Green Pillar Pin Oak Quercus palustris 'Pringreen' or 'Green Pillar' In our never ending need for trees with limited maturing forms, another is finding its way in the market. Consider the Green Pillar Pin Oak. Quite different from the straight species, which is incredibly wide, the Green Pillar is well named for its very narrow form. The branch structure is immediately ascending, straight up, and as tight and dense as you can imagine without corrective pruning. Anyone with experience pruning a regular pin oak can visualize the density of limbs in a columnar Pin Oak.
I suspect the ultimate height is considerable, probably well over 45’ in optimum soil and growing conditions. If like most columnar trees, it widens out over time, it would probably reach 15’, but probably only in late maturity. Occasionally we observe what I refer to as a ‘Lazy lateral’. This is when a lateral limb, because of excessive growth and weight will droop out of the columnar crown, hanging to the side. This is mostly seen in youth, under perfect growing conditions. Once reduced in weight and length, they will stiffen up and usually not re-occur.
The Green Pillar Pin Oak appears to be another excellent tough disease resistant variety for limited width locations. The leaves are typical pin oak shape and size, with fall red colors sometimes more spectacular than others in the Pacific Northwest. I suspect the fall colors are more reliable in our colder regions of the Chapter. Some may feel that the brown leaf retention through the winter is a drawback, but consider it a modest windbreak.
In the nursery, we find that this cultivar transplants as well as the species. Oak roots are typically deep unless limited by hardpan or compacted subgrade. The species is considered a lowland or flood plain species, so the Green Pillar should tolerate wet, as well as dry, conditions once established. Expect to see these on future street tree lists.