I’ve always been surprised that the nursery and landscape industry doesn’t offer more passionflower vines for sales. The vines grow like weeds and are actually considered an invasive pest in some areas. For home gardeners, passionflower vines can be used to produce a quick fence and wall covering design that includes the exotic flowers and tasty fruits.
In Liguria, Italy, where I live, passionflower is a common weed. I see far more of these as wild plants than as vines cultivated in gardens. When my wife and I go hiking around in the woods during the summer, I often find batches of wild passion fruits to munch on. Occasionally, I see passion fruits for sale by the local farmers in the vegetable market downtown. Lots of people here call passion fruits granadillas, which means “little pomegranates” in Spanish because the seeds inside the fruits resemble pomegranate seeds.
There are a number of passionflowers native to the United States; many Native American cultures used these fruit for food, beverages and medicines. Most passionflowers seem to prefer coastal areas or tropical zones, but some of the species do grow as perennials in fairly cold climates. The purple passionflower, Passiflora incarnata, the state flower of Tennessee, is one of the most cold-tolerant species.
The photo here is the Passiflora caerulea, which is called the blue passion flower. This is the species that is essentially wild in Liguria, but I don’t think it is native. The Catholic Church had some influence in the naming of the plants; the symbology concerns the whips, nails, crown of thorns and Holy Grail that are said to be represented in the various flower parts.
The ecology of the passionflower is interestingly complex. The flowers draw some of the largest bees and insects for pollination, and the nectar feeds a lot of different butterflies. The vines often secrete nectar on parts of the stem to attract ants that help combat excessive butterfly eggs and larvae. Some species grow nodules that resemble butterfly eggs, and therefore confuse the butterflies into thinking that that flower is not a good location to place more eggs. A few of the passionflower species are protocarnivorous, meaning that they trap and kill insects, but do not digest them.
For those gardeners who wish to dig a little deeper and plant further than the usual purple-flowered Passiflora edulis offered for sale at retail nurseries, there is a whole rainbow of different flower types to choose from, including reds, oranges, pinks and whites. Passionflowers are easily as exotic as any orchid, but somehow they don’t quite get the same respect. Here’s a link to some nice passionflower photographs.
The parking area at my studio has a volunteer passionflower vine I’ve trained to grow along the fence. It’s already covering the majority of the fence and it brings a nice look to the narrow planting. There are flowers all over the vine, and I can see than some of them have been fertilized and are developing into fruits. Yummy! I can’t wait.