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10 common tropical weeds and their botanical names

Are you curious about the tropical weeds growing in your garden? You’ve come to the right place.

Here, we will cover the most common tropical weeds that thrive in areas with abundant rainfall and warm temperatures throughout the year.

You’ll be surprised to know that some of the plants considered to be weeds in these areas are highly valued as vegetables, herbs or used for ornamental purposes in other areas.

Here are the 10 common tropical weeds, including their botanical names, characteristics, and ways to eliminate them

1. Creeping foxglove – Asystasia gangetica

Creeping foxglove (Asystasia gangetica)
Creeping foxglove (Asystasia gangetica). Image: Wikimedia/Vengolis
  • Local names: Chinese violet
  • Family: Acanthaceae
  • Annual or perennial: Perennial
  • Grass, sedge or broadleaf: Broadleaf

Creeping foxglove, also known as Chinese violet, is a perennial herb that is native to Asia and Southern Africa.

When mature, the weed can grow up to one meter tall, with dark green leaves and a weak slender stem.

The best way to get rid of creeping foxglove is to use preventative measures to prevent it from spreading.

These methods may include physically hand-pulling the entire plant, especially by its roots, plucking seedpods and uprooting seedlings.

2. Witchweed – Striga Lour

Witchweed (Striga Lour)
Witchweed (Striga Lour). Image:
  • Local name: Witchweed
  • Family: Orobanchaceae
  • Annual or perennial: Annual
  • Grass, sedge or broadleaf: Sedge

Witchweed is a parasitic weed that attaches to a host plant to germinate and for early development. The weed originated from North Africa and Asia but has also recently spread to North America.

This perennial weed can grow up to 75cm, with rough green leaves and a thin stem. Witchweed is one of the tropical weeds with colorful blooms characterized by flowers which may be purple, white, yellow, bluish or a mixture of two colors.

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Apart from hand pulling, you can also eliminate witchweed by growing trap crops, improving soil fertility, crop rotation and planting resistant crop varieties.

3. Milkweed – Asclepias syriaca

Milkweed
Milkweed. Image: commons/wikimedia
  • Local name: Silkweed
  • Family: Apocynaceae
  • Annual or perennial: Perennial
  • Grass, sedge or broadleaf: Broadleaf

Named due to its milk-like latex when cut, Milkweed is a perennial flowering herb commonly found in Africa and parts of North and South America.

Milkweed originated from North America and Canada before spreading to other parts of the world. This poisonous weed can grow to about 1.8 meters tall, with simple green leaves and a cluster of pinkish-purple flowers. 

The most effective way to kill milkweed is by spraying herbicides, but you can also uproot the weed when still small.

4. Tridax daisy – Tridax Procumbens

Tridax daisy (Tridax Procumbens)
Tridax daisy (Tridax Procumbens). Image: Filo gèn
  • Local name: Coatbuttons
  • Family: Asteraceae
  • Annual or perennial: Annual
  • Grass, sedge or broadleaf: Broadleaf

Tridax daisy is a noxious weed native to tropical America, especially Mexico. This invasive weed can grow to reach 50 cm tall.

Tridax daisy has a hairy stem, oval-shaped green leaves, and daisy-like flowers on branching stalks.

A single daisy plant can produce up to 1,500 achenes, easily spread by wind.

Professional application of herbicides effectively eliminates tridax daisy, although other methods, such as hand-pulling and mowing, can also work.

5. African club moss – Selaginella kraussiana

African club moss (Selaginella kraussiana)
African club moss (Selaginella kraussiana). Image: Wikimedia/Kenraiz
  • Local name: Krauss clubmoss
  • Family: Selaginellaceae
  • Annual or perennial: Perennial
  • Grass, sedge or broadleaf: Broadleaf

Characterized by fern-like evergreen leaves, African club moss is a perennial weed naturally found in Sub-Sahara Africa. It is a low-growing plant, which barely exceeds 5 cm tall.

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African club moss weed spreads quickly through rooting stems and can be challenging to eliminate.

Therefore, applying herbicides properly and early is advisable, but uprooting the young plant can also help.

6. Bermuda grass – Cynodon dactylon

Bermuda grass
A Bermuda grass lawn
  • Local name: Bahama grass
  • Family: Poaceae
  • Annual or perennial: Perennial
  • Grass, sedge or broadleaf: Grass

Bermuda grass is considered a valuable fodder crop. It is a hardy perennial grass that can withstand prolonged drought seasons.

The grass originated from the Indian Ocean basin stretching from East Africa to India.

Bermuda grass spreads fast via its stolons and can be stubborn to eliminate. However, using approved herbicides or pouring boiling water on the grass can aid in killing the grass’s roots.

We’ve previously covered ways to eliminate weeds from Bermuda grass should you wish to use the grass in your lawn.

7. Siam weed – Eupatorium odoratum

Siam weed (Eupatorium odoratum)
Siam weed (Eupatorium odoratum). Image: Wikimedia/Vengolis
  • Local name: Devil weed
  • Family: Asteraceae
  • Annual or perennial: Perennial
  • Grass, sedge or broadleaf: Broadleaf

Siam weed is another common tropical weed that is native to Central America. This perennial weed can grow up to 10 meters tall in shady areas.

The weed has green leaves that produce an aromatic odor and white-pinkish flowers.

A single Siam weed can produce over 80,000 achenes containing seeds that spread via wind.

You can get rid of the weed through the application of licensed herbicides and pulling it at the roots.

8. Carpet grass – Axonopus compressus

Carpet grass – Axonopus compressus
Carpet grass – Axonopus compressus. Image: Flickr/macleaygrassman
  • Local name: Carpet grass
  • Family: Poaceae
  • Annual or perennial: Perennial
  • Grass, sedge or broadleaf: Grass
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Native to the Americas’ tropical and subtropical regions, carpet grass is one of the tropical weed species distinguished by its two-edged seed head.

This perennial grass thrives in warm climates and can easily suppress other crops.

Hand-pulling can be effective in cases where the grass is not widely spread. In other cases, you may need to use herbicides or burning with boiling water to get rid of this weed.

9. Nutgrass – Cyperus esculentus

Nutgrass (Cyperus esculentus)
Nutgrass (Cyperus esculentus). Image: Wikimedia/jroldenettel
  • Local name: Tiger nut
  • Family: Cyperaceae
  • Annual or perennial: Annual and Perennial
  • Grass, sedge or broadleaf: Sedge

Nutgrass, also called tiger nut, is one of the weeds in tropical regions that are both perennial and annual plants.

The invasive weed can grow up to 90 cm tall with triangular stems and fibrous roots with nut-like tubers.

Tiger nut can produce as many as 2400 seeds in a single plant, spreading quickly. A common natural method for eliminating nutgrass is to pull it from the roots.

But for a more effective solution, consider applying herbicides.

10. Couchgrass – Elymus repens

Common couch (Elymus repens)
The common couch grass. Image: Flickr/John Tann
  • Local name: Common couch
  • Family: Poaceae
  • Annual or perennial: Perennial
  • Grass, sedge or broadleaf: Grass

Lastly, we have couchgrass, a perennial grass native to Africa, Europe and Asia. This grass can grow up to 50 cm tall and has root stalks that aid in rapid spreading and thin hairy leaves.

Couchgrass is a very invasive weed as its root stalks can entangle around the roots of crops. It is, therefore, good to lightly pull the weed from the loose ground or dig deep to remove the grass.