Growing Passion Flower Vines on Fences: A Complete Guide for Stunning Results

Common names: passion fruit (English), parcha and maracuyá (Spanish), maracujá (Portuguese), lilikoi (Hawaiian), buah susu (Malya), linmangkon (Thailand), chum bap (Vietnamese). Figure 1 shows the flower.

Distribution: Various species and cultivars of passion fruit are grown throughout tropical and subtropical areas of the world.

Importance: Estimated worldwide annual passion fruit production is about 1.5 million metric tons, with Brazil as the leading passion fruit producer in the world (Altendorf 2018). Other major producers include Colombia, Peru, Ecuador, Australia, New Zealand, Indonesia, and some African countries. In the United States, passion fruit is grown commercially in Florida, Hawaii, Puerto Rico, and California.

History of Passion Fruit

The first European report of passion fruit was by Cieza de León in 1553 when he was a civil servant in Colombia (Ulmer and MacDougal 2004). He called the fruit “granadilla” (small pomegranates), which was potentially Passiflora ligularis. In 1569, Nicolás Monardes, a physician in Spain, associated the passion flower morphology with the crucifixion of Christ. Subsequently, the passion fruit flower was used by early missionaries in Brazil as an illustrative aid in an effort to convert the indigenous population to Christianity. Specifically, it was referred to as “flower of the five wounds” to represent Christs crucifixion. The symbolism endured such that Carl Linnaeus established the scientific name of the genus Passiflora (Latin for passion flower) in 1737 (Kugler and King 2004).

Passion fruit is a short-lived evergreen perennial vine that produces an aromatic and tropical-tasting fruit. The most commonly cultivated types in the United States are the purple passion fruit (Passiflora edulis) and, to a lesser extent, the yellow passion fruit (known as P. edulis flavicarpa). Currently evidence suggests P. edulis and P. edulis f. flavicarpa are morphologically and genetically of the same species, and therefore P. edulis is the preferred genus species designation (Bernacci et al. 2008; Silva and Santos 2020). P. edulis is native to the regions of Brazil, Paraguay, and northern Argentina and is grown worldwide in suitable climates (Ulmer and MacDougal 2004). There are more than 500 species within the Passiflora genus, while only a small number produce edible fruit. Most are tendril-bearing vines, and many have ornamental value.

While P. edulis is most commonly grown, there are other species within the Passiflora genus that are of agricultural significance: sweet passion fruit (P. alata) has yellow to orange fruit; sweet granadilla (P. ligularis) has an orange shell when ripe; water lemon (P. laurifolia) has yellow or orange fruit and coconut flavor notes; sweet calabash (P. maliformis) has round yellow-brown fruit; and giant granadilla (P. quadrangularis) has greenish-yellow fruit up to 8 inches long. P. incarnata, commonly called maypop or “passion flower” (not to be confused with P. edulis), is the most cold-hardy species native to the southern United States, and it has yellow to green fruit that are insipid to slightly sweet.

Passion fruit are adapted to tropical and semitropical climates, such as Florida. USDA hardiness zones 9b and above are suggested for P. edulis. Under favorable conditions, new plants grow vigorously and typically begin producing flowers and fruit within a year of planting (Figure 2). The life span of a productive passion fruit vine is typically about three to four years, though they may occasionally live longer. The true purple passion fruit is said to be adapted to high-elevation environments in the tropics. In contrast, yellow types and purple-yellow hybrids are considered better adapted to lower, warmer elevations. Passion fruit prefer well-drained soil and have shallow root systems. As such, the vines have limited drought and flood tolerance (Queensland Department of Agriculture and Fisheries 2016). Mature vines with dense foliage may tolerate temperatures slightly below freezing with some loss of foliage, though exposure to temperatures in the mid-20s (degrees Fahrenheit) may result in entire aboveground vine death that may not resprout from the underground tissue (Campbell et al. 1977).

Passion fruit is not listed on either the USDA Florida noxious weeds list or the Florida Exotic Pest Plant Councils list of Invasive Plant Species.

Growth Habit: Passion fruit grow as perennial lianas or woody vines that grow to great length, often covering the tops of mature trees when growing naturally (Figure 3). While mature vines total length can exceed 100 ft, they can also grow more than 35 ft in a single year. As new growth emerges from the tips of vines, flower buds emerge along with young leaves and tendrils. The vines tendrils help it climb and remain secure as they wrap around objects they come in contact with. Vines that are in shade or partial shade typically drop their leaves.

Leaf Morphology: Passion fruit leaves typically grow up to 8 inches long, and they are green, glossy on top, paler and dull underneath, single, and alternate. Passion fruit exhibit heteroblasty, which means there is a noticeable difference and transition in leaf shape: the leaves of young seedlings are oval-shaped, while adult leaves are deeply lobed with two indentations and finely toothed (Figure 4). Intermediate leaves can have both adult and young traits. At the base of each leaf are extrafloral nectaries (Figure 5), which secrete a sugary solution that attracts nectar-seeking insects, such as ants and bees.

Flower Characteristics and Morphology: Passion fruit flowers are 2½–3 inches wide, are slightly fragrant, and face outward, away from the plant (Figure 6 and 7). The flowers are perfect, containing both male and female parts. The flower structure (Figure 8) is pentamerous with 5 petals, 5 sepals, and 5 anthers. Below the three-pointed stigma is the ovum, which will grow into the passion fruit if adequately pollinated. Below the anther is the operculum, which contains nectar that attracts nectar-feeding insects. Extending out from the operculum are many coronal filaments, which are dark purple nearest the center and turn white as they extend outward. Underneath the corona filaments are the 5 petals and 5 sepals. The sepals, which are under the petals, can be distinguished from petals by the presence of a green tip. The large carpenter bee (Xylocopa spp.), which has a similar appearance to a bumblebee (Figure 9), is the most effective insect for pollinating passion fruit. Other bees and nectar-feeding insects can also aid in pollen transfer from one flower to another. Some purple varieties can be self-pollinated, while yellow varieties are not considered capable of self-pollinating, and hybrids vary in their self-compatibility.

Fruit Morphology: Flowers emerge on new growth and will only produce a fruit if pollinated. The quantity of pulp is determined largely by pollination quality. The fruit originates from the ovum of the flower. As the immature green fruit grows, remnants of the flower sepals and petals may remain (Figure 10). Mature fruit ripen into colors ranging from dark purple or burgundy to yellow (Figure 11). The pepo-type rind surrounds a white pith, which together is botanically a berry filled with pulp covering black seeds. The pulp is composed of membranous sacs, called arils, filled with orange-yellow juice (Figure 12). Mature fruit are typically about 2½–3 inches long and about 2¼ inches wide and may be egg-shaped to round.

There are numerous local selections of passion fruit in Florida, with most of them being hybrids between yellow and purple types (e.g., cultivars Panama Red, Purple Possum, and Bounty). Commercial producers have typically selected their own superior seedlings for scions that they vegetatively propagate via rooted cuttings or that they graft onto a rootstock. A passion fruit cultivar can be evaluated for characteristics that include fruit size, appearance, disease resistance, quantity of pulp or juice, pulp-to-skin ratio, flavor, sugar and acid concentration, and aromatic qualities. There is limited information about cultivar characteristics, although what is known is listed below.

A seedling selection from Possum Trot Nursery is the most widely grown and propagated cultivar in south Florida (Figure 14). The flowers are self-compatible. The peel has a medium-dark purple color with numerous light dots covering the surface. Fruit are 2.5 to 3.5 inches long and ~2 inches in diameter. The fruit have a pleasant aroma and the juice has a sweet, moderately strong flavor. Flowering to harvest takes 70–75 days.

As the name suggests, Panama Red has a red peel color when ripe. It is oval in shape. It is likely selected by Australian producers for higher yields. The fruit can be larger than Possum Purple and have a similar flavor profile.

The Sweet Sunrise variety is a yellow type with fruit about the size of a baseball. It is currently sold by nurseries in southern Florida (Figure 15).

A seedling selected by William Whitman, a long-time and well-known tropical fruit enthusiast intimately involved in tropical fruit culture in south Florida (Figure 16).

Additional cultivars from Hawaii and Australia may not be currently available in south Florida. Those of interest include Australian Purple, Dons Choice, Frederick, McGuffy, Misty Gem, Nellie Kelly, Panama, Pandora, Pink Cheek, Pratt Hybrid, Red Flemenco, Red Rover, Sweetheart, Tas Black, Toms Special, and Waimanalo Selection. Yellow cultivars include Kapoho Selection, Mikes Choice, Panama Gold, Sevcik Selection, University Round Selection, University Selection No. B-74, Whitman, and Yee Selection.

Propagation: Passion fruit may be propagated from cuttings, micropropagation, or fresh seed. Only disease-free planting material should be used, especially due to the presence of persistent viruses. If propagated from seeds, they should be as fresh as possible and kept in warm, humid conditions to induce germination. While fresh seeds will have a higher germination rate than older seeds, they still have relatively low germination rates compared to other crops. Germination can be aided by scarifying the seed coat, nicking the edge of the seed using a sharp blade, and soaking overnight in water. Seeds can be sown in flats or pots of clean soil or growing media and kept moist. High-humidity conditions are best, which can be aided by covering the growing containers with plastic or humidity domes. If kept warm (about 85°F), seeds typically germinate in a week and a half to three weeks. After germination, young plants should be kept in partial shade rather than direct sunlight, which will burn the young plants. Transfer young plants from a partial shade to partial sun for several days prior to planting in full sun.

Passion fruit can be propagated by cuttings from productive healthy plants, selected carefully to avoid propagating virus-infected plants (Figure 17). This can be done by cutting off a portion of a healthy vine with active foliage. To increase success, use at least two nodes; up to four can be included per cutting. Remove all but the top leaf, making note of which end is the bottom (i.e., by the direction of vine growth). The bottom of the cutting can be dipped in a rooting hormone and then planted about 2–4 inches deep in clean growing media. It should be kept moist (with humidity domes, plastic bags, or intermittent misting) in indirect light and provided with regular moisture to the soil/growing media. Under optimal conditions, cuttings may be ready for planting in three or four months. Cuttings should be kept insect-free to reduce the likelihood of viral infections.

Grafting: Purple passion fruit can be grafted onto a yellow passion fruit rootstock in an effort to reduce disease problems that affect the root system of susceptible cultivars. Seedlings of both stock and scion plants should be about 18 inches long and have a stem diameter of approximately ¼ inch when selected for grafting. Scions should be about 3–4 inches long and contain at least 2 nodes when cut for the graft. The stock should be cut off 10–12 inches above the soil line. Several methods of grafting can be accomplished using a cleft, including whip-and-tongue, saddle, and veneer grafts. The most important aspect of grafting is to align the vascular cambia and hold the graft firmly in place by wrapping with parafilm or grafting tape. Keep the grafted plant watered in a warm, indirect-light location for 10–14 days or until the union takes. The wrapping can be removed when the graft has fully healed.

Location: Passion fruit grow best in full sun or a location where they can reach full sun after climbing. Passion fruit vines should be planted in well-drained soils and will tolerate near-neutral to alkaline (pH 6­–7.5) conditions, but slightly acid soils are best.

Planting, infrastructure, and irrigation: In areas with potentially freezing or cold temperatures (<50°F), young plants may be planted in early spring when the chance of frost is over. In areas with warm to hot temperatures, plants may be planted anytime (temperatures <90°F) as long as irrigation is available during dry periods.

For home landscape plantings, a simple but strong fence or trellis that can withstand high winds when covered with a vine may be used. For commercial production, there are numerous trellis designs and configurations. A common method is a vertical trellis with rows spaced 10 to 15 feet apart. Spacing between plants in the row varies between 6 and 10 ft. Rows should be planted north-south to maximize exposure to sunlight. Ground cover, plastic mulch, or conventional mulch can be used to suppress weeds and maintain soil moisture. An alternative to planting directly into native soil is to use grow bags, which allow for custom-blended media that is disease- and nematode-free. Typically, these container-grown plants are placed on a stand (e.g., cinderblocks) to facilitate drainage and avoid direct contact with the soil. In home landscapes, passion fruit vines may be irrigated with a small low-aspect sprinkler or with installation of a drip system. It is helpful but not required to have timers programmable with climate information and a rain gauge to manage the system so as to minimize watering frequency and quantity.

Commercial plantings use drip lines under plastic mulch or microsprinkler irrigation to minimize water usage and maintain maximum plant productivity. Passion fruit need small but frequent irrigation to ensure that adequate soil moisture is maintained, though not saturated. Soil moisture probes (e.g., tensiometers, capacitance probes) and weather monitoring will improve irrigation scheduling, minimize irrigation rates, and reduce the chance of leaching water and nutrients below the root zone.

Training and Pruning: After new vines have been planted, they should be trained along trellising wires. Afterward, the vines will naturally attach to anything the tendrils can wrap around (Figure 18 and 19). Depending upon the trellis design, vines should be trained to grow in a manner that maximizes the canopy surface area. An option is a “curtain” training system, in which one main stem reaches to the top support wire, with vines spreading horizontally and then drooping down like a curtain to fill in the open space below. Vines should be pruned in late winter when they are not actively growing. Use a 10% bleach solution or quaternary ammonium to disinfect cutting tools between each plant to avoid spreading disease. Over time, if left unmanaged, the new vine growth may become dense and cover older vine growth that loses its leaves, forming a thatch-like canopy composed of dead leaves. This can be a source of fungal diseases that negatively affect new leaves and fruit quality. Vines can be pruned back to the main vine or healthy branches from the main vine. All dead and weak stems should be pruned out and pruned back to vigorous stems so that they can resume healthy, active growth in early spring. A good time to make the first fertilizer application is after pruning.

Cold Stress: Optimum temperatures for growth and production vary by passion fruit species and type (Menzel and Simpson 1994). In general, temperatures between ~65°F and 90°F are best for vine growth and fruit production; temperatures outside this range may result in reduced growth, flowering, pollen viability, and fruit production. Mature vines with adequate foliage may tolerate temperatures several degrees below freezing but may be killed to the ground with prolonged exposure to freezing (32°F) and subfreezing (low to mid 20s) temperatures (Campbell et al. 1977). Passion fruit vines may also experience chilling injury when temperatures are below ~59°F but above 32°F (Menzel and Simpson 1994). Experience with cold protection of vines suggests that high-insulation wraps (e.g., high R-value fiberglass batting insulation) wrapped around the base of the vine may protect this area from freeze damage; new shoots would grow from this area post-freeze event. Insulating wraps should be removed post-freeze event.

A properly designed high-water-volume irrigation system may protect vines from freezing. Typically, high-volume 360° rotating sprinklers placed above the trellis at a spacing to allow for complete water coverage of the vines are used and have successfully protected vines during freeze events in south Florida (J. H. Crane, personal communication). The systems need to be properly installed and maintained, turned on when field temperatures reach ~36°F, and left on until wet bulb temperatures reach above 32°F the next day. Please contact your local UF/IFAS Extension agent for more information.

Drought Stress: Passion fruit vines and fruit production are sensitive to dry soil conditions. Drought stress results in reduced passion fruit vine growth, flowering, fruit set, and fruit size (Menzel and Simpson 1994; Turner et al. 1996). Recent research has shown that drought conditions also makes plants more susceptible to the soilborne diseases caused by Fusarium fungal species (Lima et al. 2019). Severe drought stress results in defoliation, fruit drop, and vine death.

Fertilizer Guidance: During the first year, a young vine should be fertilized to encourage maximum growth of the roots and vines (Table 1). Maximum fruit production usually begins after a full year of growth. Common fertilizers, such as 10-10-10 or 8-3-9, may provide adequate nutrients such as nitrogen, phosphorus, and potassium. It is important to also provide secondary nutrients and micronutrients to maximize plant health and fruit quality. Secondary nutrients include magnesium and sulfur, and micronutrients include boron, nickel, manganese, copper, zinc, and iron. Nutrients may be applied either as fertigation (liquid fertilizer applied through irrigation lines), as a granular fertilizer, or via foliar feeding. If granular fertilizer is used, small amounts (0.25 lb/plant to 1 lb/plant) should be made from late winter through fall on 4- to 6-week intervals (Table 1). These intervals can last through July in northern Florida, while they can continue through October in southern Florida. For vines growing in high-pH soils (>7), secondary nutrients and micronutrients may be applied to foliage or in chelated form to the soil. Chelated iron applications are important for vines growing in high-pH calcareous soils. A chelate such as Sequestrene® 138 (6% Fe-EDDHA) is a good choice; mix the powder with water and drench near the base of the plants 2 to 4 times per year. After the first year of growth, the amount of nitrogen fertilizer should be substantially reduced to facilitate flowering rather than excessive vegetative growth.

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