Does cosmos self-seed in UK?

[rootball]

Hi Everyone

I have grown Cosmos in my garden for many years, one of my favourite summer flowers.

I have read that they self-seed in the UK, for me they never have done so.

Does anyone here have experience of them self-seeding in the garden?

I'm just interested to know if they do.

Thanks,
R

[mothhawk]

I always dead-head mine to keep them flowering so never have any with mature seed, but as they are half-hardy the slightest touch of frost will kill the foliage, and being annuals, once the foliage is dead, that's it.

[mothhawk]

I guess the seed itself may be frost hardy, so if it drops on the ground and doesn't try to germinate before mid May, they would survive. But since most of the UK can have frosts as late as late May to early June, the seedling survival chances are probably low.

[Peanut]

Nope, they have never self seeded for me.

[bramble]

No, I grow cosmos every year...never had any self seed.

[Containergardener]

Not me either. They're lucky to get through the frosts here.

[JoaoLeaftide]

Never had them self-seed here either. I think the seeds need to drop and get enough cold/wet over winter to stratify, but by the time spring comes any seedlings that do try tend to get caught by a late frost. Not worth relying on — just much easier to sow fresh each year.

[Nicos]

We get very cold winters in Normandy….I left the last few flowers to seed last autumn in the gravel driveway…and they were growing by early April.
When we came back 4 weeks later they were looking nicely established - so we transferred them into a pot…where they promptly died
They were in gravel on the north side of the house, so I’m thinking they were well protected roots.
So yes, I’ve had them self seed, but I think they need protection of some sort