Willows (salix spp) are famed as the precursor of aspirin and other pain relief medicines due to their content of Salicylic acid which works by inhibiting the production of those prostaglandins that sensitize nerve endings to pain.
Within plants containing Salicylic acid, they use the compound/hormone to signal a plant’s defences and induce resistance to pathogens. I love the signal bit as it extends beyond the affected plant and warns all in the vicinity by converting some of its salicylic acid into a volatile chemical form and it wafts the ‘danger’ signal on the air to the receptors of its neighbours. A beautiful act.
An old florist’s trick to extent the vase-life of cut flowers is to add an aspirin to the water, it does perk up plants but the science behind it lies in the properties of Salicylic acid to trigger defence and healing. It is a tip we could borrow to deal with damping off and help increase strike rate (success with cuttings). We know that one of the biggest threats to recently propagated cuttings is loss by infection from bacteria and fungi, something that the natural Salicylic acid in willows can ward off … but it is not just a preventative I am after, Willow also contains Indolebutyric acid, a plant hormone that stimulates root growth, so the combination of defence and rooting is ideal for headache free cuttings.
So how do you make it happen?
Simple. Gather some willow sprigs/foliage as both the Salicylic acid and Indolebutyric acid are present in high concentrations at the growing tips of willow branches. Cut and slice to allow the active principles to leach out into a solution of cold water. Add to cold water and steep/ferment for 3weeks.
Alternately make a decoction with boiling water and chopped plant parts – to sit over night for next day use.
Either method – do sieve away the plant material and utilize the strained liquid as both a hormonal rooting agent and a compost/cutting medium sterilizer.
I find it works best with cuttings that you would normally stand in water to root. The success rate is speeded up and amplified.