Allium triquetrum
I was introduced to this distinctive plant a couple of years ago by a friend. If you’re not familiar with it, the chances are you have passed it without even realising! Easy to identify due to the distinctive allium smell and the triangular nature of the leaves and flower stems, as indicated by both the common and scientific name (sometimes known as three-cornered garlic). It’s listed in Schedule 9 of the Wildlife and Countryside Act in England and Wales as a non native invasive plant, which means it’s illegal to plant or otherwise cause to grow in the wild.
However, if you happen to find it growing in your garden or out, it makes a delightful addition to soups or can be used in place of Spring onions.