Once in a while, I see a critter that I don’t believe is real. The common emerald (Hemithea aestivaria) is such a creature–a spectacularly beautiful and intricately accessorized moth that showed up on our porch one evening.
The common emerald is not a native moth; it was accidentally introduced to British Columbia in 1973 and has been spreading gradually across North America since then. It has a large natural range, including the Nearctic, Palearctic, and the Near East, and is most common in the southern half of Ireland and Great Britain.
While the hope in planting native flora is to improve habitat for native fauna, a side effect for me has been learning more about non-native fauna (and there is more of it than you might think!). While I try to eradicate invasive plants from my yard, I still have respect for non-natives. They are amazing species in their own right, and it is their admirable ability to succeed away from home that makes them a challenge.
Common emeralds have a wingspan of around 1.25 inches. They are on the wing in early summer (June/July).
While I will not be planting flora to feed common emerald larvae, it turns out they have a broad menu of host plants, from Aralia to Viburnum, with dozens of species in between. Many of those host plants are already in my garden.
I only see one or two of these moths each year. Each sighting fills me with joy and wonder! As the name suggests, this critter is a real gem.
