Posted: 15/03/2014 at 09:59
Nothing to lose except seed. I'd start a few of each in pots at the same time, then you can plant them later if needed.
Don't forget that a lot of the seeds sold as wild flower mixes, poppies, cornflowers, corncockles etc, are not grassland plants. They're arable land plants that grow in turned soil alongside the cereal crops