Vines (Muin) with their interlocking stocks were signs of interconnectedness, eternity, and diversity to the Celts (by the way the ancient Celts viewed any plants with woody stocks as Trees and this particular Vine was probably the blackberry).
The Ogham symbol for “M” (Muin) in our alphabet appears in the accompanying graphic. Messages starting with this letter conveys a sense of connectedness and perhaps protection (the thorns on blackberries) depending upon the context.