Passiflora Caerulea Guide: How to Grow Blue Passionflower

Passiflora caerulea is a perennial vine native to South America and is part of the passionflower family (Passifloraceae). This fast-growing vining plant sprouts long, twining tendrils with lobed leaves and showy flowers that have white or blue sepals and white, purple, and blue filaments. It also bears egg-shaped and bright orange fruits. Other common names for passiflora caerulea include blue crown passionflower, blue passionflower, or common passionflower.

Blue passionflower is an especially cold-hardy passionflower vine, capable of withstanding freezing temperatures. It has a spread of three to six feet, with the ability to grow up to thirty feet through its vines (with as much as ten to fifteen feet of growth in a single season). The flowers of these fragrant climbing plants attract beneficial pollinators such as butterflies, bees, and birds.

Plant blue passionflower vine outside between mid-spring and fall, depending on the climate in your region. Blue passionflowers will bloom between early summer and early fall, producing fruit between early and mid-fall. You can also plant blue passionflower indoors year-round. Keep in mind that blue passionflower prefers climates endemic to USDA hardiness zones six through nine.

Blue passionflower grows from both seeds and propagation from stem cuttings. Blue passionflower can germinate easily from seeds in as little as two months. Here is a brief overview of how to grow passionflowers from seed at home.

1. 1. Collect your seeds. If you’re harvesting seeds from a passionfruit to grow new plants, wait until the fruit is completely ripe. Cut the fruit open and collect, wash, and dry the seeds. You can also purchase blue passionflower seeds from a nursery.
2. 2. Soak your seeds. Soak your seeds in warm water overnight to jump-start the germination process. You can also lightly scarify your seeds by rubbing them with sandpaper. Take care not to damage your seeds if you want to scarify them. Discard any seeds that float to the top of your water bath.
3. 3. Germinate your seeds. Fill a small container with damp potting mix and place your seeds on the surface of the soil. The seeds will need plenty of light to germinate properly, so do not bury or cover them. Wrap the entire container in a clear plastic bag to retain moisture and place the wrapped container in a warm place out of direct sunlight.
4. 4. Check for sprouts. Your seeds should begin to germinate into seedlings within two months. Introduce your plant to full sun once your sprouts are beginning to show real leaves. Move your sprouts into full sun for a little bit more time each day.
5. 5. Repot your seedlings. Your sprouts are ready for repotting once they have several sets of leaves. Choose a location in your garden that gets either full sun or partial shade, preferably against something like a fence or trellis for your passionflower vines to climb. Prepare the soil in a large pot or directly in the ground by digging it and testing it for drainage. Carefully dig up your plants from the growing tray and plant them in your new location. Water your seedlings deeply straight away.

Passionflowers are relatively easy to care for during their growing season, but there are a few things you can do to help them get established. Follow these easy care tips to help your blue passionflowers thrive.

1. 1. Avoid overwatering. Blue passionflowers have a powerful root system that helps them survive dry or difficult climates. Water your blue passionflowers infrequently—once every two weeks—to encourage their roots to seek out moisture deep beneath the ground. This keeps them hardy and nourished, even in adverse climates. However, if you live in a particularly hot climate, you may need to water your plant more frequently.
2. 2. Overwinter. Protect your passionflower roots during the colder months so the plant doesn’t completely die off. Spread a layer of mulch around the base of your passionflower roots to protect its root system from frost until early spring.
3. 3. Prune every year. Blue passionflower vines can grow fifteen feet or more per year, so you should prune them annually. In late winter and early spring (before growth restarts), prune your passionflower vine and deadhead (or pinch away) spent blooms plant to encourage new growth for the following growing season.
4. 4. Beware of pests. Passionflowers are susceptible to infestations from whiteflies, spider mites, and scale, all of which you can control with an insecticide.
5. 5. Provide support. Use a trellis or nearby fencing to train your vines and keep them off the ground. A trellis is a structure that provides support for climbing, crawling, or vining plants to grow upwards. Trellising your vines encourages air circulation and keeps your plant away from harmful ground pests.

The fruit of the blue passionflower plant (also called passion fruit) will fall to the ground when it is ripe; however, eating this type of passion fruit is not recommended. The egg-shaped, orange fruit of this passionflower cultivar is not as tart and/or sweet as the main passion fruit cultivars. In fact, the fruit of the P. caerulea has a bland and/or unpleasant flavor, especially when you eat it raw. It can also cause gestational issues if consumed underripe. Additionally, all the other parts of the plant contain toxic cyanide and can be harmful to humans, horses, dogs, and cats.

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