You can get a money tree using the golden shovel.
If you want to a huge landscaping of regular tree you can plant 1K and get a regular tree.
This comes in handy if you want all pink trees for April.
my impression has been that the fertilizer guarantees you will grow something in the spot you bury it; it's just that if you are trying to cross-breed to create a new hybrid there's no guarantee that's what you will get, although it allegedly increases the chances of growing a new kind of cross-bred hybrid.