Mechanic concept for Zyra
I play a lot of Zyra and while she does have a lot of power, she often very restricted due to her seed management mechanics. Her strength lies in her ability to let her seeds passively spawn in an area, which can be difficult when you're in a game where fights/skrimishes break out in places you haven't been able to 'ready' and often times in teamfights, you're basically left to just spawn your plants, use your ult and hope for the best.
I don't necessarily believe Zyra needs the ability to spawn more seeds, since when she does get a good spawn on them, she can be very powerful and deal a lot of damage. I do believe that part of the problem with her mechanics are the random/limited spawning of her seeds being gated by her rotations and CDs.
I would say maybe adjusting the dmg of her spawns, increase their duration and allow for a new mechanic/passive where her abilities leave behind a sort of 'tilled soil' where even after she casts an ability, she can spawn her plants on the area for a couple seconds afterwards. I believe this would help Zyra be a bit more useful in teamfights, where she can more freely cast her abilities, and also use her seeds rather than having to wait for the CD of both her seeds and her abilities in order for her to really be effective.