Lavender Wreaths

I am planning on ordering two plug trays of lavender but I would like some assistance in which kinds to get.
I want to be able to dry them for wreaths. They will be used as a border - one in front of the other.
Any suggestions on varieties??

Since you live in Iowa your choices are a bit limited. Northern Iowa is in Zone 4 where only the hardiest lavenders will survive the winter in a sheltered position with generous winter mulch. Southern Iowa is in Zone 5 and there all but the Lady lavender of the English lavenders should make it through the winter as well as Grosso and Provence Lavender. Winter mulch in Southern Iowa as well.
As a suggestion you could try the 45 centimeter Munstead lavender in the back row and plant the slightly shorter Rosea or the Jean Davis lavender in front of it. It will give maximum hardiness and maximum colour contrast.