This is the time of year when it becomes apparent that porcelain-berry is making a bold attempt at taking over the world. Or at least vast swathes of Virginia’s forests, especially those near urban areas. Suddenly those white flowers and multi-colored berries are appearing on what seemed yesterday to be innocent green vines…in fact, didn’t you think yesterday that those were grape vines?
Experienced weed warriors know the difference, but to the casual observer, the invasive exotic porcelain-berry, (Ampelopsis brevipedunculata), does bear a strong resemblance to our native grapes. Both, in fact, are in the same family, Vitis.
And to complicate matters for people trying to learn to identify it in the field, the leaves of porcelain berry can assume greatly varied forms, even on the same vine.
Thankfully, an easy ‘tell’ shows up this time of year for those struggling with ID. The inflorescence of the P. berry vine is a cymose panicle – its umbrella-shaped top sticks up. The berries also are held upwards, even when the vine is dripping downward. For more tips on P. berry ID, click here: Porcelain-berry Fact Sheet
The inflorescence of our native grapes are panicles that are broad at the base, tapered at the tip, and droop downward, as do the fruits that follow, just like the grapes you are used to seeing in vineyards. Harder to find photos of the native grapes around the urban areas, too, click here to see some: Native Vitis
Listed by the Department of Natural Heritage in the ‘Highly Invasive’ class, porcelain-berry is a serious threat to our native plant communities. Like all the plants called invasive exotics, it grows rapidly and has few pests because it did not evolve here with the checks and balances of competition from the plants and animals that live here. Instead it takes the place of the plants that supply the resources our native wildlife needs. The Flora of Virginia describes it as “A troublesome, shade tolerant invasive species capable of strangling native forest vegetation.”
At Dyke Marsh Wildlife Preserve in Alexandria, porcelain-berry is one of the top seven invasives the National Park Service (NPS) has targeted for removal. Quite a number of Virginia Native Plant Society members have taken the Weed Warrior training the NPS offers, and meet there to engage in the rewarding work of freeing up the natives so important to the marsh ecology.
Ken Adams, currently the Warrior-in-Charge at the Dyke Marsh location,demonstrated some useful techniques recently for battling the thick top layers of porcelain vine that blanket large areas there. Often it is impossible to know what plants are still alive under the P.berry vine, which kills what it grows over by blocking the sunlight.
First, lift the vines up and away, and then begin to cut through the stems. The NPS system calls for leaving the plant material onsite, allowing nutrients and organic matter to be kept in place, unless ripe seeds are present. As a wider hole begins to open up, it is easier to see what is underneath and to see where to make more cuts. This method works with any of the other invasive vines as well. Work in a circle if possible, to let the light reach inside the ‘tent.’ Native plants still alive under the covering will regenerate with access to sunlight. Be sure to cut the vines that are connecting to nearby plants. The tree under this mass had been covered for too long, it had died. However, many natives have been released from their invasive prisons, like this lucky spicebush, (Lindera benzoin), so pleasantly fragrant to work around.
Serious methods are needed to completely eradicate the porcelain-berry plant, but cutting back the fruiting vines right now is a helpful step to take.