Luffa aegyptiaca aka Dishrag Gourd

Luffa aegyptiaca, or sponge gourd, belongs to the cucumber family. This annual vine grows fast and climbs with tendrils. Kew places its native range in the Indian Subcontinent. Long cultivation has made its exact wild origin hard to trace. People now grow it across the tropics for food and fibre. It has escaped gardens in many warm parts of the world.

Size varies with climate and growing conditions. RHS gives heights of 8–13 feet [2.5–4 metres]. North American sources report vines reaching 30–50 feet [9–15.2 metres]. Allow a spread of about 1–3 feet [0.3–1 metre]. The stems need a strong fence or trellis for support. Broad green leaves have deep lobes, much like maple leaves. They reach about 0.8 feet [0.25 metres] across. Short white hairs cover both sides and give them rough surfaces.

Yellow flowers appear from summer into autumn and attract bees. Male flowers grow in small groups; female flowers grow alone. Sources give flower widths of 0.16–0.33 feet [0.05–0.10 metres]. Insects pollinate them, though hand pollination can improve fruit yield. The smooth green fruits have a long, round shape. Reported lengths range from about 0.6–2 feet [0.18–0.61 metres]. Each fruit holds many flat, round, black seeds. As fruits ripen, their flesh forms a tough fibre network.

Grow this vine in full sun and moist, well-drained soil. Rich loam suits it, though it can grow in poor soil. It needs warmth and at least four months without frost. Start seeds indoors where the warm season is short. RHS rates it H1C, for outdoor growth in warm summers. Missouri Botanical Garden lists USDA zones 5–11 for annual cultivation. That range does not mean it survives winter frost. Powdery mildew, downy mildew and leaf spots can affect it. Beetles, squash bugs, thrips, aphids and spider mites may cause trouble.

Young fruits serve as vegetables, either raw or cooked. Useful Tropical Plants also records cooked shoots, leaves and flower buds. It lists roasted seeds and oil pressed from seeds. RHS warns that other parts can harm people and pets. Do not eat bitter fruit. Older fruits become too fibrous to eat. Their dried fibres make bath sponges, scrubbers, mats and filters. Traditional medicine uses are recorded, but these are not proven treatments.