Q: My neighbor has a fence separating our lawns. He comes over to our side of his fence and mows 10 feet into our lawn.

A: Adverse possession can be remembered reasonably accurately with the acronym POACH. To achieve adverse possession, the bar against landowners pleading to protect their property, the adverse possessor must POSSESS OPENLY ADVERSELY CONTINUOUSLY and HOSTILELY for the requisite number of years. I see nothing hostile about his offer to mow your lawn unless he is aggressive or demanding about it. Indeed, if you simply thank him for his neighborliness, it won't be adverse, though I do wonder about the provability of that 21 years from now, provided he keeps mowing your lawn for that long. It isn't even clear how mowing a lawn can be possessing it. Perhaps if he was hunting on it. I did once win a case based on the evidence that my client's great great grandfather hunted eagles on the property. In short, you have no real worry, but if you are still worried, you can:

• notify him not to trespass, but this is not only unneighborly and unnecessary, but it will now make his continued mowing hostile and adverse, and you will need to enforce your demand;

• write him a letter inviting him and thanking him for mowing your lawn, though you need to make sure that the owner of the property 20 years in the future knows ion this letter, and it seems unduly expensive to record it in the land records;

• build a flower garden, gravel, flagstone or other border on your land so your grass doesn't get on his fence.