There’s a scrambling vine in my garden, which I’ve trained onto the post of the pergola. For much of the year it is wiry with small, shiny green leaves but as winter comes round it turns on a show. As winter burgeons into spring the Carolina jasmine (Gelsemium sempervirens) masses itself with small bright yellow tubular blooms. In warmer areas it flowers while it is still quite wintery.
I love this dainty climbing plant and, until I started to write this blog, wouldn’t have hesitated to recommend it for any garden because, as well as having bright yellow flowers in late winter when everything can be a bit bleak, Carolina jasmine is a gentle climber. It isn’t a thug like the other jasmine flowering in my garden at the moment, Jasminum polyanthum. It can be grown as a ground cover but is seen at its best trained upwards to twine up and over an arch or a fence. It easily reaches 5m high. Carolina jasmine will also grow in a pot making it handy for growing on a sunny or partly shaded balcony. It is tolerant of frost and will grow from the cold temperate regions to the hot tropics.
I have the single form, but there is double flowered form that I have seen listed as ‘Pride of Augusta’ or ‘Flora Plena’.
But there’s more to this plant than I knew. I know common names can be misleading and as I knew this wasn’t a true jasmine, I thought I’d delve into this plant a little more deeply. Sure enough there are hidden depths.
So, is this plant from the Carolines? And, is it a jasmine? Well, yes and no. Yes it may be found in the Carolines as it is native to the southern US, but it’s a negative on the jasmine link.
Although gelsomino is the Italian name for jasmine and it is commonly called Carolina jasmine and has a sweet perfume, Gelsemium isn’t a jasmine – not by a long chalk.
The jasmines are in the olive family (Oleaceae) while Gelsemium isn’t.
Just where to place Gelsemium sempervirens is a bit tricky as it is variously classified as part of the Loganiaceae or, since 1994 after a splitting up of the family, placed in its own small family of Gelsemiaceae, which it shares with a tropical plant I don’t know called Mostuea. One of the issues is that Gelsemium doesn’t have milky sap like the rest of the Loganiaceae.
Loganiaceae is a family of mainly tropical and subtropical plants that contains several poisonous genera including Strychnos (the source of strychnine) and Gelsemium. My copy of ABC Flora notes that Gelsemium sempervirens is poisonous but it doesn’t expand on which parts are dangerous or how poisonous. Certainly, nothing ever eats it. Black fruits form occasionally after flowering and these may be the culprits. All that’s apparent now however are a few dry brown capsules that have split open to release some papery seeds.
Now I know it’s poisonous however I’ll be on the look out for these fruit after flowering and prune them off. Of course, as soon as I went out to take a closer look at my plant my ever-helpful pug Dora started chewing on one of the lower branches. I stopped her, not wanting to find out the hard way whether or not it has poisonous sap!