Swift Tower Willow is the best fast growing willow for narrow spots. Crown spread width of this quick growing tree can be as little as 8' in diameter. The quick growth can be used for privacy fences and shelterbelts on smaller lots. The shape of these fast growing trees are columnar.
Early indications suggest that this may be one of my fastest growing trees I am growing in Iowa. This is my rarest tree currently available for sale, so try a few before they are sold out!