Comment by atourgates | Hacker News Reader

Comment by atourgates | Hacker News Reader

I've had pretty disappointing results with flame-weeding.

I live in a rural area in the Western US with some acreage, and try to avoid the use of herbicides as much as possible when I'm controlling weeds and invasives on our property.

Flame weeding is far and away the most fun and satisfying way to deal with weeds, but it doesn't seem to do much for me beyond perhaps briefly annoying them.

I've tried both near complete obliteration, and damaging the weed somewhat lightly under the theory that it'll expend its energy trying to "repair" itself, and die out more effectively in the long term.

Neither seems to work well with the thistles and other plants I'm fighting. I've even seen some thistles come back particularly strong after a fire. My theory is that seeds from competing plants are burned, but thistles underground network of rhizomes are unaffected, and take advantage of the lack of competition.

I recognize that fire is a natural and important part of the landscape and ecology of the West, but when it comes to crisping weeds, it seems to have limited use in my experience.

Fellow West Coast flame weeder here! Our weeds are especially tenacious, for the reasons you've described and for our boom/bust water cycles.

They tend to store enough excess carbohydrates in their roots to re-sprout three or four times. While this can make them seem utterly invincible, they will in fact deplete their resources if you stick with it long enough. I usually plan two or three flame weeds during spring, followed by some later touch ups if fire season allows. (Always wet the ground beforehand if it's dry out).

This also works with weed whacking. Himalayan blackberries, for instance, seem to only be able to resprout two times. So I knock them down as low as possible with a hedge trimmer, then touch up the new growth with the string trimmer about six weeks later, then again six weeks after that.

Weeds have evolved to have their leaves eaten and otherwise destroyed. Many rely on animals eating them to spread their seed.

You need some method to destroy the roots.

Fire is a great way to help restore soil. Some plants, as you found, come back stronger.

The best way I have found to get rid of weeds without herbicide is to make sure something else is growing on there.

Some weeds are pioneer plants. They come in on disturbed, and desolate soil. As they grow and thrive, they change the soil conditions so that other plants can grow there.

These plants are tenacious, but ironically, changes things so that they are out-competed by other plants. If you fight them, they dig in and get stronger. If you help them fulfill their ecological function, then they help make way for something else.

I keep trying to explain this to my father, who insists that mowing his entire noxious-weed-covered property is the only way to deal with them. Unfortunately, that's the only sure-fire way to keep them sticking around - scalp the soil bare 5x a year.

Thistles are usually a poor-soil indicator. Let them grow. They bring up nutrients from deeper underground. Then mow 'em down to mulch and you're improving the soil.

Most weeds regrow easily if you don't pull out their root structure.

There are adaptations against that, giving even greater tenacity and resilience. There are a whole bunch of plants that rhizomes. Attempting to pull out the root structure, in practice, helps propogate them via root division. Examples of such plants are running bamboo, kadzu, feverfew, bermuda grass, etc.

For these kinds of plants, it’s better to change soil condition: use a technique called “sheet mulching”; it delays things enough to establish a different soil condition and different plants. Even then, it may not work.

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