Botany

Hardy Kiwi: Delicious, Decorative, Destructive

Hardy kiwi vines on forest trees.
Hardy kiwi vines on forest trees.

By Jessie Griffen

While living and working at a yoga retreat center in western Massachusetts for the summer, I learned to meditate during exercise. In early August, with the end of the field season in sight and too much left to do, I jogged trails that I still needed to map. As I ran, my mind noted small observations about the forest: a patch of partridge-berry here, huge hemlocks there. Instead of focusing on these thoughts, I tried to only notice them and let them pass by. But as I turned a corner on a trail through hardwoods, downed branches and trees startled me into active observation.

A mat of green vines with distinctively red petioles blanketed the understory, and wound ominously up trunks. Stunned by the scene, I halted. A group of walkers noticed me staring. They asked jokingly if I was searching for bears. I mentioned the vines, but didn’t want to explain what I had found: hardy kiwi.

I first encountered this plant (Actinidia arguta) in another lifetime while managing a local food hub in northern Vermont. I was desperate for any locally grown fruit to sell to schools with Fresh Fruit and Vegetable Program funding. These schools had extra budget to spend on local produce, and they were hungry for alternatives to apples. When I heard of hardy kiwi, a niche crop cultivated by homesteaders and small, diversified farms, I was intrigued. I looked for a supplier but couldn’t find anyone growing the fruit at a scale appropriate to serve the industrial market.

I had seen hardy kiwi growing in friends’ gardens, but I never expected to find it growing in a nature preserve. Dead vines hang from trees in Pleasant Valley Wildlife Sanctuary in Lenox, Massachusetts, where this darling of homestead gardens is a suspected invasive. Earlier this summer, Mass Audubon led a group of eager naturalists-in-training to this site to extol the virtues of calcium in producing a carpet of ramps (wild leeks) right out of a forager’s dream. When someone asked about the vines, we heard the story of this rare, rich plant community’s narrow escape from domination by hardy kiwi, and of other nearby sites that were not treated in time to avoid complete takeover.

Whether hardy kiwi should be considered an invasive or not is a matter of great debate among a small crowd. The woody vine was introduced to the U.S. from eastern Asia in 1877[1]. As early as 1890, in a discussion printed in the Transactions of the Massachusetts Horticultural Society, professor William P. Brooks urged caution in response to the growing trend of planting A. arguta as an ornamental. “Its effects upon the trees I will not answer for;” he wrote, “its coils I fancy will be found to hug ‘closer than a brother’ […] Unless looked after far more closely than most will find time for, it will be found to overgrow all desired bounds […] and to make itself a nuisance generally by its omnipresence.”[2]

Despite this warning, some estate gardens in the Berkshires at the turn of the century featured decorative A. arguta vines, and herein lies the source of the controversy. Some scientists suspect that A. arguta outbreaks in the Berkshires could have originated from these old estate plantings that were selected for their vegetative characteristics, although no research confirms this at present. These plantings may differ significantly from the modern genotypes sold to gardeners and farmers that have been selected for their fruiting traits[3]. To further complicate matters, A. arguta has been commercially cultivated for fruit in Oregon since the 1990s, with no documented invasive outbreaks[4].

To date, no conclusive research explains why A. arguta is overtaking certain patches of forest in the Berkshires, or whether it has the potential to act as an invasive elsewhere, although in 2014, two scientists published a record of an outbreak of A. arguta in Connecticut[5].

Most people, I gather, are completely unaware of the forests in the Berkshires that are choked by the vine that they grow in their gardens for its delicious fruit. When I reported my finding to Tom Lautzenheiser, regional scientist at Mass Audubon, he noted it as a new sighting. He fears that outbreaks of A. arguta may be under-detected. At a glance, one could mistake it for Asiatic bittersweet (Celastrus orbiculatus), a common invasive climbing vine that has similarly shaped, alternate leaves. Lautzenheiser echoes Brooks’ call for caution in planting hardy kiwi. Others extol its virtues as a delicious fruit, and argue for an innocent-until-proven-guilty approach. After discovering a patch taking over a forest this summer, I don’t think I’ll plant it in my garden.

[1] Demchak, K., Guthrie, R., & Hale, I. (2013, March 22). Hardy kiwifruit: Invasive plant? Or throwback to the gilded age? Retrieved from Penn State Extension website: http://extension.psu.edu/plants/tree-fruit/news/2013/hardy-kiwifruit-invasive-plant-or-throwback-to-the-gilded-age

[2] Brooks, William P. “Fruits and Flowers of Northern Japan.” Transactions of the Massachusetts Horticultural Society. Boston: Massachusetts Horticultural Society, 1890. 48-49. UMass Amherst Libraries. Web. 9 Sept. 2015. .

[3] Demchak, K., Guthrie, R., & Hale, I. (2013, March 22).

[4] Hale, Iago L., and B A. Connolly. “Actinidia Arguta (Actinidiaceae): a New Record of a Naturalized Introduction in Connecticut.” Rhodora116.967 (2014): 352-355. Print.

[5] Hale, I. L. and Connolly, B. A. (2014).

Jessie Griffen is a second-year student in the Ecological Planning Program.

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