It’s so hard to find landscaping with winter interest. Once mid-December hits and freezing temperatures are commonplace, most fall foliage color is gone. Very few flowers and flowering shrubs are blooming either.
Carolina jessamine (Gelsemium sempervirens) still manages to display some yellow funnel shaped flowers, though the full display won’t be realized until spring. Lately mine have been glorious.
Once established, this perennial woody vine really makes impressive growth. Smooth edged evergreen leaves emerge from stems in pairs. This time of year they begin to develop a bronze cast. Foliage growth has stopped for the year, but flowers will pop out periodically throughout the winter during mild spells.
Plants tolerate a wide variety of soils. When they are young they require moist sites but once they become established they tolerate drought very well. Jessamine also has few disease or insect problems.
It’s not a huge fertilizer user but it will respond to regular feeding. It’s important not to over fertilize with nitrogen. Foliage might be gorgeous but flowering will be impaired.
This aggressive vine thrives in full sun. It also performs quite well under partial shade, though blooming is much better in sunny places. Plants can be pruned during any season. In sunny spots with regular pruning it can even be maintained as a ball shaped shrub.
I don’t like to trim them during fall as the chances of winter kill are greater. However, if plants die back some they can be pruned back severely in spring and rejuvenated. Once established they are hard to kill. They even make a good ground cover on steep slopes.
Jessamine covers a fence or trellis with glossy leaves and deer will leave it alone. There’s good reason for that. Every part of the plant is poisonous. Pets generally won’t touch it, but if plants are ingested they could potentially cause problems.
Symptoms of jessamine toxicity are muscle weakness, paralysis, decreased respiratory rate, hypothermia, difficulty swallowing and breathing, vision problems and seizures. Eventually if left undiagnosed pets could die. Alkaloids gelsemine, and sempervirine are the two major toxic substances.
Numerous sources state medicinal uses for the rhizomes of this plant. Preparations from these underground stems are used to combat fever and severe coughing. They’re also used for some nerve problems like sciatica. I urge not trying it unless specifically prescribed by a licensed herbalist. Dosage mistakes could be fatal. Less than a teaspoon of crushed rhizome could kill you.
Carolina jessamine is native to our area. For that reason alone it is often coveted for landscape use. Plants can spread into adjacent areas but their invasiveness is far less problematic than that of other woody runners like trumpet vine, Japanese honeysuckle or wisteria. I’ve never seen Carolina jessamine crowd out and kill other vegetation like those do.
Still, since they are a vine they must be contained somewhat. If that is a problem maybe they aren’t for you. As for me, I like color and this vine has got it. Best of all, it often blooms when little else does.
Ted Manzer teaches agriculture at Northeastern High School.