Residents have been planting the ornamental trees outside their houses and in lawns to add beauty and give their place a grand look.
Now usually I see sentences like "...have been doing this/that for 5 years..." or "....have been doing this/that since 1950..." etc. But this sentence does not have any such time span or point of time mentioned. Does that make it incorrect? It is clearly understandable this sentence in present perfect continuous tense means that the tree planting has been going on for some time.
I was told the correct form would be Residents have planted the ornamental trees outside their houses and in lawns to add beauty and give their place a grand look. This is correct as a sentence in present perfect tense.
But I'm not sure that the first form of the sentence is indeed incorrect. Or is it wrong for some other reason?