The Crafty Cultivator

I don’t think I have written about my Delphinium worm battle much, apart from an old post in 2017. This was from before I knew a much easier way to win the battle against these pests. I had this post almost ready to go in 2022, but then I was growing a human and real life took priority over posting things on the internet. I was reminded I had this post in my back pocket as I was writing about moving my delphinium (this very plant actually) last week.

Rather than meticulously picking off the caterpillars before they completely damage the leaves of my delphiniums, (like I did in 2017) as soon as I see leaves starting to curl up and fill up with tiny caterpillars and their large amount of poop (if you want to sound more professional or mature, you can call this “frass”), you chop the entire plant back.

Unless your plant is super young, there will be enough energy in the roots for it to grow new leaves… and flowers. By completely removing the leaves/food source for the caterpillars, they have no food source and should die out before the plant sends up it’s new growth.

It seems counter intuitive to completely cut back your plant’s beautiful new growth, but this has been the best way to still enjoy my delphiniums. Plus, no need to meticulously inspect your plants and squish the bugs as soon as you see them. AND your plant doesn’t have to struggle trying to survive this onslaught.

When I get my delphiniums cleaned up in the fall, I have less of a problem the following Spring, as there is no where for the bugs to overwinter. But last fall was a rough time and the very last thing on my mind was delphinium worms.

So while yes, it is difficult to fully cut back brand new spring growth that we have waited ALL winter to see, this really is the best way I have found to win the battle against the delphinium worms, AND still enjoy my delphiniums. They are one of my favorite flowers. I won’t ever completely be free of the delphinium worms because my yard is not a closed system. Other people have delphiniums (and other closely related plants) and likely delphinium worms, so the little buggers will always have a close place to overwinter, even if it is not in MY garden.

The photo above is a short flower spike, but it was the same plant in the same year as the above cut-back. I still get flowers, even if they aren’t the same height as they would be if they didn’t get cut back. However, if I just left the worms to do as they please, I don’t get flowers at all, and my plant struggles to even live.