I’ve heard that one can acquire title to land by “possessing” it, so long as the true owner of the land doesn’t object. There’s no dividing line between my yard and my neighbor’s yard. His property is technically much bigger than mine. About a decade ago, I decided to make a little investment by planting a small tree in a portion of his yard. I water it every now and then, usually sneaking onto his land at night, but have mostly let it grow on its own. Now, ten years later, my neighbor has never said anything. I don’t think he or anyone else even realize that I planted it. Will I be successful in a claim for a portion of his property?
Someone who plants a tree by cover of night is unlikely to succeed on acquiring title to a neighbor’s property using the legal doctrine known as "adverse possession." Even assuming that your ten years of “possession” meets the statutory requirement, you appear to be missing a crucial element of adverse possession: a trespasser’s conduct must, among other requirements, be “open and notorious.”
This means that the trespasser must use the land in question in a manner similar to that of a typical owner. While there’s no requirement that the true owner has actual knowledge of the trespasser’s presence, the trespasser cannot occupy the land in a secretive way, or intentionally try to remain undetected. The idea is that the trespasser should spend that statutory period acting as if he owns the land, making his possession clear to the true owner or anyone else.
In the situation you describe, you purposely planted a small tree on your neighbor’s land, and have been quietly waiting for the statutory period to expire. You enter your neighbor's land occasionally, and only at night when he would be unlikely to see you.
A court might very well view this tactic as nothing more than sneaky – an intentional effort to broaden the title of your land. It is unlikely that you’d be able to acquire title to a portion of your neighbor's land through adverse possession in this manner.