Try asters.

My sympathies! It's tough loving a plant that doesn't love you.

Are you talking about the potted plants in the store now, or have you tried some of the really perennial mums sold by nurseries (usually mail order) in the spring? I've found that a couple of spring planted perennial mums do well for me to the point of needing to have chunks ripped out each year to keep them in bounds.

Are you growing in pots or in the ground?

Or as Camps suggested, there are quite a number of plants with fall blooms or fall foliage color to use as alternatives, including asters, Actea (often listed as Cimicifuga)/bugbane, Agastache rupestris/hummingbird mint, Aconitum/monkshood, or Caryopteris/blue mist shrub. There are also bulbs with startlingly spring-like flowers if you want something a bit different: fall-blooming crocus and Colchicum (with the confusing common name of autumn crocus, though they aren't crocus at all.)

I get the plants that are in pots, sold in stores or nurseries around this time of year. I have not seen the perennial ones in the spring, and honestly, I have little luck with the pot ones that it might be worse with the perennial ones.

Yes, every gardener has "those" plants which just do now work for them whatever the reason, in spite of all attempts. I think there was a thread about it recently. Mine is hakonechloa, Japanese forest grass. For all intents and purposes, I should have the perfect environment for growing this, but various attempts over the years have led to a dried shrivelled clump that fades to nothing. And then I go to gardens where there are these huge masses and they say they just spring up with no work and they can hardly control them - and I get that growly feeling inside :-)

What we are saying, even if we didn't say it, is "greenhouse mums" in colder zones rarely winter over well and bloom the following year. These mums are force fed, have their daylight hours manipulated and their roots are a solid mass so that if you threw one it'd break a window.

After a greenhouse mum blooms it doesn't have time to establish a good root system in your garden soil before the ground freezes.

You might find 'perennial garden mums' in spring at local plant sale. Or go to Lazy S Nursery or Bluestone which both have a good mum selection. Order in Spring, plant in spring. I've had good luck getting some large free shrubs on "Freecycle". I've given away big 'you dig them' shrubs there too. I wouldn't hesitate to post on freecycle.

Even if you don't mail order at least look at the selection and see for yourself that there at least 10 perennial mums that are very hardy.

I buy hardy mums and they overwinter fine and grow the following Spring and by this time in Sept. are blooming. The only thing I forget to do is pinch them back early so as to make them bushy and not grow so tall. Every nursery and small Mom and Pop sells mums around here. I tend to buy the small or medium sized potted mums, not the huge ones. Those are beautiful tho.

Schoolhouse, what zone are you? That makes a difference

Every Mum sold are not hardy. I have brought them from my local nursery and they tell you which ones are garden mums.

I prefer the asters they seem to do better and bloom longer for me than Mums.

I gave up on mums years ago, however the Sheffield "daisy" does extremely well for me. Agreeing with some of the comments above,

1. There are quite a few great fall bloomers, some of which should work for you. Asters, goldenrod, Montauk daisy, tricyrtis, chelone, pysostegia (obedient plant), some speedwells (veronica), sedums. Coreopsis and kalimeris will re-bloom if sheared back after flowering. There are some re-blooming irises; 'Immortality' reblooms for me late October into November, but I have to admit I think it looks rather out of place that time of year. Cimicifuga is great, but now that it's been mentioned, I realize mine didn't bloom this year. Nor did the Japanese anemone 'Whirlwind' that usually blooms late summer into October. I'll blame the hot, dry summer.

2. Glad to hear I'm not the only one to have trouble with hakone grass, even though conditions should be right. If this last one doesn't make it, I'll just have to add it to the (thankfully short) list of plants that just don't get along with me: stachys and scabiosa.

Don't forget to look beyond flowers for color; there are lots of shrubs and trees that have outstanding fall color. My latest is a dwarf cultivar of our native oak leaf hydrangea - 'Pee Wee'. Leafs out early, white flowers aging to rose in summer, then fantastic burgundy foliage with some shots of yellow and orange in fall. Winterberry holly's red berries will persist throughout winter. Native witch hazel blooms about November-December here; the Asian varieties bloom late winter/early spring, but some have excellent fall color, and there are dwarf cultivars of both native and Asian varieties.

don't be hard on yourself. I think a lot of times, these fall mums sold by grocery stores, nurseries, etc are not particularly high quality plants. They are not designed to keep, but rather to sell well especially to those grateful summer is over.

I have never had luck with the annuals either! All my neighbors have them and I want to try again so badly but I am not going to buy any more. Not sure what I am doing wrong. I am also zone 5.