Invasive Hardy Kiwi “amphitheater” in Lenox MA. What at first glance appears to be a lush tropical jungle is in fact temperate forest.

Overtaking forests in Berkshire County (MA), Long Island (NY), and Morristown (NJ), hardy kiwi (Actinidia arguta) has biologists and conservationists alarmed. Originally planted as an ornamental vine, it is now exhibiting invasive qualities and having a deleterious impact on habitat, biodiversity, and resiliency. In response, BEAT, MassAudubon, and and a variety of groups from across the region are banding together to stop this invasive before it becomes uncontrollable.

Beginning as what appears to be innocuous ground cover, hardy kiwi grows up and over itself and other plants, establishing a “mat” of vines several feet thick. These mats block sunlight from reaching the forest floor and out-compete native ground cover. From there vines shoot up to the tops of trees creating what look like “curtains”. These curtains pull trees to the forest floor and create large gaps in the canopy. This combination of thick mats, curtains, and large canopy openings is called an “amphitheater” because it looks like large open-air venues.

Traditionally thought to be non-invasive due to its lack of distribution, mapping efforts by BEAT and MassAudubon provide unequivocal evidence of the species jumping spatial gaps

Kiwi in Pittsfield MA, just starting to “mat” and create “curtains”.

(dispersing). According to Mass Audubon

(2015) “Hardy Kiwi fruits are eaten by raccoons. Other mammals, and possibly large birds such as turkey and ruffled grouse, are also expected to consume the fruits and disperse the seeds. If both staminate and pistillate plants are present, and seeds are animal dispersed, especially bird dispersed, fruits could easily jump large spatial gaps (Mass Audubon, 2015).” It may also spread vegetatively (Weatherbee, 1996). These methods of dispersal allow both rapid and widespread dispersal. This is of large concern if management is to stay ahead of hardy kiwi and protect any other vegetation or ground cover underneath it (Mass Audubon, 2011).

For more information on Hardy Kiwi please refer to the links below. If you think you know of an unmapped kiwi population please contact BEAT.

History and Origin

Morphology and Distribution

Management Options