Last month along the Panhandle Trail I paused to look at a wildflower near some Japanese knotweed when I noticed the knotweed was being eaten by Japanese beetles.  🙂

Japanese beetles (Popillia japonica) were introduced to North America by accident in the early 1900s and spread across the continent.  The adult beetles eat leaves, the larvae eat roots.  If you have roses, you’ve been battling Japanese beetles your entire life.

Japanese knotweed (Fallopia japonica) was introduced as a garden plant but is so aggressive that it chokes out native plants and even grows through asphalt.  As one of the world’s worst invasive species, it’s such a pest in Great Britain that as recently as five years ago you couldn’t get a mortgage if there was Japanese knotweed on the property. (That has since changed.)

Of course I was happy to see these two “Japanese” species together.  The beetles felt so at home on the knotweed that they were mating on it.

My hope is that the female beetles will drop to the ground below the knotweed and lay their eggs.  When the eggs hatch the larvae will burrow underground and eat the roots of nearby plants.

Good.  Eat the knotweed roots.  Eat the leaves.  Go on, Japanese beetles.  Keep eating!

(photos by Kate St. John)