First of all, they won't be very happy with "decorative red rock" around them. Secondly you are supposed to NOT cut them down and allow the stems to catch leaves and stuff to keep them from dying. And thirdly it's really very late in the season to expect them to get well established before frost. Most likely they won't survive.
To increase the odds, remove the rock and lay down an organic mulch and when frost browns them, pile high with leaves...oh and water very well in the mean time.
Linda C

I usually leave my mums uncut until spring. It helps protect them to let the stems catch leaves, etc.

As far as the particular mums you bought, they may or may not survive the winter. If you recently bought them in bud and/or bloom, they are pretty much mass-produced to be used as a seasonal annuals. However, I always either stick mine in the ground or put the pots in my unheated garage. You never know. I have had several mums come back for me and last for years. If you really want mums as part of a garden design or plan, I would recommend buying them in spring and planting them then. I know off the top of my head that Bluestone sells them in spring.

Good luck!

:)
Dee

I have always had my fall planted mums return the following spring...I do dig a fairly large hole to allow for quick rooting/settling...

Really depends on the mums you purchased and then luck. Leave them stand , do not cut off in spring until you begin to see green around the base. I'm not sure about the rock, I tend to agree the rock around them my not be a good idea. Not too late to plant and get established. I have a 90% return on my mums. I usually get three to five years out of each plant ( even the fall pretties you are beginning to come out in garden centers now) The sooner you put them in the ground, the better your chances and the locations you select to plant them in also can effect the sucess. My oldest mum which was a pretty sent to my father-in-laws funeral was planted in 1993.

I forgot to mention that I don't usually buy my seasonal mums until mid- to late September, and as I've said, I have pretty good luck with them coming back, so maybe yours will have plenty of time to establish, if they are going to.

Dee

Going to just echo the above - it depends.

If I want mums for the perennial beds, I make sure to buy the ones tagged "hardy mums". If you buy the regular potted display mums, it's a crapshoot as to whether they're winter hardy with the odds definitely not in the gardener's favor. Those labelled "hardy mums" generally are hardy (I've personally never bought one that hasn't returned in subsequent seasons).

I don't cut mums back all the way, the general line of thinking being the foliage helps insulate/protect the plants. Sometimes I leave all the foliage, sometimes I cut back about 1/2 way, but I do leave at least 1/2 of the foliage standing over winter.

Mums like very well draining soil, wet feet in winter is a problem and could spell the end of your mums, so choose an appropriate location. Full sun is best, but they'll do fine in partial-shade, too.

I just love garden mums, and they really are very easy to grow if you get the hardy ones.

So many mums on sale now are forced under black cloth so that they'll bloom earlier than nature intended.It's the short days of Autumn approaching signalling the plant to go out of growth mode into flower mode.

That's how mass producers work to get a jump on the competition and an edge on the market share, they provide artificial early nights. It seems to be earlier and earlier every year they start showing up, in full bloom, no less. You used to see them start showing up in September, then August, and now July. To hedge your bets, I'd pick a plant with buds just about to bloom and get'r settled in before the show begins. The less you fool with Mother Nature the better.