Alliums and daffs in pots

I've planted some of the above in plastic pots which I was going to sink in the ground after new year. They've got roots coming out the bottom already! So shall I sink them in the ground now or plant them out?
Didn't really want to plant them out as they're going in a bed with a residual bindweed problem and it's also where I'm planting dahlias again.

 

Could you put them into a larger pot?