This is the continuation of an earlier post about a poison ivy plant I photographed at the Georgetown University Hospital last week. I took this picture in Rock Creek Park not too far from the hospital on the same day.
On the left is a poison ivy (Toxicodendron radicans) with its characteristics 3 leaves, in the center and to the right is a Virginia creeper (Parthenocissus quinquefolia) with its characteristics 5-leaflet leaves and covering the ground is the English ivy (Hedera helix).
Both the poison ivy and the Virginia creeper are native to eastern North America, but the English ivy is a native of Europe that is now naturalized in many parts of the U.S. It is considered an invasive plant.
As my friend Susan pointed out in her comment to the previous post, the young shoots of the Virginia creeper may have leaves 3 with leaflets, but there are likely to be some leaves with the usual 5 leaflets on the same plant, making the identification easy. The poison ivy, on the other hand, always has 3 leaves. The picture below shows a young Virginia creeper. Notice the leaf with 3 leaflets next to my thumb as well as the 4 and 5 leaflet varieties. As the plant grows, all the leaves acquire the normal 5-leaflet configuration.
Note added later: A few minutes after I posted this post I noticed that the 2 largest leaves of the Virginia creeper in the 1st picture actually have 6 leaflets each.