How to Grow Jiaogulan in Australia

Jiaogulan (Gynostemma pentaphyllum) is a climbing perennial vine of the cucumber family (Cucurbitaceae), grown for its fine, five-fingered leaves. It is native from Japan through Asia to New Guinea, not Australia, yet it grew well outdoors in a University of Sydney trial at Randwick. The seed is the hard part: jiaogulan seed is slow and erratic, and untreated seed often never comes up.

Three mistakes that matter

1. Sowing untreated seed and giving up early. The seed is dormant, and untreated seed can take two months or never sprout. Chip the coat, keep the tray warm and wait eight weeks, as Germinating the seed explains.
2. Planting it in hot, dry, full sun. The leaves curl and scorch in dry heat, and growth stalls. Give it morning sun and afternoon shade, soil that stays evenly moist, and a thick mulch. In the Sydney trial, a vine in full sun did well once its leaves covered the soil and it was watered often.
3. Digging out a vine that has died back. The top growth dies in winter, but the plant survives as underground stems that shoot again in spring. Mark the spot, mulch it and wait for warm nights before deciding it is dead.

When to plant

Warmth decides the sowing date: the seed wants 20 to 25°C in the tray, and young vines are cut down by frost. Sow in spring and early summer in most of Australia, earlier on a seedling heat mat, and plant out once frost has passed. An established vine usually returns each spring, so one sowing can last for years.

Late sowings still germinate if trays stay warm, but a vine sown after midsummer has less time to build underground stems before winter. In frosty districts, keep late seedlings in pots under cover until spring. The harvest months suit an established vine; a vine in its first year from seed is often ready later.

Site, soil and setup

Jiaogulan grows wild in forest thickets, on stream banks and along shaded mountain roadsides, and a garden copy of that setting suits it best.

Dig in a 5 cm layer of compost, or 5 to 10 cm of well-rotted cow or horse manure 4 to 6 weeks before planting. Where a pH test reads below 6.5, dig in garden lime at 100 to 200 g per square metre 4 weeks ahead. Jiaogulan is a perennial, so give it a permanent spot outside the vegetable rotation.

Container growing

A pot suits jiaogulan well and lets you move it out of hot sun or under cover in winter. Its roots run just below the surface, so choose a wide pot over a deep one. A pot 40 cm across, holding about 28 L, suits one vine. Fill it with a quality potting mix and blend in a few handfuls of compost.

• Water: keep the mix evenly moist, as watering pots in an Australian summer explains.
• Feed: worm casting liquid diluted to weak tea colour, fortnightly from spring to late summer.
• Position: morning sun and afternoon shade, sheltered from wind.
• Support: a wire obelisk or a small trellis pushed into the pot.

Germinating the seed

Jiaogulan seed is dormant when it ripens: it carries natural chemicals that hold back germination, inside a tough brown coat. That is why fresh, untreated seed often sits in the mix for weeks. In trials described in a Chinese patent, untreated seed gave under 20 per cent. Chipping the coat changes the picture: at the Royal Botanic Gardens, Kew, nine of ten chipped seeds germinated within 28 days at 25°C.

The store listing puts germination at 30 to 50 per cent at best, over 2 to 8 weeks at 20 to 25°C. Sow every seed in the packet, two or three to a pot, and expect a few plants rather than nine.

A Chinese patent pairs a plant hormone soak with a short chill, but that is not a home method. More on the kitchen methods is in Soaking, Scarification and Cold Stratification.

When nothing comes up

• Too cool. Germination slows in a cool tray; keep it at the warmth given in When to plant, on a heat mat if need be.
• Coat left whole. Water may not be getting in; chip any seed you still have and sow it again.
• Mix too wet or too dry. Soggy mix rots seed and dry mix stalls it; keep it damp under a lid, with humidity around 70 to 80 per cent.
• Sown too deep. Cover the seed with about 5 mm of mix, roughly its own width, and no more.
• Old or warm-stored seed. The seed is short-lived, often good for only about a year. Sow it soon after it arrives, and keep any spare sealed and dry in the fridge.
• Given up too soon. Keep the tray warm and damp for at least eight weeks before tipping it out.

Sowing Seeds

Start jiaogulan in pots under cover from seed chipped as Germinating the seed describes, because nine seeds are too few to risk in open ground.

Starting under cover

• Fill small pots with fresh seed raising mix and water them before sowing.
• Sow two or three seeds per pot, 5 mm deep, and firm the mix over them.
• Cover the pots with a clear lid or bag and keep them at the warmth given in When to plant, out of direct sun.
• Lift the lid for a few minutes each day so air moves over the mix.
• Once shoots appear, take the lid off and give bright light, so seedlings do not stretch.
• Keep the strongest seedling in each pot and snip the others at soil level.

Transplanting

Plant out once seedlings have several true leaves and the last frost has passed. Harden them off first (get them used to outdoor sun and wind over about a week), as hardening off seedlings describes. Set plants 30 cm apart at the foot of the support. Water them in with half-strength seaweed solution and lead the first shoot onto the trellis.

Care by growth stage

Water decides this crop more than feeding does, so keep the soil steadily moist. Compost or manure in the soil is usually all the feeding it needs, so keep liquid feeds light.

If growth stalls in poor soil, scratch in a light application of all-purpose controlled release granular (NPK around 14-5-10) in spring.

Vine Training

Jiaogulan climbs by coiled tendrils but just as happily sprawls along the ground, where its stems root and spread. Training keeps it up on the support, tidy and easy to pick.

• Lead new shoots onto the trellis and tie in any that wander, until the tendrils take hold.
• Cut back harvested stems to the lower leaves, so fresh shoots grow from the base.
• Clear frosted or dead top growth in late winter, before new shoots appear.
• Lift stems that have rooted where they touch the soil, and pot them up as new plants, as layering describes.
• Take stem cuttings with two nodes (leaf joints) and root them in water or damp mix, though some are slow; see rooting cuttings in water.
• Dig up and replant 15 cm pieces of rhizome (creeping underground stem) just below the surface to start new plants.

Companion planting

Choose neighbours for the shade they cast and the diseases they share.

Grows well with

• Tall sunflowers or corn on the western side, which cast afternoon shade over the vine.
• Lettuce in the shade at the foot of the trellis in summer, which grows well out of the hottest sun.

Keep apart

• Cucumber, pumpkin and zucchini, which host the powdery mildew species recorded on jiaogulan overseas.
• Mint, whose runners compete with jiaogulan's spreading underground stems for the same moist soil.
• Passionfruit and other strong climbers, which smother it on a shared trellis.

Harvesting Leaves

Start cutting once vines reach 2 to 3 m and the leaves are full-sized and green. In the tropics and subtropics vines are often cut four or five times a year. The Sydney trial, grown partly in a glasshouse, cut in March and September.

• Cut in the morning, once dew has dried from the leaves.
• Take whole leafy stems with secateurs, leaving the base and lower leaves to regrow.
• Discard yellow, mildewed or mite-damaged leaves at picking time.
• Keep cut stems in the shade until you finish picking.

Spread the stems in a thin layer on a rack in the sun or an airy spot out of the rain. An oven at about 50°C also works; the Sydney trial dried its harvest over about three days. Store the dried leaves in sealed, labelled jars or bags in a cool, dry cupboard, away from damp, which brings mildew and rot.

Traditional use and history

The plant's written story in China begins as a famine food, not a medicine.

The first written record comes from the early fifteenth century. Zhu Su compiled the Jiuhuang Bencao, a book of famine foods, under the Ming dynasty. It described jiaogulan as a wild plant to eat in hard times, with a drawing to help people find it.

Li Shizhen's Bencao Gangmu, the great Chinese herbal of the late sixteenth century, recorded it among medicinal plants. Traditional Chinese medicine describes the herb as slightly bitter in taste and neutral in nature. A study of wild food plants in the Qinling Mountains of Shaanxi also recorded its leafy stems.

Grow the vine from seed or cuttings rather than buying wild-gathered material.

Safety

Jiaogulan is sold as seed for growing, and nothing here is advice to eat or take any part of the plant. Anyone thinking of using a plant should first seek advice from a qualified health practitioner.

Common problems

Leaves curl and scorch in summer. Dry heat is the cause, as Three mistakes that matter explains. Put up shade cloth or move a pot into shade; a wilted vine usually recovers after a good soak.

Leaves turn yellow. Too much water is a likely cause: the Sydney trial saw yellowing until it cut back its watering. Let the surface dry slightly between waterings and improve drainage.

No berries on the vine. Each plant is male or female (dioecious), and only a female near a male sets the small black berries. Male plants far outnumber females in the wild, and both sexes give leaves.

Pale, sparse growth. Deep shade weakens the vine over a season, so move it to dappled light or morning sun. Spindly seedlings need brighter light at once; see leggy seedlings.

Vine spreading across the bed. Stems root wherever they touch moist soil and form new plants, so keep the vine up on its support and lift strays each spring.

Pests and diseases

Few pests trouble jiaogulan, and most problems come from dry heat, damp seed trays or crowded, humid foliage.

Two-spotted mite (Tetranychus urticae). It leaves foliage pale and stippled with fine webbing underneath, and the Sydney trial recorded it on jiaogulan. Hose leaf undersides with a strong jet early on three mornings in a row, and avoid broad-spectrum sprays that kill predatory mites. Read more

Garden snail (Cornu aspersum). Snails, and slugs with them, chew seedlings and soft spring shoots at night; established vines in the Sydney trial resisted them. Hand-pick after dark, or trap them in shallow dishes of beer. Read more

Powdery mildew (Podosphaera xanthii). A white powdery coating spreads over leaves, and this fungus, recorded on jiaogulan in Korea, also attacks cucumber, pumpkin and zucchini in Australia. Water the soil rather than the leaves, remove the worst leaves, and spray 1 part full-cream milk to 10 parts water. Read more

Damping off (Pythium species and Rhizoctonia solani). Seedlings rot before they emerge or collapse at soil level, a real risk in warm, covered trays kept for weeks. Use fresh seed raising mix and clean pots, air the tray daily, and water only enough to keep it damp. Read more

Prevention first

• Raise seed pots off the ground, out of rain and hose splash, and scrub pots and tools between uses.
• Train the vine up its support so air moves through the leaves.
• Water in the morning, so leaves dry before night.
• By day, check under pots and in thick mulch, where snails hide from the sun.

Tips

1. Once you have a good vine, multiply it from cuttings or rhizome pieces rather than sowing more seed.
2. In frosty districts, keep a rooted piece in a pot under cover over winter as insurance.
3. If a female plant sets berries, pick them once they turn black, clean out the seed, dry it and store it in the fridge.
4. Expect flowers from about September to May and berries from about October to June. A vine with no berries by winter may be male, or still too young.