The Gift Tree is a new plant introduced in the Ratboy's Nightmare update which is the most expensive gardening item- separate from the salamander eggs. It can be obtained, as of players are aware, only from Mr. Sims- who can be found directly outside Topple Town.
The gift tree seed can be purchased at random from Mr Sims between 1.9 million and 2.1 million coins. It always appears in the third slot:
At the current time, we do not know how much the gift fruit sells for or what it does.