Tree of the Month: Overcup White Oak
Our Insights on the Overcup White Oak
Quercus Lyrata
The overcup oak is a swampy native to the warm bottomlands and wetlands of the southeast. A member of the white oak family, it’s a particularly hardy species whose resilient characteristics, such as flood and drought tolerance, make it an excellent option for urban areas like Nashville.
Characteristics of the Overcup Oak
While this tree isn’t as common around Nashville as other oak species, the overcup oak (Quercus lyrata) is a big canopy tree that can offer a lot to a landscape! It’s a somewhat slow-growing tree, taking on between one and two feet per year, but it will grow into a mature specimen (to a height of up to 70 feet) with a full, bushy crown.
These robust trees are native to the bottomlands, riversides, and flood plains of the humid south, including western Tennessee, where the species is used to strong rainstorms, flooding, and some drought in the hot summer months. An overcup oak loves to grow in full sunlight and can tolerate most soil conditions, but it would prefer slightly acidic, well-draining ground.
In particularly wet conditions, the overcup oak may have a wide root flare and tends to have a shallow root system. This surface-level rooting habit allows the tree to receive oxygen in moist or clay-heavy soil that doesn’t drain well or when water levels are higher than normal.
The bark of overcup oak trees is ash gray and lightly flaky, but not as flaky as some other white oaks. The overcup’s leaves have rounded tips, but the lobes are somewhat pointed, with both deep and shallow sinuses (spacing between the lobes). They have a longer and more stretched appearance than other white oak tree leaves. In the fall, this oak tree turns a golden orange color.
The tree receives its common name, overcup, from the large, encompassing cap that creates a cup over the majority of this species’ acorns.
Overcup Oak vs. Swamp White Oak
The overcup oak (Quercus lyrata) and swamp white oak (Quercus bicolor) have some things in common, such as being native American white oaks, hosting important pollinators and local wildlife, and having a tolerance for wet soil, flooding and drought, but a few defining characteristics set them apart (substantially and superficially) from one another, adding to the biodiversity of the Nashville area:
Temperature Tolerance – Both swamp white oaks and overcup white oaks tolerate temperature variation, but the swamp white oak, being native to the northern portion of the eastern US, can tolerate lower temperatures than the overcup oak, which is native to the southern states of the eastern US. Luckily for Nashville, their range overlaps in western Tennessee, and we can plant both here!
Leaf Shape – The swamp white oak has a wide, round shape with shallow sinuses, resulting in wavy edges. Overcup oak leaves have long lobes, deep sinuses, and slightly pointed tips. However, the overcup’s pointed lobe tips are rounded, as with all white oaks. This is in contrast to the sharper-looking red oak leaf, which has a bristle on each pointed lobe.
Bark – The bark of an overcup oak tree forms in flat plates, while the swamp white oak’s bark forms in deep ridges. Aside from their leaves, the bark formation is the easiest way to tell one of these trees apart in Nashville, especially during the wintertime after both species have dropped their leaves.
Is the Overcup Oak a Good Tree?
The overcup oak tends to be found in clay-heavy soil in areas with high precipitation levels and regular flooding. While it hasn’t been as popular a species as other types of white oak trees, the overcup oak has niche tolerances that make it a great tree for the Nashville metropolitan area, including resilience against flooding and heat and adaptability to various soil types.
In addition to being durable, this tree has a long lifespan and can live for centuries in the right spot. A long-lived, mature specimen performs a wide range of important ecosystem services, including air filtration, stormwater management, erosion control, and shade provision, all of which keep local environments healthy and comfortable year after year.
If you’d like to add one of these strong trees to your yard, check out the overcup oak’s listing with the Nashville Tree Conservation Corps’ tree sale! Sign up to volunteer, and be sure to subscribe to our email newsletter for regular updates and tips on canopy care in Nashville!