Can and should Lobelia be trimmed down hard to enable regrowth and reflowering?

The trailing one does start to look a bit like this,,and yes,you can trim it back.I do it with all mine,and it will reward you with lots more growth all summer.I have known it to seed itself in the pot or basket,and appear the next year..so go for it..:o)

So it is as I expected. Thank you Bloomer. An instinct told me so. I do not know whether mine are trailing type, but are a mixture of old and new varieties by T and M. Time for a big hair cut.

I cut mine back in late June, early July, and its only just starting to flower again now. It may be that if you trim yours now, by the time it flowers again it'll be very late in the season, but do it anyway if you want to.

Well these are T and M mixed old and new varieties. They claim that unlike the old varieties only, this combination is able to go on flowering until late, even as late as October. Not much hope for this basket otherwise, so chop it is.

Hmm, sounds like sales balderdash to me - my Lobelia, an old variety, flowers till the first frost every year anyway... but my money's on an Indian summer in autumn, so cut it anyway, looks a bit straggly in places, doesn't it.