DIY Life

I'm a green gardener. I'm loathe to use toxic chemicals in my yard. However, there are certain situations when only toxic will do. Like, for example, when I recently had to kill a tree. Read on if you're in the same boat and would like some tips. Oh, and be sure to check out my photo gallery, too!

The Camphor Laurel: An Invasive Pest

First up: a bit about the tree in question. The offending plant was a camphor laurel tree (cinnamomum camphora), a native of East Asia that has become an invasive pest here in the US and in other countries, like Australia. Yes, this plant is the source of stinky camphor oil, which is found in products like Vicks® cold remedies.

In my backyard, the camphor is a big pain-in-the-butt-plant. My nemesis. My arch-enemy. It self-sows everywhere. I must have pulled hundreds of tiny seedlings by hand since learning (the hard way) to be more vigilant. Hand weeding camphor seedlings is a nuisance, but it sure beats trying to eradicate them once they become established.


The camphor has an unusual root system that makes it hard to dig out once seedlings have grown larger than about one foot in height. Camphor saplings have one main root shaped a bit like a carrot that burrows deep, deep down into the soil. Removing them without chemicals involves a lot of backbreaking digging, usually accompanied by much cursing. (As I say, I learned the hard way to be more vigilant!)

Not sure if you've got a camphor tree? They're easy to identify. Camphors grow fast and they grow tall (50-100 feet). They are evergreens with small, glossy green leaves. Crush the leaves, or fell a tree, and you will smell the unmistakable odor of camphor. Not sure? There are tons of photos of this plant available online.

Yes, camphors are pretty and make good shade trees. But so do hundreds of other trees and larger shrubs. If you have one, take my advice and kill it, then replace it with something more environmentally friendly.

Interesting to note: wood-turners may be interested in your felled camphor tree. Apparently, it's a good wood for carving.

How to Kill A Camphor Laurel (or Any Pesky Weed Tree)

So you want to kill a tree? Herbicides are necessary for the job. Any weed tree, once cut down, will just re-sprout from the stump. This is especially true of an invasive species like camphor, which regenerate with a vengeance after being cut or pruned. Please: don't waste your time and energy trying to trim them!

Step 1: cut-stump application: the best method for most homeowners
How big has your weed tree become? Is it near or far from any buildings? If it is still smallish -- with a trunk only around 10 cm diameter -- and far from your house, you can spray the entire plant with a herbicide without cutting it down first. This is known as foliar application.

Or you can try basal bark application, in which the herbicide is applied to the base of the trunk. Either way, the dying tree can be left standing, to break down slowly over time.

If the tree is larger, or if it is anywhere near your home or within view of the street, you'll likely want to cut it down first, then kill the root system by painting the freshly cut stump with herbicide. This method, called cut-stump application, is the one that I used. Just remember: herbicides must be applied to a freshly cut surface.

If, like me, you're trying to be a green gardener, you'll also prefer the latter method -- applying herbicide directly to the cut stump -- because it's easier to restrict what the chemical touches and kills.

Step 2: pick a poison: glyphosate vs. triclopyr
Two herbicides are commonly used to kill unwanted trees: glyphosate and triclopyr.

Glyphosate is the best known herbicide out there, sold under the ubiquitous brand name Roundup®. Glyphosate is nonsystemic, meaning it kills whatever it touches. It's popular for that reason, and also because it becomes inactive fairly rapidly in the soil, so the affected area can be replanted within only a day or so.

Your other option for killing trees is triclopyr, commonly sold under the brand name Garlon®. Triclopyr is a systemic herbicide that kills broadleaf trees and shrubs, and is particularly effective against waxy-type trees like camphor.

Again, we come back to the question of green gardening. Which is friendlier to the environment: glyphosate or triclopyr? Well, that's up for debate, and depends quite a bit on how you use your chosen product. Yes, it's true that glyphosate is nonsystemic, whereas triclopyr kills only broadleaf plants -- leaving grasses, for instance, unaffected.

On the other hand, if you apply glyphosate with care -- painting it directly onto specific surfaces or spraying it very carefully -- you won't do much harm to surrounding plants. Another plus: glyphosate becomes inactive and breaks down fairly quickly. That said, it's hardly environmentally friendly to use any type of herbicide, and the perception (and marketing) of glyphosate as a more or less environmentally responsible herbicide is hotly opposed by environmentalists.

Bottom line: a poison is a poison, period. Use herbicides only when you absolutely must and not for day-to-day control of common weeds in and around lawns and paths.

While we're on the subject of consumer education: for a handy rundown of complications and dangers associated with using herbicides on trees, check out the list of tips in this article from About.com. Particularly worth noting is the observation that root grafting can occur between plants of the same species and, sometimes, the same genus. Therefore, treating one with herbicide may mean the inevitable death of another, desirable tree nearby.

Herbicide concentration is another factor that must be considered. You will need to use a fairly highly concentrated form to kill something large like a tree. The ready-to-use containers of Roundup® commonly sold at big box stores are designed to kill weeds, and are not powerful enough for this tree-killing project.

Ideally, you should use a 50% solution if you opt for glyphosate. That's Roundup® Super Concentrate, if you go with that brand. (I have to confess, I balked at the cost of a bottle of the Super Concentrate and chose to go with the less powerful Concentrate Plus. I'm crossing my fingers and hoping it works, because I will tear my hair out if this camphor tree stump starts sprouting again!) If you choose triclopyr, try a 40 or 50% solution in oil.

Step 3: assemble your tools
This is a task that calls for warm, dry weather. Wear long pants with socks and boots, and a long-sleeved shirt, to protect your skin from accidental chemical exposure. You will also need:
* a saw or chainsaw
* work gloves
* eye protection, especially if you are using a chainsaw or herbicide spray gun
* herbicide
* electric drill or hammer and large nail
* paintbrush
* broom or small brush
* hand pruners or long-handled lopers
* a rag in case of spills
* a bucket

Step 4: execution time for a tree stump
The thing to remember when killing a tree is that time is of the essence if you are applying herbicide directly to the tree stump. To be effective, the chemical must have time to soak into the exposed trunk before the plant releases sap that seals the cut surface.

Apply herbicide to the entire stump if it is only small (around three inches or so in diameter). If the tree stump is a large one, it's not necessary to apply herbicide to the entire stump surface. The outer two or three inches will do the trick, because that's the living wood. The inner wood, the heartwood, is actually already dead.

First task: Don your gloves and eye protection. Use your hand pruners or lopers to cut off any saplings or suckers sprouting directly out of the tree. Using a paintbrush, apply herbicide directly to the cut surfaces.

Tip: Here is where the bucket comes in handy: keep your bottle of herbicide in it to help it stay upright and to prevent spills.

Second task: Fell the tree using a saw or chainsaw. Obviously, felling a larger tree will require helpers or even expert assistance. Don't attempt this step unless you're sure you can handle it! If your tree has previously been felled, you will need to cut the stump through again as low as possible to the ground. This will leave you with a nice, freshly exposed surface on which to apply the herbicide.

Tip: It's tricky to do this, especially if you don't have a chainsaw, but try to cut on a level. That way, the herbicide is more likely to pool effectively on the stump instead of running off... onto desirable plants... or your shoes.... Oops!

Third task: Depending on the size of the stump, drill one or a few holes into the cut surface. If you don't have a drill handy, a hammer and nail do the job just as well. Use your broom or brush to sweep away the sawdust. Herbicide will pool inside the holes and hopefully improve its effectiveness. Do this speedily, before the tree has a chance to send much sap to the cut surface.

Fourth task: Using your paintbrush, apply herbicide directly to the stump, focusing on the outermost two or three inches of wood and on the holes made by the drill or nail.

Tip: to apply herbicide, use an old paintbrush, or do what I did and purchase a cheapo paintbrush especially for the task. The one I used cost only 75 cents, and having it meant I didn't have to worry about rinsing a good paintbrush clean.

Well, you're done!

Hopefully, this will spell the end of your pest tree, whether it be a camphor laurel or something else. Now it's time for the enjoyable part: deciding what to plant in this newly-vacated space. Of course, you can plant around the remaining dead stump. Alternatively, if you're willing to wave goodbye to some lovely cash, hire a stump-grinding service.

Finally, replace your weed tree with something that's friendly to your local environment. Consider a native species or perhaps something with berries and flowers that attract birds and insects. Check and see if your state government has published a friendly plants list for your area, like this fab online database for Florida residents.

Happy planting!