"Franz Heymann" wrote in message ...
If you Google on "aspirin rooting" or "salicylic acid rooting" you will come across a large number of cases in which aspirin and
willow bark extract are discussed in the context of rooting agents. Unfortunately all the entries I found are either
qualitatively anecdotal or second-hand reports.

Exactly. We need to see the papers if they exist.
As to rooting powders as found in garden centres - this stuff has virtually zero shelf life and is therefore almost certainly
worthless at point of sale. The fungicide content may provide a marginal benefit. I have seen reports of trials and research on
hormone rooting substances over the years clearly demonstrating efficacy when using freshly prepared hormones under well controlled
conditions, but these are not conditions available to most gardeners. The good news is that the vast majority of subjects root
perfectly well albeit less quickly without rooting compounds. Much more important - and the area that causes most failures is
failing to prepare plants to produce good cutting material and then in correct choice of cutting material. Compost, control of
light, water and temperature are all important but useless if you don't get decent cuttings in the first place.

Rod