...but I heard the real way to know is to chew a leaf and it will be super hot; and I tried and nothing at all. It was just a small leaf and when there was no heat I spat it out (just in case I should have never done that). But now I'm clueless as to what it could be. So anyone have any idea what this is? (Close up on the bottom is the underside of the leaf. Above that the stem; ignore the fat leaf from a vine sneaking in that shot, it's unrelated). I really wanted to find out; because if it was "Smartweed"... that's apparently edible(?) and very "spicy" and that would be useful for me. But I don't want to start frying up things I'm not certain of either. (Also, this is my first post here, so I hope I'm doing this right.).
Welcome, @Zeno. There seem to be around seven different species of plants with the common name smartweed, see Polygonum - Wikipedia. Oh, I think they have been renamed to Persicaria - there are even more species at Persicaria - Wikipedia. Here is a page on pale smartweed. Ontario Weeds: Pale smartweed (gov.on.ca). And Persicaria lapathifolia - Wikipedia, with a photo that looks pretty similar to yours. Another common name for this species is nodding smartweed, which seems apt for your first photo. This isn't the species that has the spicy quality you're after, but it would be in the same buckwheat family genus.
Thank you so much. I really appreciate the information and links. Finding it this year was the first time I ever saw one. I like to try and find out what something is whenever something new appears. My searches to find out more about it when it didn't match the "spicy" description were going nowhere. This helps me a lot to learn more.