Zoe Schlanger - The Light Eaters. Buy this yesterday. It's so fucking good. All the current science on plant communication and neurology. The Factually podcast did a good interview with the author recently- https://www.youtube.com/watch?v=eBToVPeuHX0
Michael Pollan - The Botany of Desire. Pollan is better known for his How to Change Your Mind book about psychedelics, but this a particularly good book on four materialist histories of plants.
Matt Candeias - In Defense of Plants. It's kind of like a broader version of The Light Eaters with a focus on plant behaviour.
Richard Lewontin - The Dialectical Biologist. This and Biology as Ideology did more for me as a scientific horticulturist than any particular book about plants. To understand a plant, you need to understand the dialectic of organism and environment because a plant is intrinsically tied to one setting it mediates its whole existence around. The biggest thing that will hinder you in plant science is the way it isolates the subject into an object of study, trying to remove as many of the variables as possible. But plants exist as a product of endless variables and The Light Eaters shows that we've barely scratched the surface of their world or how it works. The more nuance you can build into how you approach plants- the ecology, the chemistry, the soil-atmospheric interfaces, the ethnobotany and anthropology, the environmentalist theory- the better you'll understand them. Botany on its own is pretty narrow.
[ultra-wealthy movie man endorses genocide against starving children] 
it'd be a real shame if we turned loose all these Nazi serial killers who know how to bomb people with cheap robots
Nature is the proof of dialectics. It's easy to visualise the dialectic between a bee and a flower, with both of their lifecycles intrinsically dependent on the other and their material/social role. The bee exists through its metabolism, collecting pollen/nectar and supplying them to its complex hive society for use as honey. Its body evolved sacs to carry even more of it. If a flower can't self-pollinate, it has evolved to attract pollinators. It will draw from its dialectical relationship to sky/soil and synthesise new chemicals, it will evolve its body to look like the female version of a particular wasp so the males try to mate with it, it will find new ways of attaching more pollen to each bee. As long as the material conditions exist for the flower and the bee, their metabolic interaction with them will sustain and develop their dialectic with each other and their individual lives as a result of it. Take away the flower and the bee no longer exists, take away the bee and the flower no longer exists. They are structurally interdependent and no individual bee can decide to take up farming or accounting instead because the material conditions don't allow for that.
There's also climate change, the organs of the human body, predators and prey, rocks and rain forming waterways over time, and the good ole Heraclitus' "No man steps in the same river twice, for he is not the same man and it is not the same river." with a breakdown of all the ways those two things have changed as a result of their other dialectics in-between swimming sessions.