Yeah, that would be nigh on impossible.
You'll need to either:
- give a huge wad of cash to the chaps in charge of making dictionaries.
- give a huge wad of cash to the chaps in software development (at several different companies), or
- generate a virus that will add the word to users computers.
The only "feasible" option that I can think of is to get it into very widespread use in the U.S. - sort of like you can find the word "Oprah" in the dictionary, but not the word "Uluru" (though that one will show up in an encyclopedia).
The problem is that "Langtrees" is a name, not a word that describes something else. You'd need to get the name diluted as a brand. Like how "Nike" is not in the dictionary because it's the name of a company but "Band aid" is because people use band aid to describe generic adhesive bandages rather than adhesive bandages made by the Band-Aid(TM) Company.