When to cut the agapanthus back

Well, agapanthus are a noxious weed and spring back whenever you prune - we used to cut back ours all the time as the grew along a driveway and could make reversing hard if they grew too long :o)
But they went NUTS and we pulled them out eventually.
Anyway, you probably won't kill them even if you mutilate them with a chainsaw or something. But I would probably just pull the flower stems out at this stage if you want them looking lush (I have to admit, severed agapanthus leaves aren't a good look). And when I say pull, I mean pull: you'd be surprised at how easily they come out of the plant, you probably don't need secateurs.

Hope this helps (I do rabbit on, don't I?)

I would certainly cut the stems off at the base of the stem. unless you want seeds of course.

I wish my agapanthus grew like a noxious weed! I have mine in a pot and they are so contrary. I have one flower this year. I want fields of them!!

oh yes i agree cammomile.

I agree with Camomile too . My potted Agapanthus are really reluctant to bloom. Bit better this year but still disapointing. Perhaps Guerilla gardeners could take note and plant them out on their sites as a really persitent plant.

I agree. I have waited three years for mine to flower.They're in a pot inherited from my mother. She planted some "super duper, enormous blue ones" - her words. Three years on they' are now in flower - guess what - they're white!!

My potted agapanthus used to be a poor turn- out until I started feeding them about once a month with my other pots through out the whole year and now they are fantastic loads of flowers ,when I say feed, I pour in a splash of tomato liquid feed into a large watering can !
easy peasy