Passiflora caerulea, more commonly known as the blue passion flower or "Constance Elliott," is a twining vine native to the South American countries of Brazil, Argentina, Paraguay and Uruguay. Prized for its fragrant, exotic-looking flowers, Passiflora caerulea can grow up to 9 metres (30 feet) long and looks lovely when coiled around fences, trellises, arbors and pergolas. Grow Passiflora caerulea in a sheltered, sunny spot outdoors.
Plant Passiflora caerulea in a sunny spot that receives six or more hours of direct sunlight per day and offers rich, well-draining soil. Provide your Passiflora caerulea with extra protection from cold winter weather by planting it against a south-facing brick wall or similar support. For best results, plant the Passiflora caerulea at the same height it was growing in its nursery container.
Water your Passiflora caerulea deeply after planting to ensure that the soil around the plant's roots is thoroughly moistened. Continue to deeply water Passiflora caerulea once or twice a week to prevent the soil from drying out. Reduce the frequency of watering to just once every two weeks during the cold winter months.
Fertilise Passiflora caerulea regularly to ensure healthy growth throughout the growing season. Feed your Passiflora caerulea vine with a half-strength application of a balanced, liquid plant fertiliser once a month to provide the vine with a steady influx of nutrients. Follow the application instructions on your fertiliser product.
Spray your Passiflora caerulea vine with water from a spray bottle two or three times a week to increase the humidity around your vine. Note that this is especially important during hot, dry summers. Moisten your vine with the water from the spray bottle, but ensure that your Passiflora caerulea has access to well-circulating airflow or you increase the risk that your vine will contract a fungal disease.
Prune Passiflora caerulea in the early spring to ensure healthy, vigorous vine growth throughout the growing season. Cut the stems of the vine back by one-third using sharpened and sterilised pruning shears. Cut approximately half of the stems all the way back to the base of the vine to encourage rapid, healthy regrowth.
Plant your Passiflora caerulea near an arbor, trellis, fence or pergola if you are unable to plant it near a brick wall support.
Passiflora caerulea are susceptible to infestation by nematodes (roundworms). Treat your blue passion flower vine with a garden insecticide product, if you see signs of infestation.