zyra's weakness is being an immobile squishy, a small buff to her health and or movement speed would be a reasonable compensation for losing an after-death ability, and help her manage the new passive mechanic.

Note* This debuff would be able to affect multiple targets at once and has no cooldown on re-application.