This Ivyleaf Morning Glory (Ipomoea hederacea) is winding around some kind of grass (and you're on your own with grasses); note that the stalk on the left is not part of this plant. I'm often asked why plants of the same species are different sizes. Just like animals, access to nutrients is key. Unlike animals, though, plants can't move. Plants have to make it where they are, and some locations are better than others!