B. don mistakenly planted two new flowering trees on bob's property. bob knew that don was planting

B. Don mistakenly planted two new flowering trees on Bob's property. Bob knew that Don was planting the trees, but didn't inform him. Is Bob obligated to pay Don for the value of the trees? If so, under what theory would Bob be obligated to pay Don, and how would the amount due be calculated?

I once worked on a case where a roofing company went to the wrong address and put a new roof on the house. The occupant was renting and assumed the landlord had placed the order. The judge ruled that the owner didn't have to pay anything and the roofing company could not remove the new roof because they couldn't fix the old one back like it was.

If Bob admitted that he silently watched the planting, well aware they were on his property then filed a lawsuit, he would be hard put to explain any damages since he didn't voice any objection. But since they were on his property, he could remove them. I don't see any situation where Bob would owe for the trees. Bob isn't required to supervise his neighbor's gardening any more than a landlord has a duty to guard his property to make sure local roofers hit the right house.