I’m so glad I decided to grow hollyhocks again after a long pause. Some of my plants grew almost 10 feet tall with big, beautiful, bumblebee-approved flowers!
In past years my hollyhocks had to endure the attacks from Japanese beetles that like to feed on the flowers and leaves. Thankfully, this summer they were a minor nuisance.
But in August I didn’t spend as much time in the garden, and that’s when another tiny monster attacked and completely skeletonized the plants!
This thorough munch-a-thon is the work of hollyhock sawfly larva. As devastating as this damage is I had to laugh when I read a description from a retired Extension Horticulturist from the University of Arkansas Division of Agriculture:
“The translucent green worms are up to ½-inch long and kind of club shaped with a black spot on their head and on spines located on each body segment. They seem to get lonely for it is not uncommon to see them grazing side by side like a heard of cattle in a lush pasture.“
You can see the spot on his head, and they are definitely grazing like cattle on what’s left of my hollyhocks!
The horticulturist gave advice for control that is too late for me to take advantage of, but this is good information for next year!
“Control is not especially difficult but should be initiated as soon as the first holes are seen on the lower leaves. Sevin or BT should prove effective. I have not controlled the hollyhock sawfly on the plants in the campus garden and have seen no sign of natural enemies attacking the pest. I did observe the adult sawfly attack the caterpillar of a competing species, thus assuring more room for its own brood.”