Kangkong Weed in Rice Fields: How to Spot and Control It
The kangkong weed is the same water spinach we cook at home. But inside a rice field, it grows as a damo. It creeps over the mud or floats on water in irrigated and rainfed lowland rice fields in the Philippines. This page shows you how to spot it and why it matters for your palay. Then it shows how to control it before it spreads.
What Is Kangkong Weed?
Kangkong is a creeping water plant in the morning glory family, Convolvulaceae. In English it is called water spinach. Most Filipinos know it as an everyday vegetable for sinigang and adobo. Inside a palay field, though, nobody planted it there, so it counts as a kangkong weed. Its stems spread over the mud or float on the water.
This plant shows up in irrigated and rainfed lowland rice fields. Being a perennial, it keeps growing from season to season. It spreads in two ways. First, its hollow stems root at the joints, and a cut piece can grow into a new plant. It also makes seeds. That is why kangkong growing in a canal or ditch can creep into the paddy.
| Name | Kangkong weed |
|---|---|
| Scientific name | Ipomoea aquatica |
| Family | Convolvulaceae |
| Weed group | Broadleaves (see the three groups) |
| Local names | Kangkong |
| Life cycle | Perennial |
| Spreads by | Seeds and cuttings |
| Where it grows | Irrigated and rainfed lowland rice fields |
How to Identify Kangkong Weed
Look for smooth, slender, hollow stems creeping over the mud or floating on the water. Roots grow from the joints along the stem. The leaves sit one at a time along the stem, not in pairs, and their shape varies from plant to plant. Like other broadleaf weeds, the leaves are wide with netted veins, unlike grasses and sedges. When it blooms, the flowers are funnel shaped and range from white to purple.
- Smooth, hollow stems creeping across the mud or floating on the water.
- Roots growing from the joints of the stem wherever it touches mud or water.
- Leaves set one by one along the stem, with shapes that vary between plants.
- Funnel shaped flowers, white to purple, opening above the creeping stems.
- Thick patches of the same leafy plant growing in canals, ditches and low wet spots.
Why It Hurts Your Palay
How much harvest kangkong takes from rice has not yet been reported. Still, it is not harmless. The bigger worry is golden kuhol. When no rice is in the field, kangkong serves as an alternate host for golden apple snails. That means the snails can feed and survive on it between crops.
So when you transplant or sow again, the snails are already waiting. Golden kuhol does its worst damage on young rice and fresh punla. Like other creeping weeds, kangkong can also take some light, water and fertilizer where it grows thick between the hills.
How to Control Kangkong Weed
- Pull every creeping stem out of the paddy, roots and all. Each joint can root, so any piece left in the mud may grow again.
- Clear kangkong from canals and ditches around the field after harvest. This removes the food that keeps golden kuhol alive between crops.
- If you want kangkong to eat, grow it in a separate plot or pond, not inside or beside the rice paddy.
- Pick up golden kuhol and their pink egg clusters while you clear the kangkong. Both jobs protect your next crop.
What to Do at Each Age of Your Rice
- 0 to 5 days: keep the soil saturated. Use a pre emergence herbicide only if the field had many weeds last season.
- 6 to 10 days: hand weed in transplanted rice. In direct seeded rice, this is the window for an early post emergence spray.
- 11 to 20 days: keep water in the field, weed by hand or with a rotary weeder, and let Azolla and the Altica beetle help. Spray only if those fail.
- 21 to 30 days: top up the water and keep weeding. Spray only if weeding fails.
- 31 to 40 days (transplanted rice): hand weed. A spray this late is only a rescue.
- After any post emergence spray, bring the water back within 1 to 3 days at 3 to 5 cm and hold it for 4 to 5 days. Keep young rice above it.
Active Ingredients That Work on Broadleaves
If water and weeding cannot hold kangkong weed down, choose an active ingredient that works on broadleaves at the age of your rice. Each active ingredient in it is in a herbicide registered in the Philippines for rice. Shop by the ingredient on the label, never by the brand. If your field also has other kinds of weeds, the weed control helper in anee.io finds the ingredients that cover all of them.
| Rice age (days after planting) | Transplanted rice (lipat tanim) | Direct seeded rice (sabog tanim) |
|---|---|---|
| 0 to 5 days | Pretilachlor, Oxadiazon, Butachlor plus 2,4 D IBE, Pyrazosulfuron ethyl plus pretilachlor, Imazosulfuron, Penoxsulam plus butachlor, Tefuryltrione plus triafamone, Thiobencarb plus 2,4 D IBE | Pretilachlor, Oxadiazon, Pretilachlor plus butachlor, Butachlor plus 2,4 D IBE, Pendimethalin, Pyrazosulfuron ethyl plus pretilachlor, Butachlor with safener |
| 6 to 10 days | Butachlor plus propanil, Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Penoxsulam plus cyhalofop butyl, Pendimethalin, Cyhalofop butyl plus propanil, Imazosulfuron, Propyrisulfuron, Clomazone plus propanil, Thiobencarb plus propanil, Flucetosulfuron, Cyhalofop butyl plus florpyrauxifen benzyl | Butachlor plus propanil, Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Pyribenzoxim plus cyhalofop butyl, Penoxsulam plus cyhalofop butyl, Cyhalofop butyl plus propanil, Pyrazosulfuron ethyl plus pretilachlor, Pendimethalin, Propyrisulfuron, Clomazone plus propanil, Thiobencarb plus propanil, Pretilachlor plus pyribenzoxim, Penoxsulam, Flucetosulfuron, Cyhalofop butyl plus florpyrauxifen benzyl |
| 11 to 20 days | Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Pyribenzoxim plus cyhalofop butyl, Penoxsulam plus cyhalofop butyl, Metamifop plus bispyribac sodium, Bentazone, Cyhalofop butyl plus ethoxysulfuron, Propyrisulfuron, Fenoxaprop P ethyl plus ethoxysulfuron, Flucetosulfuron, Carfentrazone ethyl, Florpyrauxifen benzyl, Cyhalofop butyl plus florpyrauxifen benzyl | Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Pyribenzoxim plus cyhalofop butyl, Penoxsulam plus cyhalofop butyl, Metamifop plus bispyribac sodium, Bentazone, Pyribenzoxim, Cyhalofop butyl plus ethoxysulfuron, Propyrisulfuron, Fenoxaprop P ethyl plus ethoxysulfuron, Flucetosulfuron, Carfentrazone ethyl, Florpyrauxifen benzyl, Cyhalofop butyl plus florpyrauxifen benzyl |
| 21 to 30 days | 2,4 D amine, 2,4 D IBE, MCPA, Metamifop plus bispyribac sodium, Bentazone, Metsulfuron methyl plus chlorimuron ethyl, Fenoxaprop P ethyl plus ethoxysulfuron, Carfentrazone ethyl | 2,4 D amine, 2,4 D IBE, Cyhalofop butyl plus bispyribac sodium, Pyribenzoxim plus cyhalofop butyl, MCPA, Metamifop plus bispyribac sodium, Bentazone, Metsulfuron methyl plus chlorimuron ethyl, Pyribenzoxim, Carfentrazone ethyl |
| 31 to 40 days | Metsulfuron methyl plus chlorimuron ethyl | Not listed for direct seeded rice |
Spray Safely
Use only herbicides registered with the Fertilizer and Pesticide Authority, and follow the label on the pack: the rate, the timing, the water and the protective clothing. Switch herbicide groups between seasons so the weeds do not learn to survive them. Our guide to herbicides for rice explains the groups.
Keep Kangkong Weed Out Next Season
- Plant clean, certified seed. Weed seeds mixed into the punla are the easiest way in.
- Keep the seedbed, the canals and the bunds free of weeds, so seed does not wash or blow into the paddy.
- Plow and harrow well, and rake out the runners, roots or pieces you turn up. A small piece left in wet soil can grow a new plant.
- Pull escapes before they flower and set seed, and carry them out of the paddy instead of leaving them on the bund.
- Keep the field clean after harvest and through the fallow, so fewer seeds build up in the soil for next season.
These steps work for every broadleaf weed in the paddy, not only this one. The weed management guide puts them in order for a whole season.
Not Sure It Is Kangkong Weed?
Take a clear photo of the leaf, the stem and the flower or seed head, then ask Anee, the smart farm technician in anee.io, in Tagalog or English. Anee tells you which weed it most likely is, its group, and what to do at the age of your rice. You can also put the weeding days on your cropping calendar, so the team knows when to go in.
anee.io keeps your weeding, spraying and water on one calendar, and Anee answers when a plant looks wrong.
- Weeding days on the season calendar
- Photos and notes for every lot
- Anee, the smart farm technician, in Tagalog or English
Questions Farmers Ask About Kangkong Weed
What is kangkong called in English?
How do I control kangkong weed in my rice field?
Is the kangkong weed in my field the same as the kangkong in the market?
Get Kangkong out of your field
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