Hi I grew some mums when lived in Indpls.I never cut them back till
spring& I mounded the soil around them& would leave kind of a drainage ditch.I used 9 inches of mulch but it was a airy type stuff and would lay a few evergreen branches over(a snow thing it snows.. dump off lay back.)They do best in full sun.
Liveing in the south my mums behave different.They bloom in
spring& fall & in july I cut them back& root what I cut off and most of it takes root and thats with no rooting stuff.I just shove a woody stem 2-3 inches in a pot of potting mix and keep moist and shaded and in fall set those out.I have yellow ,bronze,white& a small start of some burgandy.Its best to buy them with lots of buds unopened so you will have a long bloom time& most the store bought ones may have been forced budded so you may not know their actual bloom time till the following grow season.they have early/mid& late bloomers. you would LOVE this place.It shows the types of mums& they are reasonably priced.
http://www.kingsmums.com/