Gadenin日本語Get the appThe plant is the hazard
Anredera cordifolia is classed among the worst environmental weeds of any warm-temperate or subtropical region. In Australia it is a Weed of National Significance; it is a declared or regulated pest in New Zealand, South Africa, several US states and much of the Pacific, and it is illegal to grow, sell or move in a number of places. If it gets out of your garden it does real damage: it forms a dense mat over shrubs and trees, cuts out their light, and then brings the canopy down under sheer weight. Riverbanks and bush edges are where it does the most harm, and it gets there through garden waste and water.
It spreads two ways and both are hard to stop. Above ground it drops warty aerial tubers from the leaf joints by the hundred; every one is a complete plant, they survive for years, and they travel in soil, in green waste, on boots, in water and in floodwater. Below ground it makes fleshy tubers, and any piece left in the soil regrows. Cutting the vine down does nothing on its own. In many places it does not even need to set seed to be unstoppable.
So the honest position is this: if you are not able to keep it in a pot on a hard surface with a weekly tuber sweep, do not grow it. And if it is already in open ground in your garden, the correct response is removal, not management.
Check your national, state and local weed lists before growing, and again before disposing of any material. Where the plant is prohibited, growing it is an offense regardless of how carefully you contain it, and some authorities will help with removal.
Spotting an escape early
Look for a single heart-shaped, glossy, slightly fleshy leaf on a thin twining stem, coming up somewhere you did not plant anything: a paving joint, the gravel by a downpipe, the edge of a shrub bed, a neighboring pot. At that size it pulls out easily, and that is the only stage at which removal is trivial. Within one warm season the same seedling is a ten-foot (3 m) vine with a tuber under it.
Check the places tubers collect: the low point of the paving, the catch tray, under the pot, the gutter line, and anywhere runoff sheets across after heavy rain. Also check any pot that has stood next to the plant, and any bag of potting mix or compost that has been open nearby. Once a month, look over the fence line too, because a tuber that rolls under a fence becomes somebody else's problem and eventually comes back as yours.
The plant is easy to confuse with a couple of harmless climbers when small, so it is worth learning its two giveaways: the stems are thin, slightly succulent and twine anticlockwise, and mature ones carry knobbly gray-green warts at the leaf joints. Nothing else in a vegetable garden looks like those warts.
| Problem | How it shows | What to do |
|---|---|---|
| Escaped seedling in a crack or bed | Single heart-shaped leaf on a thin twining stem | Pull immediately with its tuber, bag it, recheck the spot monthly |
| Established plant in open ground | Mass of vine over a shrub or fence, warty stems | Cut, dig every tuber, bag all material, monitor for years |
| Tubers in the catch tray | Warty pea to walnut sized beads | Collect and destroy weekly; never compost |
| Aphids on shoot tips | Clustered green or black insects, curled new leaves | Wash off with water or soap spray; unpicked tips recover fast |
| Spider mites in hot dry spells | Fine stippling, dull leaves, webbing under the leaf | Raise humidity, wash the foliage, cut back the worst growth |
| Caterpillars and leaf beetles | Ragged holes chewed through leaves | Hand pick; damage is cosmetic on a fast-growing vine |
| Rot at the base | Blackened, soft stem at soil level, sudden collapse | Reduce watering, improve drainage, never leave the pot in standing water |
Removing it properly
Removal is a two-part job and skipping either part guarantees regrowth. First you take out the top growth without scattering tubers, then you dig out every underground tuber you can find. Then you come back, repeatedly, for at least two years, because tubers that were too small or too deep to find will shoot when the ground warms.
Work slowly and deliberately. Ripping a mature vine off a fence or a shrub in one movement flings tubers over a wide radius, and that single moment can turn a contained problem into an infestation across the whole garden. Everything you remove goes into sealed bags for landfill, deep burial where that is permitted, or long-term drowning. Never into compost, never into council green waste unless your authority specifically says it accepts this species, and never onto a bonfire pile that sits for weeks before you light it.
- Sheet the ground first Lay tarpaulins under and well beyond the whole plant before you cut anything. This is the step people skip and it is the one that decides whether removal works.
- Cut the vine down in short lengths Snip the stems into arm-length pieces and lower them onto the sheet rather than pulling long runners down. Long runners whip and scatter tubers everywhere they touch.
- Bag the top growth immediately Fold the sheet and tip everything straight into heavy sealed bags. Do not stack cut vine on the ground to deal with later; it stays alive and keeps shedding.
- Dig out every tuber Fork over the soil around the base to at least a foot (30 cm) deep and wider than the old canopy, sifting for fleshy tubers and fragments. Take out anything that looks like a potato and anything that looks like part of one.
- Sweep and rinse everything Sweep the paving out well beyond the working area, check the gutter and drain covers, and rinse tools, boots, gloves and the wheelbarrow before they leave the site.
- Return every month for two years Mark the location and check it monthly through each warm season. Pull new shoots the moment they appear; each one you miss rebuilds a tuber and starts the clock again.
Keep a map, not just notes
Record every location where you have found a stray shoot, with the date, and keep that list going for years. Underground tubers can sit dormant through a whole cold season and shoot the following summer, so a location that has been clear for eight months is not clear. A simple sketch of the garden with dated marks on it is more useful here than any amount of written description.
Log removal work too: the date you cut the top growth, the date you dug, how many tubers came out and where the deepest one was. If regrowth appears, that record tells you whether you are looking at a missed tuber in a known spot or a fresh arrival from somewhere else, and those two need different responses.