This view of part of a hedge row in a city park deserve some comment.

First, the rhus aromatica (fragrant sumac) shown here has an unusual (in my experience) growth habit. Two plants are shown. Both have adopted a tree-like rather than a shrub-like branching pattern. One is still upright, while the other has drooped or slumped toward the ground. Further along this same hedge row, just out of frame to the right, plants of R. aromatica with a much lower, shrubby profile can be found. I won't even speculate on what caused the different growth patterns.

Second, this hedge row is being taken over by the non-native and at least locally highly invasive common buckthorn. Left unchecked, it will eventually drive out almost every other type of shrubby plant, although it is possible that the tree-like R. aromatica specimens might stand a better chance of surviving than does the lower growing shrub form of it.