Rick Dyer takes Japanese barberries personally. As a professional forester he has seen the barberry scourge invade Eastern woodlands and he has witnessed the startling robustness of the aggressive, non-native import on coastal islands such as Monhegan.
Two years ago, when he was studying for a master’s degree in Forestry at the University of Maine, Dyer took part in what he thought was going to be a fairly benign study of forest health and land use history on Monhegan. As he and his partners studied the landscape, however, they found the extent of barberry infestation on the island alarming. “I was amazed at how thick it was and how fast it was spreading,” he recalled. The Monhegan barberry invasion (WWF Sept. 2003) shaped his beliefs about what is right and wrong in Eastern forests. His stand against the proliferation of the bush has become almost a moral cause and can even touch him emotionally. The effort to limit the barberry’s spread “… is going to be a constant struggle,” he said, “and there seems to be a lack of interest about the problem on the islands. It gets me down sometimes.”
Dyer is not alone in his concern. Though many islanders seem to shrug off the infestation as tolerable and are resigned to its spread as inevitable, owners of smaller parcels of land can easily observe the negative ecological and visual impact of a barberry assault on their property. They rally against the bush with the fervor of converts to faith; with the conviction of soldiers at war.
Once Dyer and his partners were able to persuade Monhegan residents that the barberry was a threat, he recalls, small groups of residents scheduled forays into Monhegan Associates’ land. During these raids, the bushes were hacked, sawn and treated with herbicide. Dyer remembers great piles of the stuff heaped onto a ballfield. While on assignment, Rick would spend his weekends cutting.
The barberry problem is similar on many Penobscot Bay islands, and its origin has cultural, biological and aesthetic roots.
Early Americans cultivated the common barberry as a source of berries for jams. When it was discovered that the common barberry had a role in perpetuating a disease that infested wheat, Americans switched from the common to the Japanese barberry not just for use as a source for jams, but also as an ornamental hedge.
When asked why people don’t change their choice of hedge from the annoying barberry to something less threatening and native like the bayberry bush, with its appealing aroma, thick leaves and small waxy berries, Dyer blamed the home landscape industry for resisting changing the products that Americans are familiar with because it will reduce profits. “We have no allies in the horticultural industry,” he said. Ironically, contractors will buy barberries for landscape projects and add to the infestation when there is already an abundance of the bushes, free for harvesting at roadside.
The barberry is also popular is because it turns maroon and red in autumn. Dyer explained that people prefer a bush that does something more than staying green all the time. “I go nuts when I travel through New York and New Jersey. People have barberry bushes in their front yards! I take it personally. It has yellow roots! It’s got to be an alien!” he exclaims.
When so few people have been taught that the barberry is the source of a serious threat to the American forest, and when they’ve been living with barberry hedges for generations, Dyer holds little hope that the popularity of the barberry can be reduced.
The barberry’s main method of dispersal is birds. Birds are attracted to the bright red berries, eat them and expel the seeds onto the ground. “Here in Massachusetts even wild turkeys spread the barberries around,” said Dyer.
Persistence and manual labor are the primary weapons against the spread of barberries, he says. Cutting the bush and immediately treating the stump with fifty-percent Roundup will kill a bush. Plucking new shoots off of an old stump will starve the roots for carbohydrates and kill a bush that threatens to re-grow. A property owner needs to devote at least two full years to eradicating and monitoring a limited area of infestation in order to achieve a small victory – but because seed dispersal is so effective and impossible to control, the barberry will return.
Barberries grow almost anywhere except in very moist ground and exceptionally well-shaded areas. On Monhegan, dormant barberry seeds would sprout vigorously when stands of white spruce fell down and the sun shone on previously shaded ground but “when we cut the barberries, Asiatic bittersweet grew in its place,” he groaned. “Yet another invasive species to cope with!”
Dyer would like to return to Monhegan and observe the progress that has been made against the barberries there. As he was leaving the island after the study Rick felt as if he might not have persuaded enough people that the presence and spread of the barberry was worth their serious consideration, but then he saw something that lifted his flagging spirits,
“It was a couple of weeks after I made my presentation to the Association and the island people about the study. I didn’t feel as if there was enough interest to motivate the residents to take back their island from the barberry. I was walking toward the boat as I was leaving the island and passed by the house of a guy who I’d never met but who I wanted to talk with because he had a very old and thick barberry hedge in front of his house. The trunks of the bushes were real thick as if the bushes had been among the first barberries on the island. But I saw that he had cut it down – cut the hedge right down. It was one of the last things I saw as I left the island. It meant everything to me.”