> I do know that I want to encourage him to think about relationships between things, rather than just learning a list of names. (For example; "That tree is evergreen, which means it keeps its leaves all year round. It does that because [...]" rather than "That's a Leylandii".

I don't suppose there's any harm in loading your children up with trivial knowledge, but I would certainly put more effort into teaching them thinking skills than specific knowledge.

These days, if you have the necessary thinking skills, the sum of human knowledge is within reaching distance. If you know how to research a subject, how to corroborate and verify the veracity of positive claims and theories presented to you, you can find out pretty much everything about anything in a matter of minutes.

I suppose it's the old "give a man a fish" adage applied to knowledge.