Passiflora, commonly referred to as the passion flower, is a tropical vine with more than 400 species variations. Growing in an array of colors, these vigorous climbers are invasive and often viewed as weeds. Passiflora is predominantly evergreen; however, deciduous variations (passiflora incarnata) do exist and are often referred to as the maypop. To grow passiflora from seed, begin the seeds indoors before transplanting them outdoors in mid-spring.
Select a planting location for the seeds in the late fall or early winter. Choose a fertile, well-drained location that provides at least six to eight hours of full to partial sunlight. Select a planting area where the vines can climb such as a trellis, patio or pool.
Prepare the passiflora seeds by soaking them in warm water for one full day. Mix nutrient rich soil with warm water so that the soil is moist but not wet. Place the soil in a porous, well-draining planting flat. Level the soil off at the top of the flat's edges and gently press the soil down. Use your finger to create shallow grooves in the surface of the flat that are approximately 1 inch apart and no more than ¼ inch deep.
Place the seeds in the furrows and gently brush a light layer of soil over the seeds with your finger. Label the flat with the sowing date and passiflora species. Place the flat in a pan and fill the pan with warm water until the water comes about halfway up the flat.
Allow the flat to rest in the water-filled tray until the top layer of soil is moist. Remove the flat from the water and allow the flat to rest until the water no longer drains from the bottom. Promote a tropical environment by covering the flat with clear plastic, which allows the light to penetrate.
Place the newly planted seeds in a warm, indoor location that receives three to four hours of partially shaded sunlight. Avoid direct sunlight to prevent seedling damage. Remove the plastic when sprouting begins.
Move the newly sprouted passiflora to a location that receives at least three hours of partially shaded to full sunlight each day. Increase the sunlight intensity an additional hour each day until the plants reach six to eight hours of partially shaded to full sunlight each day
Plant the passiflora outside in the mid-spring after the final frost. Dig a shallow hole for each passiflora seedling. Make the hole no deeper or wider than the root of the passiflora's root system. Position the passiflora in the center of the hole and fill the hole with the soil. Gently press the soil around the passiflora to secure it in a upright position.
Water the passiflora regularly, but do not overwater. Apply a layer of mulch around the base of the passiflora to promote good moisture levels. Fertilize the passiflora with a granular, slow-release fertilizer in the early spring and late fall. Use a well-balanced fertilizer for more green vines and fertilizer with lower amounts of nitrogen for more flowers.