What's eating my Lobelia

mackergxz6UQGT1

Every time it puts up a flower stem something eats it from the base ,the thing is ,the leaves are not touched

Perki

Slugs / Snails like these varieties of lobleia. They've never touched my Lobelia Hadspen purple though but that has hairy leaves which I assume puts them off. 

mackergxz6UQGT1

Thanks ,I'll be out with my torch later ,might bring some salt