Give it a try a little experiment and you might discover something positive

[Optimist]

I had always understood that white willow was the main source of salycetic acid, and also that it was contained in the layer directly under the bark. Salycetic acid is found in the bark of willow, birch and poplar trees, so willow is not your only choice. This does not adress the growth hormones which my untrained brain would think would be in the buds, but then wouldn't they be in the buds of all trees? Maybe this can be clarified.