Its vs It's

Wow, maybe I should start a grammar column. This one is per Boni's request.

"Its" vs. "It's" can be confusing because most of the time, when we want to make something possessive, we add an apostrophe and an "s". If we want to say that the leaf belongs to the tree, we write, "It is the tree's leaf." So, we mistakenly believe that if we say "It is its leaf," there should be an apostrophe there on the "its." There isn't. "Its" is a possessive pronoun, just like "His" (which also ends in an "s" but doesn't need an apostrophe to indicated possessiveness.)

The word "it" only has an apostrophe when it's a contraction of "It is." (Did you notice I just used it).

So, the above sentence -- "It is the tree's leaf" -- could become "It's the tree's leaf," or "It is its leaf," or "It's its leaf."

Bottom line: If you can replace "its" with "it is," then use an apostrophe. If not, don't.