Hello! Thank you so much for offering this awesome service!!! I am trying to...
Hello! Thank you so much for offering this awesome service!!! I am trying to be a conscientious wildlife gardener (planting native species, not using chemicals, etc.) in my flower garden. I'm in IA (Zone 5) and would normally have raked leaves in my flower bed, cut down dried perennial stems from last fall (the usual spring clean up), but... on a wildlife blog, I read that leaf litter and the dried perennials can house insect, moth, butterfly larvae (etc.) and cleaning it up could destroy critters about to hatch. The other side of the argument is... leaving the leaf litter could spread/introduce disease to my perennials, which would surely not be desired. Plus, the neighbors probably think I'm a slob, but if some butterflies are yet to hatch, I don't care what they think. So.... what do you know about this... In my Zone 5 garden, when do you think I can safely clean up for spring, yet not compromise any beneficial insect life? Thanks so much!!! Wendy :)
The following response was provided by Donald Lewis (ISU extension entomologist).
Mulch, brush piles and debris provide cover for many animals including some insects. However, the number of butterflies in regular perennial garden debris is going to be very small and raking in the fall or spring will not make much difference. There are some notable exceptions, but not many. The black swallowtail caterpillar that feeds on dill during the summer attaches its chrysalis to the dried stems in the fall. That is one butterfly that is favored by leaving the plant debris in the fall. For others there is little to no benefit in part because of where they are spending the winter. See the article in the 3/17/2010 Hort Newsletter for more information.