Valley Redstem: How to Identify and Manage It in Rice Fields
Valley redstem is a broadleaf weed of irrigated and rainfed lowland rice fields in the Philippines. It grows upright to about half a meter, with smooth stems, paired leaves and small purplish flowers. In thick stands it can cut your harvest. This page shows how to spot it early and how to control it before it seeds.
What Is Valley Redstem?
This weed carries the scientific name Ammannia coccinea, and it belongs to the loosestrife family. It has no common Filipino local name, so this page uses its English name. Valley redstem grows in both irrigated and rainfed lowland rice fields. It does well in wet paddies, which is why it can stand right among the rice hills.
As an annual, each plant lives for one season. It spreads by seed, and its small flowers turn into seed capsules close to the leaf joints. The English name comes from its stems, which can take on a red tint as the plant ages. Because it lives and seeds within one crop, stopping it before it flowers keeps next season's field cleaner.
| Name | Valley redstem |
|---|---|
| Scientific name | Ammannia coccinea |
| Family | Lythraceae |
| Weed group | Broadleaves (see the three groups) |
| Local names | None recorded |
| Life cycle | Annual |
| Spreads by | Seeds |
| Where it grows | Irrigated and rainfed lowland rice fields |
How to Identify Valley Redstem
Look for an upright, branched plant up to about 50 centimeters tall with smooth stems. Its leaves grow in pairs, one across from the other on the stem. At the base, each leaf widens into two small lobes, like little ears, that hug the stem. As a broadleaf weed, it has flat leaves with netted veins. Small purplish flowers sit close to the stem where the leaves join it, so check the leaf joints when you walk the paddy.
- Upright, branched plants up to about 50 centimeters tall with smooth, hairless stems.
- Leaves in pairs, with each pair facing each other across the stem.
- Leaf bases with two small ear shaped lobes that wrap around the stem.
- Small flowers with purplish petals sitting tight where the leaves join the stem.
- Stems that may take on a reddish tint as the plant grows older.
Why It Hurts Your Palay
Valley redstem can take a real bite out of your harvest. When more than 100 plants grow in one square meter, rice yield can drop by up to 21 percent. So a thick, unweeded patch poses a real threat to your income. The weed takes light, water and fertilizer that your palay needs, and its upright stems crowd the rice hills.
Besides yield loss, its seeds can end up in harvested grain and travel to other fields. Thick stands also shelter insects and other pests close to the crop. So treat a carpet of young seedlings as an early warning, not a small problem.
How to Control Valley Redstem
- Hand weed early, while seedlings are small and easy to pull, so the stand never gets close to 100 plants per square meter.
- Pull plants before the purplish flowers set seed, and carry them out of the paddy so seeds stay off the soil.
- Level the field well so water covers it evenly and the rice can grow ahead of the weed seedlings.
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 valley redstem 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 Valley Redstem 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.
- Prepare the land well: flood, plow, let the weed seeds sprout, then kill them when you harrow. Level the field so water covers it evenly.
- 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 Valley Redstem?
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 Valley Redstem
What is valley redstem commonly called?
How do I control this weed in my rice field?
How many plants does it take to hurt my yield?
Get Valley Redstem out of your field
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