Hi Clarissa, thanks for posting this idea! This topic is definitely important and extremely overlooked in most educational systems from what I know. I agree that it would be important to include plant knowledge in the study curriculum in order to complement the student education.
However, I think that one of the main limitations to educate on plants is the fact that there are an insane amount of different plants, and they don't always have very characteristic traits to differentiate them or singularize them. If you think about how children study animals, there is always a "spectacle" component in seeing their distinctive physical characteristics, their behaviour, even their sounds. That makes children clearly differentiate the different animals and learn stuff about them.
Unluckily, plants are "less interesting" in this regard. Mostly because they don't move or make sounds, which makes them more "boring".
However, I believe that children should be taught about the local flora in their area the same way we teach them about animals. With this I mean that we should teach them the most distinctive traits (color, flowers, size) and also what makes them special, in the sense of whether they are poisonous, they are used for medicine or food, what other properties they have, etc. Trying to associate each plant with 1-2 specific traits would help better recognize and remember them. Maybe kids could have a favorite plant as well, not only a favorite animal!
The sense of doing that with the local flora is that kids could then be able to identify what they have around them and care about their environment. Obviously, this could be extended to other plants around the world, since there probably will be more interesting plants to talk about. But I believe starting with the local flora would be ideal.