Well, I am in love with its bright red berries especially this time of year, but they are the reason why this plant has so successfully naturalized here. Birds eat these berries and expel the seeds elsewhere. Crows, eastern kingbirds, mimic-thrushes, thrushes, white-crowned sparrows, and waxwings eat the berries of bittersweet nightshade. In the Northeast, numerous other songbirds, game birds, and some mammals also eat the berries. Gray catbirds have been known to nest in bittersweet nightshade. But most interestingly, it is a recognized major food source for bumble bees and this I can attest to because it is rare to see one of its purple blooms (resembling a tomato flower) without a bumble bee clinging to it during the summer in spite of all the other plantings I have! Also, its leaves are quite "holey" throughout the summer so I believe them to be a food source for some type(s) of insects. The Nature Conservancy has given bittersweet nightshade a national ranking of "low" based on its overall low ecological impacts, but are moderately concerned about its widespread distribution and abundance.
Hmm, yet another native dilemma! A naturalized non-native that offers some wildlife value and a major source of food for bumble bees (who are declining). I think I will save a patch of this climber for now. As my garden matures and I add more berries and pollen sources (perhaps specifically for bumble bees), I can slowly phase this plant out. I would be interested in knowing what you would do.
Sources for this post include Lady Bird Johnson Wildflower Center and the US Forest Service.
