Behind the row houses of Union City there is a green nobody sees from the street — narrow back yards fenced one after another, each holding its own private June. YIYILANDSCAPING works those hidden squares, mowing where a mower barely turns, trimming along fence posts and concrete edges, carrying the clippings out the same way they came in. Where the land tips down toward Weehawken the yards step into terraces and the grass grows uneven, which simply means more hand work and more patience. Hedges get shaped, beds get mulched, and the heavy clearing happens once in spring and once when the leaves come down. The payoff is a back yard cut clean and open — room enough for a table, a grill and a Saturday.