Melon Vine With Yellow Flowers . Grow melons in full sun with plenty of air circulation. I have a vine that i originally thought was watermelon growing from my seeds from last year. Cucurbitaceae plant family Britannica from www.britannica.com Bitter gourd or bitter melon flowers can be gorgeous when vines are in bloom. Not all plants within a field initially show symptoms (image 2). The ovary is up to 20 mm long, pale green with numerous minute, dark green fleshy spines, the corolla is yellow, 8.