Overcup oak is one of the most flood-tolerant oaks in all of North America, often growing in and around wetlands and floodplains. Not only can mature trees handle weeks of having their roots and trunks completely submerged, the cap that completely covers each acorn causes the acorns to float so young trees can root in far enough away from the shade of their parents to get established.
Caterpillars are of particular benefit to nesting birds, and oaks are one of the most beneficial trees for wildlife. They offer food, shelter, cover, and nesting sites for a number of animals.
Plant Characteristics:
Reaches 40-60’ tall.
Does best in full to part sun.
Prefers average to wet soil, tolerates flooding and drought once established.
Yellow-green flowers appear in spring, followed by acorns that ripen into fall.
Wildlife value:
Oak trees feed 477 species of Lepidoptera larvae in our area, including the spun glass slug, red-spotted admiral butterfly, and the funerary dagger moth.
The branches, nooks, crannies, and hollow areas in oak trees afford protection from the elements, a place to rest, safety from predators, and nesting areas to raise young. Many animals feed on the small twigs, buds, shoots, and leaves of oaks, as well.
Oak trees attract hundreds of insects and invertebrates that feed on their foliage. These insects, in turn, attract insectivorous birds, reptiles, frogs, and I’ll pop mammals developing a very dynamic food web within the forest. Because oak trees attract such a wide variety of insects, they are considered to be one of the most important trees for woodland dwelling birds.
Medicinal, Edible and Other Uses:
The seed can be dried, ground into a powder and used as a thickener, or mixed with other grains for making bread. The seeds contain tannins, a bitter digestive inhibitor that can be removed or reduced by thoroughly washing the seed in running water (tannins are more easily removed after grinding). A simple taste test can tell when the tannin has been mostly removed. The traditional method of preparing the seed was to bury it in boggy ground overwinter. The germinating seed was dug up in the spring when it would have lost most of its astringency.
The roasted seed is a coffee substitute.