Is there a way to re-read previous Tree of Wisdom tips in-game?
Solution 1:
In the PC version of the game, you can leave the game on the Tree of Wisdom screen for a while without feeding the tree and the tree will repeat previous tips, albeit randomly. I would guess this works for the XBOX version. Previous tips always start off with:
Here's some wisdom that bears repeating...
If you're not concerned with spoiling tips you haven't unlocked yet, you can look at the full list of Tree of Wisdom tips on the Plants VS Zombies wikia.