Hi Amber,
Mums do bloom in spring and summer, but if you want a big bloom this fall, don't let them bloom from now until October. There is a rule of thumb (the month that you stop letting them bloom, but I've forgotten when that is exactly.Just pinch or trim the flower buds off until we near fall. I like the foliage and they are generally compact and healthy plants. I'd give them occasional food, whatever your other plants get and water when it's dry.

I'm sure that others will offer their tips too ;-)

Pam

Amber,
I'm just west of fort worth (also zone 7) and I have mums. I did just like you and they are doing great. I planted them one fall and they came back the next spring. After they were done flowering, I deadheaded them and left them alone. they bloomed again in the fall. This spring they spread quite a bit and are almost done blooming for now. I imagine that they'll bloom again for me in the fall. I've even had to dig some up as they can have some long runners. They spread by underground runners and can pretty soon fill an area. I don't really do much to them other than cut off the spent flowers and clean up the winter deadness. I don't remember if they completely died down or had green the whole year. Mine are on the north side of the house and get some afternoon sun, but there is a tree there too that provides some shade.
Hope this helps.
alison

Hi Pam and Alison.

Thank you for your advice on the mums...

I've been trimming off the old blooms and pretty much letting the foliage do its own thing. Hopefully I will see more blooms this fall!

Pam's comment about trimming/pinching back mums for fuller mounds and more buds--do it up until about July 15 or 20th here the South.

Thanks again for the feedback . . .

I just gave the mums a good top shearing, ridding the top of the plants of the current buds and faded blooms as well. The blooming had recently slowed anyway. I'll be eager to see if they bloom heavily this fall!