The genus Passiflora contains over 400 species, so the common name Passion Flower can be a bit confusing. To muddle matters further, most are vines, but some are shrubs, annuals, perennials and even trees. What they all share are exotic flowers that only remain open for about 1 day. They have a wide, flat petal base with several rings of filaments in the center which surround a stalk of sorts, that holds up the ovary and stamens. Although passion flowers are native in many regions of the southern U.S., they can become a nuisance, to the point of being invasive. Check with your local Cooperative Extension or DEC to see if you should avoid passion flowers altogether or if certain species are preferable. A lot of gardeners prefer to grow their passion flowers in containers. Passion flower grows quite happily in a pot and you have the convenience of being able to move it to a sunnier site or even bring it indoors for the winter. Plus, it limits the spreading by rhizomes.