Beginner Gardening: hardy mums - need alot of help please, 1 by HERBIE43

HERBIE43 wrote:
i am not much of a flower person, not for lack of trying, but rather that the deer seem to eat whatever flowers and bulbs i plant.
i went to my local sams club and just could not believe the size of these mums and i had to get some. they were $16.00 dollars each. i bought these two and have them in containers for the moment as my dw is hosting a bbq for her school class of, get this, 1958. they had a reunion last year and now she is having them up here. she wants me to leave the mums in the containers and place them on either side of my front step.
also, i understand that the deer to not bother them.

here is what i need to know

can they be planted in the ground around the last few days of september.
can i use the mix i normally use for my containers (mg potting soil for containers) and put that in the hole i dig for the plants.

the little tag that came with them states do not fertilizer after august and tgrim after the winter

i have no idea what to do, what fertilizer to use and how much (the plants are pretty big) when to fertilize
and do know when or how to trim them back.

would appreciate all the help i can get. thanks alot.

p.s. if it is to late to put them in the ground what can i do with the containers??

sams club sells these every year at this time (beginning of september) and next year i want to buy a bunch cause i have a great place to put them