Tobacco hornworms (the most common hornworm found on tomato plants) have a pink or red horn. Was this hornworm actually eating the buddleia? If so, I don't know what it was, but it was probably traveling to go underground somewhere and make its pupa. It's most likely a pawpaw sphinx - I think I can see the sand papery area on the back of the head. Sherry

I'm thinking that your caterpillar is Menduca rustica, called the Rustic sphinx moth caterpillar and a very close relative to the tobacco and tomato hornworms. The rustic is quite likely to be found on gardenia. Please know that there can be considerable variation in appearance between individuals.

Iris, what kind of plant are those cats ravaging? The Mexican Sweet Herb is very pretty. I guess you could call it a frogfruit, because it's so closely related. It looks like it would make a nice front of the border, or container plant. Do you get many butterflies on the flowers? Do uou know what species of them are the best as host plants. One side of my house is shaded by Oak, and Cottonwood. Grass won't grow there so I have ferns and Hostas, and there's a few shade loving Carex sedge in there too. I noticed a bunch of little plantains in there, that are tiny because of the dry, hot, weather. I'm going to start watering and fertilizing them for the Buckeyes. When I went to harvest a syriaca stalk tonight, I found yet another Monarch cat on it.

Thanks for the response. I actually went to google first and came up empty handed. I even came across the key you linked to and was unsuccessful. Perhaps I should give it another try.