My friends,
I believe my marigold [giganticum] takes the price. She is about 7 feet tall and growing. She is just now coming into flower and had been transplanted from a tiny seedling in mid May. I saved her (grand)mother(s) from The Day of The Dead festival in Mexico, in 2017. They were the short standard golden marigolds. I transplanted them into a pot, took mediocre care of them and then they were left to their own devices for about 1 year when I left the country. On my return in May, I cleaned the dead debris from the pots and let whatever was green grow, spreading out the marigold seedlings into 4 pots. They are all tall (at least 4 feet) but she's the tallest.