The genus Passiflora contains more than 500 species of plants. These vines bear either purple or yellow fruits, known as passion fruit. The mature fruits make an edible snack, while the stems, leaves and flowers are a common source of herbal ingredients. Passiflora cultivars grown for commercial fruit production include "Bali Hai" "Pintado," "Hawaiiana" and "Purple-gold." Although passionflower makes an attractive landscaping vine, it does contain a toxic substance.
The yellow passionflower is a tropical plant, while the purple variety is subtropical and grows in favourable climates within Florida, California and Texas. These plants require a soil pH level between 6.5 and 7.5. The vines reach up to 35 feet tall. Mature vines produce fruit that ripens about 70 to 80 days after pollination. The ripe fruits fall from the vine and require daily gathering to minimise rotting.
Although passionflower teas, extracts and infusions are traditional herbal medicines used to treat anxiety and insomnia, these substances can have adverse effects. The University of Maryland Medical Center advises that consuming passionflower in recommended doses most likely is nontoxic, but should be avoided by anyone pregnant or nursing. Passionflower may increase the effects of certain sedatives, such as alprazolam, zolpidem, amitriptyline and phenytoin. It also can interact with anticoagulants and monoamine oxidase inhibitors, according the medical centre website.
Passionflower fruits contain a cyanogenic glycoside that varies in levels of toxicity. Immature, unripe fruits have the highest levels, while the ripe, wrinkled fruits that fall from the vine have the lowest levels. When ingested, this glycoside, known as passiflorine, acts as a tranquilliser or sedative. The amount of cyanogenic glycoside in the ripe fruits is small enough to be insignificant.
As with all medicinal herbs, do not give herbal preparations from this plant to children unless your doctor recommends it. Although the levels of toxin in ripe fruits are too minimal to cause toxicological concerns, keep unripe fruit out of the reach of children and pets to minimise risk of ingestion. Planting these vines in an area away from children and pets may help relieve concerns about growing these attractive fruit-bearing vines in your landscape.