Dear Readers, when I was growing up my Mum would always pop a soluble aspirin into the water if she received some cut flowers – this was a very rare occurrence, and so she wanted to make them last as long as possible. But is there actually any evidence that it helps? In New Scientist last week, James Wong went through the science, and very interesting it was too.

As you probably know, aspirin (acetylsalicylic acid) is derived from a naturally occurring plant compound, salicylic acid – willows, or Salix, are named for this chemical. In humans it acts as a painkiller, but in plants it acts as a signal that some kind of damage is imminent, through drought, pests or some other threat – Wong describes salicylic acid as a kind of ‘on/off switch’ for the immune system.

Studies have shown that if plants are misted with aspirin, their own defences ‘ramp up’, and this treatment also seems to improve the quality of harvests: one experiment showed an increase in the Vitamin C in tomatoes, while another study showed spraying cherries made them larger, with a higher antioxidant content.

However, the one thing studies haven’t shown is that putting aspirin in to plant water makes the flowers last longer. When compared with pure tap water, there was no difference in the longevity of chrysanthemums or roses. What does seem to make a difference, empirically at least, is a) not having your flowers in a room that’s very warm, b) not keeping your flowers in the kitchen (probably because of proximity to fruit like bananas, which exude ethanol as they ripen – this encourages other fruit and flowers to hasten through their life cycle too), and c) change the water every few days. Let me know if you have any ‘hacks’!

Tiny cucumber spider on cut lilac!