Like a growing number of other backyard wildlife enthusiasts I am incorporating native plants into my home landscape. To date, I have been pleased with native plants I have introduced that produce seeds, fruits, berries and/or nectar for my wildlife neighbors. I wish I could say the same for two caterpillar host plants—passionflower and spicebush. My problem with them is two of the butterflies that lay their eggs on them do so long before the plants can become established.
This problem first cropped up several years ago when I tried to grow passionflower in my yard. After vainly trying to grow the plants from seeds, I planted young plants. Much to my delight the plants did well and soon slender passionflower vines inched their way up a nearby fence.
One day when I went out to look at my rapidly growing vines I spotted a number of spike-covered orange and black gulf fritillary caterpillars munching on the vines’ tender leaves. At first I was thrilled that gulf fritillaries were using my plants as hosts for their caterpillars.
My delight soon changed to concern when it became the insatiable caterpillars quickly devoured every single leaf on the vines. They then proceeded to eat the vines down to the ground.
Although my crop of passionflower leaves was exhausted for that growing season, I was hoping the plants would come back the following year.
The next spring I kept looking for the passionflower vines to emerge from the ground. When this did not happen I realized the caterpillars had destroyed the plants the previous year.
This problem resurfaced when I transplanted a healthy four-foot tall spicebush in my backyard last year. Aided by frequent watering, the small shrub grew well. Much to my surprise, in 2017 I did not see a single spicebush swallowtail caterpillar on the plant.
This spring the tree sprouted a meager crop of fresh green leaves. Eventually, I notice a number of folded-over leaf shelters on the leaves. This was a sure sign tiny spicebush swallowtail caterpillars were hiding beneath their green leaf shelters. In a matter of days, these voracious caterpillars ate every single leaf on my spicebush. I was hoping I was not facing a replay of my experience with passionflowers.
My fear that caterpillars had once again destroyed a host plant in my yard was alleviated when I noticed small green buds had appeared at the shrub’s woody base. Perhaps I still had a chance to save the plant.
I decided the best thing I could do to save the shrub was to somehow prevent female spicebush swallowtails from laying their eggs on the few newly-sprouted leaves. With that in mind, I have wrapped a small piece of bird netting around the base of the plant in hopes spicebush swallowtails will not be able to extend the tips of her abdomens through the netting far enough to lay their eggs on the new leaves; only time will tell whether or not my efforts will prove successful.
In the meantime I am checking the shrub daily to see if my efforts prove to be successful. I also want to make sure a snake doesn’t become entangled in the netting.
If it works, I might just try to plant passionflower again. In the meantime, I just wish butterflies would be a little more patient.
If you have discovered a solution to this dilemma, please let me know.