Perhaps planted too late or in too much shade. Try south-facing aspect, maybe plant deep and mulch heavily. Avoid heavy soil.

Should bloom until frost, you may get a fair bit of mileage out of it yet. May not freeze until Halloween or later, depending on how far out you are.

Thanks bboy, this little guy is facing south. I thought he was a goner because there was also no foliage until about 3wks ago. I will try more mulch this yr that may help. Puppy3

I thought my chocolate cosmos hadn't come up at all and must have succumbed to winter so I dug it out only to find that the slugs were keeping it mowed down. I replanted it and baited for slugs and it grew in spite of them.

Last winter I lifted the tubers, potted them up and put them in a sheltered area. Because slugs weren't an issue they grew and bloomed much earlier this year.