By Cornishsally
Cornwall,
United Kingdom 
Someone earlier in the year asked a qustion about Cosmos not flowering but I can't find it. I wondered if their's ever did flower? Mine grew over 7 feet tall - enormous healthy plants & not a flower between them. Eventually most of them got knocked over in gales, leaving one remaining strong stem - which is now covered in flowers. How barmy is that!
20 Oct, 2010
Answers
Thanks Anchorman - that's interesting as I'd improved the soil in that particular bed quite a bit this year. The flowers are still coming, and there are lots of buds too! Next year I will treat 'em mean and hope to habe less plant and a lot more flowers earlier on.
3 Nov, 2010
Previous question
I've found some Cosmos don't ever flower. I suspect it might be due to the richness of the soil.
The way I get around this is to pot the seedlings on into 7cm square pots and don't give them any fertiliser. They will stay a bit stunted but after a few weeks will form flower buds. At this point you can plant them in the ground and they'll flower to late autumn
20 Oct, 2010