Aspirin and Roses

jimofshermanoaks(9/21SoCal)October 11, 2011

Does anyone know of scientific evaluations of the use of aspirin to encourage plant defenses against pests and diseases? (I know there is a fair amount of anecdotal evidence, but wondered if there were intersubjectively transmissible data.)



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seil zone 6b MI

I've heard of this too but I don't know of any scientific studies on it, sorry.

    Bookmark   October 12, 2011 at 11:16AM
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the_bustopher z6 MO

I am currently trying aspirin therapy on my roses that have shown rose rosette disease and mosaic. So far the results look interesting, but I don't know what it all means yet or even if it is a permanent difference. I'll try almost anything at this point because actual help is better on my back than digging out bushes some of which are quite large and a couple of them are favorites.

    Bookmark   October 12, 2011 at 8:06PM
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kstrong(10 So Cal)

I have been trying to use the aspirin for quite awhile now. What I've learned is that you CANNOT get aspirin into solution -- it simply will not dissolve in water.

I've tried hot water, I've blended it in a Vitamix, I've used other things that might dissolve it first before I add it to the water. Nothing works. If you leave the resulting solution alone for awhile, you'll soon see the aspirin settle out to the bottom of whatever you put that solution in. And it will stay that way for a year (yes, I've even tried that).

If you spray with a sprayer and try to keep it in solution by just jostling it regularly, it will spot your leaves with whitish spots, that I presume are the aspirin.

Unless I come up with some new brainstorm, I am considering that experiment a failure (for now).

I do sometimes put a tablet or two in my pots however. Cain't hurt. But I can't say I've seen anything good from it either.

I don't know of any real controlled scientific studies anywhere though -- it just makes sense to me that it would likely work, IF you could get it into solution.


    Bookmark   October 13, 2011 at 12:36AM
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mike_rivers(z5 MI)

Kathy, the listed solubility of aspirin is 1 gram per 100 grams of water, which should be concentrated enough for any studies with plants. The metal salts present in hard water will react with aspirin to produce insoluble salts. Have you tried distilled water? Also, one aspirin tablet should dissolve rapidly, and stay dissolved, in a distilled water solution containing one teaspoon of baking soda.

    Bookmark   October 13, 2011 at 7:51AM
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kstrong(10 So Cal)

Well, I haven't tried distilled water, so maybe I should. Our local water IS known to be full of crap. Here's the current local water quality report for details: 2011 water report.

Thanks for the baking soda suggestion -- that's one I had not tried, but will. I did try soap and Indicate 5 and a commercial greenhouse spreader/sticker solution as potential emulsifiers, none of which did a darn thing to help. Since using distilled water would significantly increase the cost of my spray program, do you think the baking soda would take care of the issue with regular water??

    Bookmark   October 13, 2011 at 11:04AM
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mike_rivers(z5 MI)

Kathy, water hardness is reported as ppm calcium carbonate and water hardness greater than 170 ppm is termed "very hard". According to the water report in your link, the hardness for water in your area is either 270 or 605 ppm. Also, your water is alkaline - the pH is either 7.4 or 7.9. Aspirin is itself a mild acid. If you add aspirin to your alkaline water, the aspirin should form an anion which would then react with the metals which are in your hard water to form insoluble salts of aspirin. If you are treating yourself with aspirin, this is no big deal. The acid in your digestive system will redissolve the aspirin and your body can then deal with it as it chooses. But if you're treating plants, especially by spraying, the formation of insoluble salts of aspirin may present problems. I'm tempted to say that you will only need to spend the additional cash for distilled water for the time it takes to convince yourself that aspirin really does nothing. But, I won't. You might try making your water acidic with a few TBS of vinegar and then try dissolving the aspirin

    Bookmark   October 13, 2011 at 12:57PM
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kstrong(10 So Cal)

Thanks for that info. BTW, my understanding of the water sources here is that groundwater supplies most everything that comes through our tap, with LA's municipal water district there to supply the community's needs only during peak consumption periods. I think water usage is 100% groundwater in the winter and something like 75% groundwater in the summer, so our numbers are going to generally be the higher of the two values you mention in the prior post for hardness and alkalinity.

I do use Indicate 5 to bring down the alkalinity, and I put enough in to bring the pH to around the 5.3 pH mark on this Indicate 5 color chart. That has been my general practice for many years, as I have known that our water was alkaline and that spray chemicals tend to be more effective if that is not the case. But it didn't seem to help the aspirin problem.

    Bookmark   October 13, 2011 at 1:45PM
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The reason that aspirin does, or potentially does, have benefits to roses and other plants is that Aspirin literally is a natural plant rooting hormone, produced by plants. The chemical name for Aspirin is Acetyl-salicylic acid.

The genus name for willows, as you may very well know is Salix. Willows happen to contain very very high concentrations of Salicylic acid naturally, which is named for the willow genus. You may know that you can literally cut a branch off of a willow tree, jab it in the ground, ignore it, and it will root and grow another tree. Lucky for us, this plant hormone happened to be a pain killer and an anit-inflammatory.

We've been using aspirin for thousands of years, the ancient greeks and earlier civilizations used to chew on willow or make extracts. I'm guessing the main benefit of aspirin used on plants is strengthening of the root system (as it literally tells the plant to grow roots) thus increasing vigor, but may help the plant fight off diseases as well.

If you're interested in using a natural source of salicylic acid, and possibly more effective than aspirin, consider making some "willow water". Just cut off a number of young branches from a willow, chop em up, boil them with water. People even use this to root cuttings. It's a fun and easy project too. Just google willow water, you can find detailed instructions.

Well that's your history lesson for the day! lol.


    Bookmark   January 27, 2014 at 7:23AM
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albert_135(Sunset 2 or 3)

Based upon my memories of my undergraduate studies decades ago I would conjecture, and mind you it is only conjecture, that aspirin per se does nothing, but rather any benefit is from "salicylic acid" a breakdown product of aspirin. I believe @JetBonsai above has a good discussion.

ed-[Salicylic acid - Wikipedia - See 'plant hormone' second item under contents at this time]

This post was edited by albert_135 on Mon, Jan 27, 14 at 16:04

    Bookmark   January 27, 2014 at 11:55AM
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Albert is on the right idea. I guess I forgot to make it completely clear that aspirin is a derivitave of salicylic acid. In that aspirin was developed in the early 1900s basically by bonding an acetyl group to a molecule of salicylic acid. Hence the full name for aspirin is Acetylsalicylic acid!

    Bookmark   January 27, 2014 at 1:01PM
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Has anyone tried a liquid Asa solution? Or a mortar and pestle.

    Bookmark   January 27, 2014 at 3:17PM
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hoovb zone 9 sunset 23

You can buy Salicylic Acid in liquid form.

    Bookmark   January 27, 2014 at 3:28PM
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Plants have an immune system. The external application of Salicylic Acid (and its equivalent (in plants) aspirin) stimulates the immune system to become active.

The following quote is from the full review cited below. (The full review is not availble free.)
"Aspirin undergoes spontaneous hydrolysis to SA even in aqueous solutions (108). In blood plasma the hydrolysis of aspirin is catalyzed by nonspecific arylesterases (58, 109). Since arylesterases are found in most living tissues, it is reasonable to assume that in plants, as in animals, exogenously applied aspirin is rapidly converted to salicylic acid. This assumption is supported by the observation that in all studied cases the effect of aspirin in plants was similar to that of SA (see below). Many plant scientists have used aspirin and SA interchangeably in their experiments, despite the fact that aspirin has not been identified as a natural plant product."

Here is a link that might be useful: link for above

    Bookmark   January 27, 2014 at 4:07PM
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Also see:

Here is a link that might be useful: link for above

    Bookmark   January 28, 2014 at 5:32PM
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Title: "Effect of salicylic acid treatment on tomato plant physiology and tolerance to potato virus X infection"

Here is a link that might be useful: link for above

    Bookmark   February 27, 2014 at 11:38AM
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the_bustopher z6 MO

As for grinding the aspirin pills for making it part of my spray cocktail or even watering into the ground, I put them in a blender with some water and grind them into a solution. I then filter the inert insolubles out with a coffee maker filter paper and then make my dilutions to the concentration levels that I need. That helps prevent the insolubles from clogging my sprayer that I fight with on a regular basis.

    Bookmark   March 1, 2014 at 10:57AM
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