A Quirky Quercus: Shingle Oak

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I have been fascinated by a group of trees planted at my county park headquarters in Medina, Ohio.  They’re handsome trees… large and stately with low drooping branches you can shade under (Or get whacked with when mowing the lawn).  I always pause to admire them, and if it were not for the acorns... I never would have known they are oak trees.



A full grown shingle oak against a blue sky showing its pyramidal form and drooping lower branches



This is Shingle Oak, Quercus imbricaria.  Like other oaks, this is a deciduous hardwood and is native to Ohio.  It grows skyward to 50-60 feet (some maxing out 100+ feet) and has a lovely pyramidal shape when young, growing a looser canopy as it matures.  It sports some cute little acorns and has great movement in the wind.



But what it does NOT have... are lobed leaves classic to other familiar oak trees in the genus!  



a bundle of shingle oak leaves showing that the leaf blade is willow-like not lobed as other oaks


the familiar acorn of oak



This "disguised" oak is a member of the red oak group.  Red oak acorns mature over a 2 year period. In their second year, as they mature and prepare to drop, shingle oak acorns will turn dark green to almost black! 



shingle oak acorns mature into a dark dark green or black color



Another ID character for red oaks is the presence of a bristle tip or fine hair at the tip of each leaf lobes.  In the case of shingle oak, it has only one "lobe" with its willow-leaf shape, and so has only one bristle tip. 



members of the red oak group have a bristle tip at the end of its lobes



It is considered Ohio's only native oak species with no lobes nor teeth on its leaf. However, other lobe-less oaks do exist in the US!   Further south, Willow Oak, Quercus phellos; Laurel Oak, Quercus hemisphaerica, Florida Oak (Quercus inopina) and several others carry that smooth-margined, narrow-leaf look.  You can find more in this great field guide to native oaks from the USDA.



Like most trees, if we have moist well drained acidic soils, shingle oak will be happy… but this tree is also suitable for alkaline and clay soils which makes it a great choice for soils in many of my areas of Medina. Bud burst gives us a slightly reddish young leaf, darkening into a shiny, rich dark green through the season and a faintly white/grey, pubescent lower leaf surface.  Fall color is not always splendid but can surprise us with yellow to russet-red colors.  Not bad!



It is described by Michael Dirr as a great tree for the Midwest, suitable for windbreaks, like the photo below, and it does well in our colder zones 4-6 and may struggle in warmer zones.  It is adaptable and easy to grow.




shingle oak lined up as a windbreak at a parking lot edge



It is a hard, hardwood.  It gets its name because their strong timber was historically used to make shingles, thus giving it the common name, "shingle" oak. But in present day landscapes, that strength means it's less prone to storm breakage… bonus!  While it is considered a common tree, found along fence rows and forest edges... I don't see it often in landscapes.



Another interesting observation at this location is the myriad of oak insects and oddities bespeckling these trees. Oak trees are SUPER FOOD for insects.  Oak trees can be a host plant for over 400 species of moth or butterfly. There are all manner of sawfly, leaf miner, gall-making wasps and flies, and scale insect that feed on oaks too... and the oaks can handle it.  But some gardeners might find that much activity intimidating. 


spent horned oak gall
They did a good job pruning galls away, but i found one dead lower branch still sporting a spent oak gall.


While none of its pests are considered serious, it can be susceptible to some gnarly looking galls like horned oak gall (Callirhytis comigera) or gouty oak gall (Callirhytis quercuspunctata), both cynipid wasp gall makers.  When I first saw this tree, it was covered in galls. And that can be an alarming sight to the uninitiated.  Unless you’re gall-enthusiast Joe Boggs, then it’s a feast for the eye! (Read more about the intricate lifecycles of horned oak galls in this fantastic article by Joe on horned oak gall.). But these stem galls can cut off the flow of nutrients along stem tissue, and lead to stem dieback and the need for a good prune up.  


It also tends to hold onto its dead, lower branches. 


the lower branches of shingle oak can die back and linger on the tree for a long time


But a good pruning from our park friends has seen these trees to right again.  No chemical control is recommended for galls and so this is a tree that you're just going to have to enjoy with all its literal lumps and bumps. But if you like strange insect critters then there is no tree better than an oak.