Horse purslane (Trianthema)
A low, fleshy, fast-spreading summer weed that carpets the ground after the first rains and competes hard with young crops.
- Type
- Broadleaf weed (annual, summer, fleshy)
- Life cycle
- Annual; prolific seed; stems re-root
- Spreads by
- Seed; succulent stems re-rooting
- Main harm
- Fast carpet smothers young crops
Overview
Horse purslane (Trianthema portulacastrum) is a fast-growing, low, fleshy summer broadleaf weed of cotton, groundnut, soybean, vegetables and other kharif crops. It has succulent, reddish, spreading (prostrate) stems and small, fleshy, roundish leaves in unequal pairs, and small pinkish flowers. After the first monsoon rains it germinates and spreads very fast, carpeting the ground between the young crop rows within days.
That rapid early carpet is exactly the problem: it competes strongly with the young crop for moisture, nitrogen, light and space at the crucial establishment stage, and can smother a slow-starting crop. Its succulent stems can re-root where they touch moist soil, so pieces left after weeding can regrow, and it seeds prolifically to build a seed bank. Management is about controlling it very early — pre-emergence and early post-emergence herbicides and timely inter-cultivation before it carpets — and removing it cleanly.
How to identify it
- A low, fleshy, spreading (prostrate) summer weed with succulent, reddish stems.
- Small, fleshy, roundish leaves in unequal pairs, and small pinkish flowers.
- Germinates and spreads very fast after the first monsoon rains, carpeting the ground.
- Common in cotton, groundnut, soybean, vegetables and other kharif crops.
Why it is a problem
- Carpets the ground between young crop rows within days and competes hard for moisture, nitrogen, light and space.
- Can smother a slow-starting crop at the crucial establishment stage.
- Its succulent stems re-root in moist soil, so pieces left after weeding can regrow.
- Seeds prolifically and builds a soil seed bank, returning each kharif season.
Cultural & preventive control
- Control it very early — inter-cultivate/hoe as soon as it appears, before it carpets and seeds.
- Remove the weeded plants cleanly (do not leave stem pieces on moist soil, where they re-root).
- Grow a competitive, well-established crop and use proper spacing so it can compete.
- Prevent seed set and keep field edges clean to run down the seed bank.
Herbicide control
- Use recommended pre-emergence herbicides (e.g. pendimethalin) and early post-emergence herbicides for the crop, when the weed is small.
- Apply at the correct stage, dose and soil-moisture condition — early timing matters because it grows so fast.
- Rotate herbicide groups and combine with early inter-cultivation.
- Confirm the current herbicide, dose and timing for your crop with your local KVK.
Integrated management
- Combine timely pre-emergence herbicide, early inter-cultivation and clean removal with a competitive crop.
- Act fast after the first rains, since horse purslane carpets the ground very quickly.
- Prevent seed set every season to shrink the seed bank.
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 fleshy, fast-spreading weed carpeting my cotton/groundnut after the rains?
A low, fleshy, spreading weed with succulent reddish stems, small roundish paired leaves and small pinkish flowers, that carpets the ground fast after the first rains, is horse purslane (Trianthema portulacastrum). It competes hard with the young crop for moisture and nitrogen. Control it very early — pre-emergence herbicide (e.g. pendimethalin) and early inter-cultivation before it carpets — and remove the weeded plants cleanly, since its stems can re-root.
Why is horse purslane so damaging to a young crop?
Because it germinates and spreads extremely fast after the first rains, carpeting the ground between the crop rows within days, exactly at the crucial establishment stage. It then competes hard for moisture, nitrogen, light and space, and can smother a slow-starting cotton, groundnut or soybean crop before it gets going. That is why early control — a pre-emergence herbicide and prompt inter-cultivation right after the rains — is so important; once it has carpeted the field it is much harder to deal with.
Why must I remove horse purslane cleanly instead of just hoeing it?
Because its succulent stems can re-root where they touch moist soil, so pieces of stem left lying on the wet ground after hoeing can grow into new plants, undoing your weeding. So when you inter-cultivate or hoe horse purslane, remove the weeded plants from the field (or let them dry out fully) rather than leaving fleshy fragments on moist soil. Combine that with early timing, a pre-emergence herbicide, a competitive crop and preventing seed set.
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.