Cosmos question(s)

A colleague has kindly given me a cosmos, 'Sonata Pink' which he's grown - he tells me its perennial and will ultimately be about 2' tall, although its pretty much that size already. I'm happy for it to be taller than 2' but most of the information I can find on cosmos says 'grow from seed'.

Before I plant it therefore, my question(s) is/are:

Is this really a perennial?
How should I care for it?
Should I cut it down? If so, when?
How can I ultimately propagate it?

 

No... it's an annual
Not much really.. you could dead head the finished flowers.
It will die at sometime in the autumn.... pull the whole thiing out when it looks horrid
It's easy from seed next spring.

 

Thank you Quercus - that's pretty much what I thought.

It's in flower now, so I shall enjoy it while I can (perhaps it'll seed for me).

 

There are short and tall varieties. Mine grow to about 4 feet.

As well as being an annual it is also tender. So sow the seeds later (like April) or even 1st May, because if you put it outside when there is still cold weather it can sulk and never really recover.

In a good warm year (I am not sure that this year qualifies) it will continue to grow and flower until November.

 

It's an annual Fidgetsmum.
Keep dead heading the flowers and it will keep flowering until the first frost or when it runs out of light in Novenber.
If you want to get some seed for next year then let a couple of flowers go to seed, cut them, dry them and store the seeds in a brown envelope to keep dry.
Replant them next April or May.

 

I grew Cosmos for the first time this year, i got 2 packets (1 was free) ,I sowed them in April and they came up lovely sturdy little plants, I ended up with about 100 of them , i gave some away and planted the rest round my front borders in clumps of 4/5 plants together.
They have thrived through the warm damp summer to the extent they look like 3ft flowering fir trees.
I will start letting them go to seed now and not plant so many next year.

 

I'd agree there. I bought some of them in a GC as bedding plants about that time, planted them out in early May. They did ok for a bit, but not nearly as good as Pam's seem to have and now there's no sign of them.

 

SussexG - I picked up that tip from Christopher Lloyd's writings. It applies to any tender annual, such as Cosmos, Cleome, Tithonia etc. He recommends sowing on 1st of May, if you can't proctect the young plants in a greenhouse. If you normally sow on 1st March, 1st May sounds like 8 weeks later. But he said that the light levels are so much higher in May and June than March and April, that the plants catch up very quickly with earlier sowings and are probably only 2 weeks later in reality.

The other point was that if tender plants get hit by cold, not just freezing weather, they can sulk and do very little all season. I put some out too early once and they did just that - nothing.