Dayflower / kena (Commelina)
A succulent creeping weed with bright blue flowers that roots at its nodes and even sets seed underground — hard to kill by hoeing.
- Type
- Broadleaf weed (creeping, succulent)
- Life cycle
- Annual/perennial; roots at nodes; underground seed
- Spreads by
- Seed (incl. underground) & node-rooting stems
- Main harm
- Dense cover competes; hard to kill by hoeing
Overview
Dayflower or kena (Commelina benghalensis) is a succulent, creeping broadleaf weed common in rice, maize, sugarcane, vegetables and orchards, especially in moist, warm conditions. It has fleshy, jointed, creeping stems that root at the nodes, oval leaves with a sheath around the stem, and small, bright blue flowers (usually three-petalled) that open for part of the day. It spreads low and can form a dense cover in the crop.
It is a difficult weed for two reasons. First, its fleshy stems root at the nodes, so pieces left after hoeing re-root and regrow. Second — and unusually — it produces two kinds of seed, including underground (subterranean) seeds near the base, so it can keep reproducing even when the top is removed, and it tends to tolerate or escape some common herbicides. So it needs clean removal (take the pieces off the field), a competitive crop, and an integrated approach rather than reliance on a single spray.
How to identify it
- Fleshy, jointed, creeping stems that root at the nodes.
- Oval leaves with a sheath wrapping the stem at the base.
- Small, bright blue flowers (usually three-petalled) that open for part of the day.
- Spreads low in moist, warm crops — rice, maize, sugarcane, vegetables, orchards.
Why it is a problem
- Forms a dense low cover that competes with the crop for moisture, nutrients, light and space.
- Its fleshy stems root at the nodes, so pieces left after hoeing re-root and regrow.
- It sets underground (subterranean) seed as well as normal seed, so it keeps reproducing even when the top is removed.
- It tends to tolerate or escape some common herbicides, making it hard to control with one spray.
Cultural & preventive control
- Remove it cleanly — take the weeded pieces off the field rather than leaving node-bearing stems to re-root.
- Control it early and grow a competitive, well-established crop that shades it out.
- Use mulch and manage moisture, and keep field edges clean.
- Prevent seed set (including the underground seed) as far as possible by removing it early and repeatedly.
Herbicide control
- Use recommended herbicides for the crop, but note Commelina tolerates/escapes some — choose an effective one and treat when the weed is small.
- Combine herbicides with clean hoeing/removal and a competitive crop, since one spray often does not finish it.
- Rotate herbicide groups and follow up on re-growth.
- Confirm the current effective herbicide for Commelina in your crop with your local KVK.
Integrated management
- Combine early clean removal (off the field), a competitive crop, mulch and effective herbicides with follow-up.
- Never leave node-bearing stems on moist soil — they re-root.
- Keep at it over the season, since underground seed and node-rooting let it persist.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
What is the creeping weed with bright blue flowers rooting along its stems in my rice/maize?
A succulent creeping weed with fleshy jointed stems that root at the nodes, oval sheathing leaves, and small bright blue (usually three-petalled) flowers is dayflower or kena (Commelina benghalensis). It forms a dense low cover and is hard to kill because its stems re-root and it even sets underground seed. Control it by removing it cleanly (take the pieces off the field), growing a competitive crop with mulch, and using an effective herbicide with follow-up — one spray alone often does not finish it.
Why is dayflower (kena) so hard to control?
Two reasons. Its fleshy stems root at every node, so pieces left after hoeing re-root and regrow, and — unusually — it produces underground (subterranean) seed near the base as well as normal seed, so it can keep reproducing even when you remove the top growth. On top of that it tolerates or escapes some common herbicides. So no single measure finishes it: you need clean removal off the field, a competitive crop, mulch, and an effective herbicide with follow-up, kept up over the season.
Does hoeing control Commelina?
Hoeing helps only if you remove the weeded pieces from the field, because Commelina’s fleshy stems root at the nodes, so stem fragments left lying on moist soil simply re-root and regrow. And because it also sets underground seed, even good hoeing does not stop all reproduction. So combine clean removal (take the pieces off, or let them dry fully) with a competitive crop, mulch and an effective herbicide, and follow up on re-growth through the season for lasting control.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.