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  #1  
Old 05-18-2010, 06:50 PM
Darryl Lict Darryl Lict is offline
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Will Roundup kill my palm tree

I've got a couple of magnificent palms that look kind of like a Canary Island Date Palm. There are weeds growing in the bark of the trees. Can I spray Roundup on the weeds without killing or otherwise damaging the palm trees?
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  #2  
Old 05-18-2010, 07:30 PM
Colophon Colophon is online now
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Round-up gets absorbed through the leaves of plants and transported to the roots. It quickly breaks down in the soil, so it shouldn't damage plants that are simply growing near the weeds (as long as you make sure you only spray it on the leaves of the weeds).

If the weeds are actually growing in the bark of the palms, though, I wouldn't risk it.
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Old 05-18-2010, 10:54 PM
CookingWithGas CookingWithGas is offline
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Roundup is not effective against woody plants. It is not too good against poison ivy, f'rinstance. However, this business of weeds growing in the bark of palms is a bit unusual (to me, anyway). I would try weed killer first (something like Weed B Gon) rather than a defoliant. It's not urgent so I would use the most benign, low-risk approach first. A lawn & garden shop where you can buy the stuff should be able to advise you.
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Old 05-19-2010, 05:54 AM
Blake Blake is offline
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Quote:
Originally Posted by Darryl Lict
Can I spray Roundup on the weeds without killing or otherwise damaging the palm trees?
Provided that the bark isn't broken and the soil isn't very sandy, you're safe.


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Originally Posted by CookingWithGas View Post
Roundup is not effective against woody plants.
Palms are not woody plants. Glyphosate will kill them readily.

Quote:
However, this business of weeds growing in the bark of palms is a bit unusual (to me, anyway).
Not so much the bark as the remains of the leaf bases. It's very common in wetter climates.

Quote:
I would try weed killer first (something like Weed B Gon) rather than a defoliant.
Glyphosate is a weed killer, not a defoliant.

Quote:
It's not urgent so I would use the most benign, low-risk approach first.
Glyphosate vs. a cocktail of Dicamba, MCPA and 2,4-D. I know which one is lowest risk, and it ain't Weed B Gon.
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  #5  
Old 05-19-2010, 07:00 AM
johnpost johnpost is online now
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roundup will kill woody plants if applied to leaves, green bark or fresh cuts in the wood. this is dose dependent, a woody plant with a large root will take many applications. roundup doesn't penetrate hard bark.
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  #6  
Old 05-19-2010, 07:32 AM
Blake Blake is offline
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Originally Posted by johnpost View Post
roundup will kill woody plants if applied to leaves, green bark or fresh cuts in the wood.
It might kill some species if applied in that manner. For many more species it will produce abnormalities in growth and little more. The mode of action of glyphosate makes it less than ideal on plants with woody tissue. It's not the size of the root system per se, it's the amount of growth going on throughout the plant.
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Old 05-19-2010, 08:17 AM
johnpost johnpost is online now
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Originally Posted by johnpost View Post
roundup will kill woody plants if applied to leaves, green bark or fresh cuts in the wood. this is dose dependent, a woody plant with a large root will take many applications. roundup doesn't penetrate hard bark.
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Originally Posted by Blake View Post
It might kill some species if applied in that manner. For many more species it will produce abnormalities in growth and little more. The mode of action of glyphosate makes it less than ideal on plants with woody tissue. It's not the size of the root system per se, it's the amount of growth going on throughout the plant.
the larger the root, the larger the plant, the more growth that needs to be inhibited; also the agent is spread through more tissue. in lower doses it does produce abnormal growth, it will do this on weeds as well. it is much more effective on emerging plants because of its inhibition on new growth, on mature plants it takes longer to affect new growth.
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  #8  
Old 05-19-2010, 09:17 AM
kunilou kunilou is online now
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It's unlikely that you will apply Roundup in a high enough volume or concentration to kill a mature palm tree. However, any plant that you describe as "magnificent" deserves better protection than "unlikely." Try a non-herbicidal approach first.
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  #9  
Old 05-19-2010, 11:33 AM
Wile E Wile E is offline
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I had a weed palm growing in a very inconvenient spot. I applied a tree killer to it, a few of the fans fell off but it survived. I had to take a saw and lop off the top and paint it with tree killer twice before it died. IME palms are hard to kill even if you're trying to kill it but I don't know how delicate your palms might be, mine was one of our native palms that sprout up everywhere.
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  #10  
Old 05-20-2010, 03:47 AM
Blake Blake is offline
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Originally Posted by Wile E View Post
I had a weed palm growing in a very inconvenient spot. I applied a tree killer to it, a few of the fans fell off but it survived. I had to take a saw and lop off the top and paint it with tree killer twice before it died.
See, there's your problem. Tree killers are designed to kill broad leafed plants. Palms aren't broad leafed plants, and are therefore largely unaffected by many aboricides. You would have been better off using glyphosate.
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  #11  
Old 05-20-2010, 11:52 AM
Wile E Wile E is offline
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Originally Posted by Blake View Post
See, there's your problem. Tree killers are designed to kill broad leafed plants. Palms aren't broad leafed plants, and are therefore largely unaffected by many aboricides. You would have been better off using glyphosate.
Well, I couldn't find anything that said it killed palms. I even asked at a nursery, since I also had some Brazilian Peppers that needed to die I figured I would try that stuff out on the palm, too. Like I said I had to cut the palm way back a couple times. I would think you'd need a heck of a lot of roundup to take out a full sized palm.
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  #12  
Old 05-21-2010, 03:31 AM
Darryl Lict Darryl Lict is offline
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Thanks for the answers. I'll try a more benign approach, like pulling out all the damn weeds. Grrr!
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