Buff Zyra
Please, actually read this before you go straight to the comments and complain about her being "op" and needing nerfs instead.
I know so many ADCs out there complain about her, saying she's just as bad as Brand support, but trust me, the only thing Zyra has over him is more CC. She's a combination of to squishy, can't combo, and not enough damage, all of which why she's played primarily support. During the 6.9 update she got the same treatment as Brand and was essentially nerfed into support. Sure she got a great new passive that allows her to summon up to like 8 plants, but more plants doesn't always mean more damage.
Something most people don't know or realize is that for each new plant she summons it only does 50% amount of the damage as the previous one, meaning she would need all 8 plants up to do the total damage of just 4 plants. Along with the new passive came the nerfs to her regular abilities, both her Q and E getting nerfs to their AP ratios. What was worse is that they changed the passive on her W, where instead of giving CDR it now just gives more health to plants for each point you put into it. With Zyra already having a very low CDR build you took away one of her very few sources of CDR.
Lets just make this simple and compare Zyra to Lux, who's also a mid laner/support but unlike Zyra can actually go mid and probably win. While yes both of them do significant damage, Lux can actually keep a target still long enough to dish out all the damage. With Zyra, her only CC outside of her ultimate is her E and her melee plants slows, with her E only rooting for .75 second at rank one and 1.75 second(s) at rank 5. Another reason Zyra cant really go mid is that% it's stuck between the choice of maxing her E first for a very small root or max her Q for quick burst damage, unfortunately neither decision is really a good decision with her Q having a short range and the weirdest hitbox making it incredibly easy to avoid unless you land your E first. Now with her ultimate, it takes 2 wholes second before it knocks up, which is really way to long, and has an incredibly short range making Zyra have to stay a little to close for comfort towards the enemies, which brings us to her next problem: her squishiness.
Lux is way squishier than Zyra, but what Lux has is her W, her shield, and incredible range, with Zyra having neither of those. Like I said above, Zyra has to get far to close to comfort to use her abilities, and because of this she tends to lose a lot of health which makes it difficult for her since she lacks sustain. Even compared to other supports Zyra isn't the best choice, with other damage supports having sustain, Morgana has her spell vamp from her passive, and Karma has her empowered W.
What Zyra really just needs is longer range on her Q and R, desperately on her R, raising the damage on her Q, not a lot just a little by increasing the base damage overall by 10 or 15 points per level, and increasing the root time on her E from .75 to a whole second at base rank and ending at 2 seconds at final rank. I understand that's it's an AoE root which is why it has such a short timer but I think most Zyra players would be willing to sacrifice that, by instead of rooting everybody, it would just root the first 3 enemies hit. She also needs a way better passive on her W and an increase to her base health. And again, on her R, the wait before it knocks up is just way to long, just lower it from 2 seconds to 1.5 seconds. I would be just fine if instead of any actual damage buffs, they just increased the range on her Q and R and increased the root time on her E.