Wide spreading vine, creeping along the ground and climbing trees and cliffs by adhesive rootlets. Leaves of two kinds. Juvenile leaves bluish green, sometimes marbled with bronze, with pale green veins, with 3 to 5 lobes. Mature leaves (below left) green, oval, pointed, unlobed, Mature leaves form only in open sunny areas, usually at the tops of trees or cliffs. Flowers green, with 5 sepals and 5 yellow stamens, in a ball-like cluster. Fruits (below) blue berries in a ball-like cluster. Flowers and fruits rarely seen as they are produced, like mature leaves, mostly at the tops of tall trees and cliffs.

An extremely nasty invasive exotic, despite the attractive foliage. It smothers plants on the ground and can smother trees that it climbs. Spreads through pieces rooting, and also from seeds dropped by birds that eat the berries. The berries are somewhat toxic to native birds, although supposedly not to starlings, which are also nasty invasives. Do not let this plant grow in your yard; rip it up!! Fortunately not too common in Wildwood, but can be seen in various spots throughout the Park, especially on the tree-of-heaven (another invasive) at the entrance, and on the cliffs above the upper Northeast Trail, at the top of the Main Street Staircase.

True English ivy (H. helix) is almost identical. The leaf color, shape and size are variable in both species and overlap. English ivy tends to have white instead of green veins. More definitively, the tiny hairs on the leaves tend to be wide-spreading in English ivy and flattened against the leaf in Irish Ivy. Irish ivy evolved from English ivy by duplicating all its chromosomes. Since the two now have different chromosomes they cannot interbreed and are different species, even if they are so hard to tell apart. English ivy is also an invasive exotic, but most invasive ivy is said to be Irish.