Purple passionflower (Passiflora incarnata) is a fast-growing, evergreen, and tendril-climbing vine. Despite its tropical appearance, this sprawling plant is surprisingly tough (it's the hardiest of all the passionflower species), and the striking, fragrant flowers are attractive to butterflies and other pollinators. This Southeastern U.S. native was cultivated for its orange-yellow edible fruits (called Maypops because of the sound they make when stepped on) by the Indigenous Americans, and they provide a nutritious source of winter food for wildlife.
The foliage provides year-round interest in its hardiness zone. It flowers from June to July and fruits from September to November.
|Common Name||Purple passionflower, Maypops, Wild passion flower, Apricot vine|
|Botanical Name||Passiflora incarnata|
|Plant Type||Herbaceous vine, Perennial|
|Mature Size||Up to 20 ft. tall|
|Sun Exposure||Full sun, Partial shade|
|Soil pH||Neutral, Acidic|
|Bloom Time||Summer, Fall|
|Flower Color||Purple, Pink|
|Hardiness Zones||7-11, USA|
|Native Area||North America|
Purple Passionflower Care
This twining vine is ideal for growing up against trellises, walls, or fences. Because it attaches with tendrils, it won't cause damage to brickwork the way plants with aerial roots, like ivy, can. However, it still produces flowers even if it is sprawling rather than climbing.
If you want to encourage flower and fruit production rather than excess foliage growth, try restricting the growth of the spreading root suckers. Growing it in a container works well in these instances.
Purple passionflowers are highly flammable plants, so it won't be the best choice for growing up against your home in areas at risk of wildfires.
Purple passionflowers thrive in full sun but can also tolerate a part shade position.
Purple passionflowers aren't fussy when it comes to soil and adapt well to most types (including extremely poor soils), providing they are well-drained and moist. It might even get a little out of control in highly fertile soils.
This climbing vine can handle drought conditions, but keep the soil consistently moist for the best chance to appreciate the beautiful blooms. Slow, deep watering at root level is best. Applying a few inches of loose mulch at the roots can help to retain moisture, especially when conditions are dry. Just make sure the mulch doesn't press up against the plant stem.
Temperature and Humidity
These tropical-looking flowers are surprisingly cold-tolerant. Providing your purple passionflower is planted in well-drained soil, the roots should be hardy down to around -5 degrees Fahrenheit. While the top growth dies off in these freezing temperatures, the plant will stay healthy if you mulch the roots. In warmer climates, this evergreen remains woody.
Regular light feeding helps ensure your purple passionflower blooms prolifically. Select a fertilizer that isn't too heavy in nitrogen; otherwise, growth will focus on the green foliage rather than the flowers. Fertilize in the early spring before the emergence of new growth. Once the flowers appear, feeding at least once a month or more through to early fall is ideal for these heavy feeders.
You won't need to prune purple passionflowers regularly. However, if you want to encourage a full, bushy appearance and prevent your climbing vine from looking straggly, it helps to pinch back the plants in their first growing season.
In cooler climates, cutting back the top growth annually is common as the plant is treated as a herbaceous perennial rather than a woody evergreen. Because flowering occurs on new growth, pruning should be done in late winter or early spring to ensure new blooms still appear in abundance later in the spring.
Propagating Purple Passionflowers
It's possible to propagate purple passionflowers via various methods, including taking softwood stem cuttings, tip layering, and growing from seed.
To propagate from stem cuttings, try following the steps below:
- In the spring, select a 6 inch cutting from a young shoot with leaf buds (you can also take woody cuttings in early summer)
- Remove any leaves at the base of the cutting
- Put the base of the cutting into a well-drained potting mix at a depth of around 1 inch
- Moisten the potting mix and cover the pot with plastic with a couple of air holes
- Keep the plant warm, moist, and out of direct, intense sunlight
- It typically takes a few weeks for the cutting to start taking root
- Once the roots have properly taken hold, you can transplant it to its outdoor location
If you want to create a new plant in the same location as the original, you can try propagation by tip layering. This involves bending a stem of the existing plant to the ground, covering it in soil, and waiting to see if a new shoot will develop. Trying this method in late summer or early fall is best, and following the tips below can help maximize the chances of success.
- Before pushing a vine tip into the soil, remove any leaves and nodes for a smooth finish. Foliage buried in the soil can lead to bacterial problems.
- Make a dip in the soil, place the tip into this space, and then cover it over with soil
- You might need to weigh down the tip with a small rock or garden anchor pin to stop it from popping up and losing contact with the soil
- When the tip is well-rooted (it should stay in the ground when you tug on it), it should create another plant in the same place. Alternatively, you can dig it up and detach it from the original plant to transplant it to a different location.
How to Grow Purple Passionflowers From Seed
You can propagate purple passionflowers from seed, although it is a little more tricky than propagating from cuttings, and germination is slow. It typically takes two to three months but can take up to a year. Try following the steps below in late winter or early spring:
- If you are using seeds from an existing plant, these can be taken from the berries when they are soft, shrivelled, and yellow.
- Mature seeds are brown, and the best chance of germination occurs when they are sown immediately after picking
- Clean and then soak the seeds in warm water for 12 to 24 hours. Floating seeds are not viable, and you should discard them.
- Sow on the surface of a damp potting mix
- Put the pot in a plastic bag to seal in the moisture
- Keep the seeds out of direct sunlight while waiting on leaves to appear. Grow lights and a consistently warm temperature during this time can help increase the chance of successful germination.
- When the seedlings are large enough to handle, you can prick them out and put them into individual pots
- Seedlings benefit from being kept in a warm environment for the first winter, before planting them out after the last frost in late spring or early summer
- Harden off the plant for around two weeks before transplanting to the permanent position
- The seeds can be sown directly in their outdoor location if temperatures stay above 55 degrees Fahrenheit
Potting and Repotting Purple Passionflowers
Because purple passionflowers are such heavy feeders, even with fertilizers, your plant will exhaust the nutrients in the pot after a few years. At this point, it's a good idea to repot in a container at least a few inches bigger than the current one. Make sure the pot has good drainage holes and that the medium you use is fertile and well-drained.
Common Pests & Plant Diseases
One of the appeals of the purple passionflower is its moderate resistance to deers, pests, and diseases. However, pests such as scale insects, spiders mites, and whiteflies might be a problem in humid and warm climates. Root rot can also be an issue if your plant is in soil with poor drainage.
How to Get Purple Passionflowers to Bloom
The purple passionflower's exotic, fragrant summer blooms are around 1 to 3 inches wide and typically only bloom for a day. Loose, hanging vines are more likely to produce blooms, so don't try to train your plant too formally. Because they are heavy feeders, if you don't get the nutrient levels right, you might be disappointed by how many blooms appear.
How fast do purple passionflowers grow?
Although they are slow to germinate, purple passionflowers grow vigorously. When conditions are right, these vines can grow as much as 20 feet in a year.
How long do purple passionflowers live?
Purple passionflowers can live up to a decade or more if they get the right care and climate.
Can purple passionflowers grow indoors?
These plants can grow indoors if they get enough sun and warmth, but you shouldn't expect them to flower. The long vines, up to 20 feet, can be unwieldy as an indoor potted plant.