We’ve caught you red-handed! Well, at least with your hands full of freshly picked wineberries.
The sun is shining and the butterfly milkweed is in bloom, which means that wineberry fruit will soon become a readily available snack along roadsides and other disturbed areas on the island. These flavorful, raspberry-like berries are a fan favorite for casual foragers in the summer months. You may have grown accustomed to seeing these glistening red clusters of compound fruits decorating dense, bushy thickets. But for the landscape and the native wildlife, this distinctive plant poses some serious challenges.
Japanese wineberry (Rubus phoenicolasius) is a thorny, perennial, herbaceous shrub that shares similarities with its relatives in the genus Rubus such as the native common blackberry (Rubus allegheniensis) and black raspberry (Rubus occidentalis). Unlike its native counterparts, wineberry’s stems and flowers are covered with small, dense, red hairs that are slightly sticky to the touch. This common invasive offender was originally imported to the United States from Asia in 1890 to be used as a breeding stock for Rubus cultivars. Its incredible pest resistance, ability to adapt to a variety of conditions, and deliciously aesthetic fruits made it highly sought after. These same characteristics, however, have prompted explosive spread across its non-native range since wineberry escaped cultivation and began growing invasively in the 1970s.
Today, we can see the lingering consequences of this infestation in many disturbed settings. Forest understories are threatened by wineberry’s aggressive growth patterns, which shade out native vegetation and form dense thickets. Even old-growth forests can be impacted if this persistent spreader gains entryway through a narrow disturbed strip or by natural seed distribution. Similar to its native relatives, wineberry produces long shoots that can re-root at the end to establish new growth. But unlike the native species, wineberry does not require cross pollination from another plant to spread viable seed, which may allow for more prolific reproduction. In many cases, wineberry easily outcompetes native vegetation, transforming original landscapes and diminishing their functions.
The problem lies with non-native vegetation, like wineberry, replacing plants that an ecosystem depends on. Animals rely on the native vegetation that they have evolved with over time. Specific relationships form between animals and plants, and in many cases, these connections cannot be sustained by substitute species. As wineberry impinges on intact native ecosystems, it outcompetes other important fruit-bearing plants that feed wildlife and in turn rely on them to spread their seeds. Specifically, many landbirds completing autumn migration rely on native fruits to fuel nutritional needs throughout their journey (Gallinat et al. 2020).
A 2020 paper published in the journal Biological Conservation found evidence to suggest that birds seek out the fleshy fruits of native vegetation even when non-native fruit is more abundant. This is likely because native berries often contain more important nutrients like fats and carbohydrates which birds need to complete migration and survive in the winter. A 2013 paper published in the journal Northeastern Naturalist found drastic differences between the fat composition in invasive species and their native alternatives. Japanese honeysuckle, multiflora rose, buckthorn, autumn olive, and oriental bittersweet berries all contained less than 3% fat, whereas the native fruits of bayberry and arrowwood both have roughly 50% fat (Smith et al. 2013).
As the climate changes, many birds are arriving to stopover sites later in the season than they traditionally have, causing them to be unsynchronized with native plant fruiting periods (Gallinat et al.). Since invasive plants typically produce fruits later in the season, their nutrient-deficient berries are more readily available. Despite this shift in phenology, migratory birds have been observed seeking out native fruits to fuel their migration even when their numbers are dwindling (Gallinat et al. 2020).
In short, non-native berries like wineberry are the fast food of the natural world. They are abundant, readily available, convenient, and even tasty, but they don’t provide the necessary nutrients for wildlife to maintain optimal health and function. When they do get eaten, invasive seeds are spread long distances, launching a vicious cycle.
To help reclaim space monopolized by wineberry, consider planting native shrubs that will provide nutrients for wildlife and contribute to natural forest understories. Black chokeberry (Aronia melanocarpa), American holly (Ilex opaca), bayberry (Morella caroliniensis or M. pensylvanica), arrowwood (Viburnum dentatum), and inkberry (Ilex glabra) all fill that niche nicely.
If you have wineberry growing on your property, reduce potential spread by managing it before it goes to seed between late spring and summer. The Invasive Plant Brigade is here to help if you require assistance removing wineberry or other invasive species from your land. And if you happen to miss a bush, then you’ll have a great excuse to eat a whole lot of berries!
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