Hagonoy Eradication Project

There are weeds, and then there are BAD WEEDS. Hagonoy or Chromolaena odorata is a globally invasive species that is “regarded as the worst alien invasive plant species in the subtropical regions of South Africa” and has been nominated as one of the 100 of the “World’s Worst” invaders. It is also known as Siam Weed, Christmas Weed, and Jack in the Bush. I was surprised to find out while we were in Cambodia that hagonoy has a beneficial use. In Cambodia, they crush it and apply it to wounds.

After years of mostly ignoring the hagonoy, I decided to be the chief implementer of the Hagonoy Eradication Project! Hagonoy has a main tap root that is somewhat shallow. As the plant gets bigger, the side roots spread out sideways. For effective hagonoy removal, you need to pull up the entire plant including the roots. If you leave some of the roots behind, the plant will just sprout up again. The small hagonoy plants are easy to pull out, but they tend to have stems that break off easily when you pull them. The bigger plants have many stems branching out from the root, making the plant harder to grasp and pull out.

I tried several sessions of pulling out hagonoy using just my hands, a small screwdriver-type weed removal tool, and then a big crow bar. It was exhausting! I could only last for 1 hour removing the bigger plants with a crow bar. I needed to buy better tools!

small hagonoy plant
small hagonoy plant
the root of a big plant
the root of a big plant

I wanted to buy tools that would allow me to:

  1. Remove the entire plant including the roots.
  2. Save my hands so I can sketch and paint!
  3. Save my back.
  4. Exert less effort so I can do other things with my day aside from eradicating hagonoy.

I figured that one tool wouldn’t be able to suit every weed situation. Some hagonoy grow in tall grass, some in the open, some are big bushes spread out in a field, some look like many medium sized plants forming a low bush. I couldn’t find any articles describing the best tool for removing hagonoy by hand. I read a lot of tool reviews that mostly described North American weeds and bought 5 different tools online that looked like they would work on hagonoy. It seems like a lot, but it was also my birthday month when I was tool buying!

I bought 2 hand tools and 3 standing up tools.

The 2 hand tools L-R: Japanese Hori Hori Garden Stainless Steel Blade and Sheath, CobraHead Weeder and Cultivator


The 3 standing-up tools from L-R: Radius Garden 205 Pro Ergonomic Stainless Steel Weeder, CobraHead Long Handle, Grampa’s Weeder


I was so excited to try out my new tools!


Tools packed up and ready to go! See the hagonoy on the right and in the background?
Tools, water, and snacks packed up and ready to go!


The Most Fun to Use – Grampa’s Weeder!
This tool is amazing! You drive down the tines into the middle of the weed by stepping down on the lever,  lean the handle towards the lever, and the weed effortlessly pops out! Downsides are 1) if you do it wrong, the stem breaks off and 2) the tines can only fit a limited size of stem. The tines are too small to handle big plants.

Coolest Name – Hori Hori Knife!
This knife feels great in the hand. One edge is sharp, the other edge is serrated, and the blade is curved. Based on my limited use, it looks like it will be very good for removing the small weeds without snapping the stems off.

Not Working So Far – the two CobraHeads!
I need to figure out these tools. So far, they are not working well. I think it might be our sticky, clay soil. You are supposed to drive the tip behind the weed and then pull it towards you. The tip of the tool is supposed to work like a big, metal fingernail. Maybe it will be good for other kinds of weeds or in other types of soil.

Most Awesome Hagonoy Remover – the Radius Garden 205 Pro Ergonomic Stainless Steel Weeder!

This is the least sexy looking of the bunch. It looks like a shovel. It is amazing and better than a shovel because it has a 100% success rate with surprisingly low amount of effort! It gets the root out every single time. It does not fail. You plant the tip next to the weed, drive it deeper at an angle by stepping down on the “wings” with your foot. No need to use your hands to press down. Then when you see the weed start to wobble you press down on the handle and the entire plant topples over. It is so quick, easy and satisfying to see. You will feel like shouting “timber!” in a gleeful voice! The main disadvantage of this tool is that it brings out a big ball of dirt with the roots and leaves a big hole in the ground. You can minimize this by finessing the leveraging technique.

big ball of dirt
big ball of dirt
by the 2nd day, I didn't bring the other standing-up tools
by the 2nd day, I didn’t bring the other standing-up tools

It’s also essential to use a good pair of gloves. I am very happy with these Mechanix Wear synthetic leather work gloves.


I’m very happy with my new weeding tools! Yep, this is what I do for fun. Hagonoy, your days are numbered!



9 thoughts on “Hagonoy Eradication Project”

  1. Dear Sylvia,
    Hagonoy has a very important role in restoring our ecology. Because it is avoided by animals, it thrives and provides moisture to the soil. That moisture allows seeds that were just waiting for the right moisture to come out from hibernation. That is how plants and trees endemic to the area get a chance to grow again.
    All best,

    1. Hi Vic!
      Thanks so much for this comment. I hadn’t thought of it that way. I can see how it.s better to have hagonoy than bare soil. When there are many animals grazing though, the hagonoy ends up dominating the area. Seedlings don’t have a chance to grow because they are easily overwhelmed by the speedy growth of the hagonoy. In the areas where we remove the hagonoy, we see a good variety of plants and trees sprouting up in the area. I’m trying to boost the chances of those other plants by removing the hagonoy and also by removing the grazing animals. We don’t have any cows, carabaos, or goats. Only 2 horses. I think that the hagonoy spread in our area when the previous owners cleared the trees for firewood and then used thr land for grazing animals. A lot of the areas were over-grazed.

  2. Thanks for the tool recommendations, Sylvia! I plan to buy and try the the Radius Garden 205 Pro Ergonomic Stainless Steel Weeder on this invasive climbing rose vine in my small garden. This rose vine is something I have been wanting to completely remove for many years. It has roots that are underground spreaders about 6″ deep which break easily if pulled by hand. I don’t want to use chemicals to kill the weeds so I’m always on the hunt for a better tool.

    I have the Hori Hori knife too which is very useful for planting, cutting roots from a potted plant, and small weeding jobs. I also have the cobrahead weeder hand tool and you are right, it does not work well with hard clay soil so I hardly use it. It’s ok for loose garden soil and shallow rooted weeds.

    I’ll let you know if it works on my rose vine. What was the longest depth of the Hagonoy roots you have seen so far?

    1. I hope it works well for you. When I made our caretaker Picio try it, after he pushed it into the soil, he was able to sort of hook the tip of the Radius Pro on the hagonoy and pull it out without disturbing the soil as much as when I use it. I think there are different techniques possible, especially if you’re used to gardening and are familiar with how the roots grow. I’m interested to hear how it works on your rose vine!

      The habonoy doesn’t go very deep. The deepest is probably less than a foot. It can grow very long sideways roots.

  3. Hi Sylvia! I finally bought the Radius Garden 205 Pro Ergonomic Stainless Steel Weeder online to use in my small garden on morning glory type of weeds that grow like vines with 6 inch or longer roots. Thanks for recommending this tool on your blog. I was able to push it down on the soil using my feet and dig up the roots with a few twists and without bending. It was worth the price to be able to pull this tough weed faster with more precision, and less labor. These weeds grow back every spring and summer when we used to just pull it by hand. Now that I can dig deeper with the roots intact, I hope next year’s weeds are much less. I will try it on the rose vine next. Thanks again!

    1. Hi Arlene! Yey, I’m glad that it worked for you. It is still my favorite tool of all. It will be interesting to see if there are much less weeds next year. Crossing fingers! I get a really good workout when I use the weeder, I consider it a bonus! Haha!

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