I came across two recipes online for a 'shrub' in a week, so I saw it as a sign that I needed to (A) learn what a shrub was, and (B) to make some at home. I soon learnt that shrubs are a vinegar-based simple syrup that was originally made as a way to preserve fruit for the winter. Shrubs have been enjoying a comeback lately (I think predominately in the US) as people are looking back at the cocktail 'classic' recipes from decades ago.
10 ripe peaches, pitted and chopped
1/3 cup Peach Shrub
2 shots Vodka
Chilled Soda Water