it is a prolific seeder and produces dandelion like clocks so the seeds carry a long distance. It also has a long tap root [edible as white salsify] and if they grow where you dont want them they are a nuisance to dig out. The flowers tend to close by mid day. One common name is 'Jack go to bed by noon' .

I do have it and it is a biennial but not sure it would be suitable for a small garden. See what others say.

I would tend to agree with that. It is a seed weed of the first order.

Thank you. I thought that might be the case. I shall just admire them growing alongside the main road.
Thanks again.