Sunday, November 27, 2011

Parking Lot Oaks

Plants that can live (and thrive) in adverse conditions like parking lots and roadway medians are special indeed.  Those that do so are prized by landscape designers and their use often is repeated.    These same trees might show up on lists of urban (also known as “street”) trees.  While maples are often used in these conditions, here are five oak trees that I have seen recently that fit this bill; four are native and one is exotic.

Nuttall oak (Quercus texana)
Pin oak (Quercus palustris)

Pin oak (Quercus palustris) has been a parking lot staple for many years around North Atlanta.  The trees planted some 30 years ago are now trees of considerable size – in places where they were allowed to remain.  Unfortunately in some urban areas, trees are considered expendable when it comes time to expand further.  Don’t let the common name fool you – the pin oak does not have slender “pin” shaped leaves.  The leaves are broad and usually have 5-7 lobes.  Q. palustris tends to retain it’s dried leaves over the winter, allowing for some measure of privacy when planted in a residential area.  That characteristic plus slightly drooping lower limbs are key identifiers for me.  The acorns are rather small and striped.  Like many urban tolerant trees, this species is naturally at home in poorly drained soils with high clay content.  I have never noticed this species having any remarkable fall color. 

Pin oak (Quercus palustris)


Willow oak (Quercus phellos) is another parking lot staple and continues to be used even in new developments.  Perhaps the narrow, linear leaves are more friendly to clean up crews in the fall than other oaks.  This is the tree that people think of when you mention “pin oak”.    The rapid growth rate and pleasing shape of the mature tree are probably two of the reasons it is still used in design.  Again the acorns are rather small (perhaps a plus for high traffic areas) and faintly striped.  Again this tree is naturally found in poorly drained areas, making it ideal for use in urban areas.  The fall color is yellow and rather unremarkable.  I found this example in a church parking lot along with the pin oak above.

Willow oak (Quercus phellos)


Shumard oak (Quercus shumardii) is a moderately fast growing tree with handsome lobed leaves.  It became popular as an alternative for the overused Pin oak some years ago.  The leaves of the two species are very similar in appearance but Shumard oak has better fall color and the dead leaves do not persist.  The acorns are much larger and resemble those of Northern red oak (Quercus rubra).   I found this example planted as a median tree along an office park throughway, but the trees were not doing very well.  My research shows that while this species can do well, it does prefer more moisture than others.

Shumard oak (Quercus shumardii)



Nuttall oak (formerly Quercus nuttallii or Quercus shumardii var. texana, now Quercus texana)  is perhaps the most recent favorite in parking lot design when it comes to choosing an oak.  This species is the best looking of the group: the leaves are handsome and lobed and have superb fall color.  Couple those looks with a fast growth rate and you have a winner as far as the landscape design folks are concerned.  The acorn is similar in looks to Shumard oak, except smaller in size and with a “goblet” shaped cap.   I found this example in a supermarket parking lot where the acorns on the ground were numerous.  Southern Living magazine's garden editor recently featured this tree in his blog.

Nuttall oak (Quercus texana)



With so many native oaks to choose from, you would think designers have no reason to pick any non-native oak.  Occasionally though you will find someone using Sawtooth oak (Quercus acutissima).   This oak is notable for its fringed acorn caps.  Some folks think it is our native bur oak (Quercus macrocarpa) when they find the acorns and search the Internet based on the acorn cap’s appearance.  The leaves are quite different between the two, however, and bur oak is not naturally found in Georgia.  The leaves of Sawtooth oak are long and narrow, not lobed, with bristly teeth on the margins.  It has no remarkable fall color except perhaps a very brief transition from green to yellow before turning brown on the tree.  Although once promoted as a “good wildlife” tree, there are plenty of native oaks that can fill this role. I found this one in a gas station parking lot.

Sawtooth oak (Quercus acutissima)


So if you’re looking for a good street tree, the four native choices listed above are ones to consider.

If you are interested in what the acorns of other native oaks look like, you can look at my other posts: New Acorns for Me and Nuts about Nuts.





5 comments:

  1. All of these oaks are beautiful. We only have the pin oak here in MN but it's not used frequently for parking lots, one reason is snow load and damage from plows.

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  2. Timely post EL! Julie and I recently departed from the unlearned masses that misidentify Willow Oak as Pin Oak. But hey, we knew it was an Oak....

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  3. Amazing Georgia Native Plants,really awesome !!

    Native Plants

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  4. Beautiful color on that Nuttall Oak! What supermarket did you find it at? I would like to see that one up close.

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