Bittersweet Nightshade

Today’s PEI plant is one that I’ve received many questions about, along with a request to do a post on it. So, meet Bittersweet Nightshade (Solanum dulcamera)!

If these flowers remind you of tomato or potato blossoms, give yourself a gold star. Bittersweet Nightshade is in the same family (and the same genus) as those domestic crops, and is related to other familiar species including eggplant, peppers (both sweet and hot), gogi berries, and tobacco.

Bittersweet Nightshade is not native but was brought to North America from Europe in the 1800s as an ornamental and medicinal plant (it was once taken internally as a sedative and used externally for treating skin infections). David Erskine’s work in the 1950s found Bittersweet Nightshade restricted to areas around Ellerslie, Charlottetown, and Murray River. Today, this plant is widespread in all three counties, and is considered an invasive species.

This perennial, climbing vine can tolerate shade, allowing it to spread into natural habitats including forests and streamsides. Along streams, especially, Bittersweet Nightshade can be problematic: it chokes out native vegetation, reduces diversity, and can reduce waterflow, resulting in impacts to both terrestrial and aquatic life.

Bittersweet Nightshade is perhaps best known for its toxic berries, although the danger is overstated in my opinion. All parts of the plant contain a toxic chemical called solanine – also found in potatoes, in lower levels – with concentrations highest in the unripe berries. The plant does NOT contain the highly toxic chemical atropine, found in its relative, Deadly Nightshade (Atropa belladonna). Bittersweet Nightshade should not be consumed, but it is far less toxic than all sorts of other PEI plants, including Water Hemlock (Cicuta maculata), Ground Hemlock (Taxus canadensis), and even the domestic Lily of the Valley (Convallaria majalis) many of us have in our gardens.

While they are toxic to humans, Bittersweet Nightshade berries (inset photo) are eaten and spread by birds. If this species has found its way to your property and you want to get rid of it, you have some work ahead of you. Repeated pulling will weaken and eventually eradicate the plant; if you can dig up and dispose of the roots, even better. Bittersweet Nightshade can spread from fragments, and so mowing or whipper-snipping is not recommended. Collected material should be sealed in a plastic bag, labelled ‘invasive species’ and put out with your waste.

Bittersweet Nightshade is widespread and well-established on the Island. While we may be able to control it in isolated areas, it’s likely to remain part of PEI Untamed!