Passiflora caerulea L.

Perennial vine commonly to c. 5 m long, with simple axillary tendrils, glabrous. Stem subangular, striate, grooved. Stipules reniform, clasping, attached near middle of side, 1–2 cm long, 0.5–1 cm wide, with dentate to subentire margin. Leaves alternate, palmately 5-lobed, occasionally 3, 7, or 9-lobed for ⅔ or more of length; lobes widest in lower half, linear-oblong to broadly-ovate-oblong, acute, obtuse or emarginate, each with a single main vein; lamina 5–16 cm long, 6–18 cm wide, with 2–4 glands in the sinuses, base cordate, margin entire; petiole 1.5–4 cm long, with 2–4 (–6) stalked glands (c. 0.5 mm long) usually near middle. Flowers bisexual, borne singly in leaf axils, (6–) 7–9 (–10) cm diam.; pedicels 3–7 cm long; bracts 3, borne close to flower base and involucral, broadly ovate to ovate-oblong, 1.5–2.5 cm long, 1–1.5 cm wide, entire, free. Sepals adaxially white, abaxially green, 1.5–3.5 cm long, keeled, terminating in an awn to 2–5 mm long. Petals white, 1.5–4 cm long. Corona of 4 series of filaments, blue in upper ⅓, white in middle and blackish purple at base; outer two (0.8–) 1.5–2.5 cm long; inner series 1–2 mm long. Operculum white and membranous at base, filamentous, dark purple for most of length, 3–5 mm long. Androgynophore straight, 8–10 mm long. Stamens 5. Styles 3. Fruit an ovoid-globose berry, 3–6 cm long, 3–4 cm wide, yellow-orange to orange at maturity. Seeds coarsely reticulate.

It is a subtropical climate plant. It grows naturally on the edges of secondary vegetation in eastern Brazil. They can grow in temperatures down to-9°C. Plants can re-grow from underground roots. It prefers plenty of water, moist soil and warm conditions. It grows to 34°S in Argentina. In Argentina it grows from sea level to 2,000 m above sea level. In XTBG Yunnan. It suits hardiness zones 7-10. In Sichuan.

This species is widely grown as an ornamental for its colourful flowers and interesting foliage, and due to its tolerance of low temperatures it can be grown in cool temperate areas. Originally introduced into Australia for the ornamental appeal of its flowers. It has edible fruit that are commercially harvested in some regions of the world, but in Australia this species is mainly used as a vigorous rootstock that has good resistance to fusarium wilt for grafted P. edulis, which has a superior taste and provides the majority of Passionfruit in Australia (Page 1984; Cole et al. 1992).

Plants are mostly grown from seed. They can be grown from cuttings. Bottom heating the seeds at 20-26°C can result in germination at 1-2 weeks, at lower temperatures seeds can take up to 10 weeks to germinate. Plants should be topped back for better fruit production.