Oaks are generally split into two groups: "red" and "white." Red oaks have leaves whose lobes come to a point, with a little bristle on each point. Their acorns take two years to mature, so even as they're dropping this year's crop, they've already got half-grown acorns for next year. White oaks have leaves with more rounded lobes, typically lighter-colored bark, and their acorns take only one year to mature. But even within those two groups, there's a wonderful diversity of acorn shapes and sizes. Below are a selection of some of the acorns you might see in the greater DC area. (We've tried to line them up so they're to scale.) How many can you find in the wild?
|Northern Red Oak|
|Southern red oak|
|Black oak |
|Swamp white oak|
One way to really get familiar with acorns is to collect them for Growing Native. The Potomac Conservancy will use them to replant buffer zones along the Potomac and its tributaries. This improves water quality and provides important wildlife habitat. You can donate collected acorns until October 26 in Virginia and October 31 in Maryland and DC.
All photos by Steve Hurst at the amazing USDA-NRCS PLANTS Database, except the post oak acorns, which are from the magnificent old tree here at The Natural Capital headquarters.