A week or so ago my new friend Doug wondered about some gardening advice on the radio: would adding vodka to paperwhite narcissus make the flowers less “floppy?” The explanation he’d heard was that alcohol would burn the roots and reduce stem growth. Then today I received an email newsletter with the same intriguing information. This newsletter referred to a 2006 article that appeared in HortTechnology as the source of this information.
The study by Miller and Finan has generated a lot of interest in the gardening community, especially this time of year as people get ready to force bulbs for indoor blooms. Unfortunately, that enthusiasm isn’t evident among researchers. Neither the original authors nor any other researchers have continued this work; the HortTechnology paper has never been cited in any subsequent publication.
This is unfortunate – because inquiring minds want to know WHY alcohol causes narcissus stems to be shorter. Miller and Finan hypothesize that it’s simply an osmotic effect and allude to preliminary data that support this, “but additional work will be needed for confirmation.”
So I’ve looked into other scientific articles about ethanol and roots for insights into this phenomenon. There’s nothing on narcissus, but others have studied trees, forsythia, tomato and barley reactions to root-zone ethanol. In all of these cases, exposure to ethanol resulted in reduced root growth, decreased water uptake, and reduced leaf transpiration.
How does this translate to shorter stems and leaves? A reduction in water uptake and movement through the plant – that is, from roots through the stems and out of the leaves – can reduce movement of growth regulators like cytokinins from roots to stems and leaves. It can also mean that the plant contains less water and is less turgid as a result. Both growth regulators and cell turgidity are important in cell division and elongation. Reduced cell expansion will cause stems and leaves to be shorter and/or smaller as a result. This same phenomenon can be seen in plants grown under saline or droughty conditions: these plants are always smaller than their normal counterparts.
So what your grandmother used to warn you about is true – alcohol WILL stunt your growth!