On Sun, 29 Aug 2010 16:08:10 +0100, Syke
wrote:

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?

I grow cosmos every year and find that their eventual height is often
down to what I ultimately plant them in; timing of planting doesn't
make any difference unless you plant out too early and get a late
frost. This year, mine have all been about 2-3 feet high but last
year, some planted in fresh compost in tubs grew to about 4 feet, some
planted in an "old" border were about 2 feet high and those planted in
a "refreshed" border - one I had cleared out, dug in manure and all
that and then replanted, produced really bushy plants, covered in
blooms and over 4 feet high.

I would always treat cosmos as a middle of the border plant, not a
front one. That said, this year I have 2 foot tall impatiens and all
my marigolds produced one bloom and then keeled over and snuffed it.
Gardening is like that - enjoy the surprises and put the failures down
to the idiots at the Met Office who can never get the forecast right.