Water Hyacinth: How to Spot and Control It in Rice Fields
Water hyacinth is a floating weed with swollen, spongy leaf stalks and purple flowers. Many Filipino farmers simply call it water lily. It grows in irrigated lowland rice fields and also in the canals that feed them. This page shows you how to spot it and how it hurts your palay and your irrigation. It also shows how to control it before it covers the water.
What Is Water Hyacinth?
Water hyacinth floats on the water instead of rooting in the soil. Its roots hang down into the water like a beard. A short stem holds a rosette of shiny, rounded leaves on swollen, spongy stalks that work like floats. Many Filipinos call it water lily, but it is not a true lily. It belongs to the pickerelweed family, Pontederiaceae, and weed experts group it with the broadleaves.
You will find it in irrigated lowland rice fields and their canals. It is a perennial, so it keeps living from season to season. It spreads in three ways. First, it sends out runners that grow new daughter plants. Next, any broken piece can float away and start a new plant. Finally, it also makes seeds. That is why one small clump can cover a canal before you notice.
| Name | Water hyacinth |
|---|---|
| Scientific name | Eichhornia crassipes |
| Family | Pontederiaceae |
| Weed group | Broadleaves (see the three groups) |
| Local names | Water lily |
| Life cycle | Perennial |
| Spreads by | Stolons, plant fragments, seeds |
| Where it grows | Irrigated lowland rice fields |
How to Identify Water Hyacinth
Look for plants floating on the water surface in a tight rosette. The leaves are oval to almost round, shiny and thick. If you squeeze a leaf stalk, it feels swollen and spongy, like foam, because it is full of air. Below the water, dark roots often hang loose instead of gripping the soil. Its leaves are broad, unlike the narrow blades of grasses and sedges. When it flowers, it shows many purple blooms on an upright stalk.
- Rosettes of shiny, rounded leaves floating on the water in the paddy or canal.
- Swollen, spongy leaf stalks that feel like foam when you squeeze them.
- Dark roots trailing below the plant, often hanging loose in the water.
- Many purple flowers clustered on an upright stalk above the leaves.
- Small daughter plants joined to the mother plant by runners on the water.
- Floating mats that slow canal flow or crowd the water at the paddy inlet.
Why It Hurts Your Palay
This weed hurts a rice farm in two places, the canal and the paddy. In the canal, thick mats slow the flow and block the water your palay needs. Gates and inlets clog, so fields at the end of the line may get too little water. Inside the paddy, the floating plants crowd the rice and hold back its growth. Together, these effects can cause heavy economic losses in rice fields.
There is another risk. Water hyacinth can carry disease organisms that infect several other crops. So a canal full of it is not only a water problem. It can also pass trouble on to the crops you or your neighbors grow nearby.
How to Control Water Hyacinth
- Scoop the plants out of canals and the paddy with a net or rake while the patch is still small. Daughter plants multiply fast on open water.
- Pile removed plants on high, dry ground far from the water. Broken pieces that fall back into a canal can start new plants.
- Put a simple screen or net at the paddy water inlet. It catches floating plants before they drift in from the canal.
- Work with your irrigators association to clear the canals together. Plants left upstream will float down and fill your field again.
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 water hyacinth 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 Water Hyacinth 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 Water Hyacinth?
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 Water Hyacinth
What do Filipino farmers call water hyacinth?
How do I get rid of water lily in my rice field and canal?
Why does it come back after I clear the canal?
Get Water Hyacinth out of your field
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