Willow water

[John85]

How good did it work for you? What recipe do you use?
There are several on the web :with cold water ,boiling water,infuse for a few days or several weeks.
Also not precise : how big is a handful?Depending on the size of the hand concentration can vary by 100% or even more!
Till now it was not successful for me.I use twigs of Salix caprea
On the web they say it only works for species easy to root and that it is not as good as chemical hormones.I use it to root several Hebes.

[Alan_b]

I have been told that aspirin is a good substitute; the active ingredient is derived from willow trees.  I have tried aspirin when I am particularly keen to ensure rooting and I have had some success, although certainly not 100%.  I cannot say whether the aspirin made any difference.

I should add that the gentleman who told me about the use of aspirin was Timothy Clark, a really expert plantsman with a garden full of old cultivars, some of which that may not exist anywhere else.     

[Anders]

Aspirin contains acetylsalicylic acid, that is a derivative of salicylic acid found in willow (Salix), but acetylsalicylic acid is not the active compound in rooting.  For rooting, you need a plant hormone from the group of auxins so that you get a high auxin to cytokinin ratio in the cutting (a low ratio by adding cytokinin instead of auxin will induce shoots). All plants produce these hormones but in different concentrations. It is likely that willow has increased auxin levels, at the least they are very good at making roots. I found this recipe that looks reproducible though I haven't tried it, I use the synthetic stuff.

https://www.hunker.com/13427967/how-to-make-a-rooting-hormone

Anders

[Rick R.]

I contend that if willow water works in any way at all, it would be because of the presence salicylic acid, rather than any auxins.  Auxins that are steeped from willow would be at an incredibly tiny concentration.  Of course, only a tiny amount is needed, but just think about the tiny amount that would be inside the cells, and then only a fraction of that gets steeped into water that is a million times and more the previous volume that was inside those compromised cells.  Where could such an enormous dilution rate be valuable?

   But the salicylic acid is what is absent in other applications and I could see it that might make a difference. There are scientific papers that document its effect on plant cells.  None that I know of that connect to any rooting results, but a certain kind of cell stimulation is real, and that might have a roundabout effect.  I wish I could be more specific, but that was so long ago that I looked into this.

The whole question of willow water usage is often brought up in forums, etc, and I always offer the same challenge:
Don't show me anecdotal info or claims, show me factual data with even a modicum of science in it.  I never get any replies.

All this said, I would never completely dismiss the subject, unless I see science disproving it also.

[Anders]

There is no doubt that salicylic acid is a plant hormone with many different effects, but mostly associated with pathogen defense mechanisms. I would not use aspirin as the active compound acetylsalicylic acid may actually do more harm than good, see this quote from a research article: “Here, we provide evidences that acetylsalicylic acid also behaves as an agent inducing programmed cell death (PCD) in cell cultures of the model plant Arabidopsis thaliana” (Reference: PLANTA, 2008, Volume: 228  Issue: 1,  Pages: 89-97, DOI: 10.1007/s00425-008-0721-5)

Anders