"Syke" wrote in message
...
I sowed some of these in the greenhouse and planted them out in June as it
was a cold spring this year. The seed packet said height 2', but they have
grown to about 5'. They are lovely and bushy with a lot of flower, but
because of the unexpected height they have been grown towards the front of
the border and with the result are hiding other plants. Should I have
planted them out sooner?

No-one else has replied, so I've give you my two-penn'orth FWIW.
I'm not exactly experienced with Cosmos, having only grown it a few times
(my greenhouse deceased in a gale..) but I cannot see how planting them out
earlier would have reduced their ultimate height (if that is what you were
suggesting)?
If I buy seeds that promise 2' high Cosmos, although what I grew were a bit
taller than that, that is what I expect to get. 5' is a bit extraordinary.
They were not struggling for light at all were they? If not I might mention
it to the seedgrowers.
If my greenhouse was up and running I'd definitely grow them again, also
nicotiana in mixed colours. I used to go out into the garden in the late
evening just to swoon over the scent of my "tobacco plants"
More experienced Cosmos growers please come along and give better advice
that I can.

Tina