Planting and then re-planting wallflowers

I am about to collect about 60 bare rooted wallflowers. Unfortunately the beds where I want to plant them are still occupied by floriferous dahlias and cosmos. They possibly have a few weeks of display left in them. 

Would it be best to put the wallflowers into pots for now or could I put them in a cleared raised bed, which would be the easier option, and replant them some time next month? I’d welcome advice.