December 2019 Master Gardener Column

By Jan Phipps

In the past, horticulture specialists recommended clearing your annual and perennial gardens of all debris in late fall after the first freeze when everything above ground was dead. No longer. Now we better understand the importance of leaving that debris for overwintering beneficial insects. Of course, problem insects also utilize the same protection, but maintaining a balance between the good and bad is a realistic approach.

Last year I read an article by Kelly Allsup, Extension Educator, who listed some beneficial insects and how they spend the winter in our gardens.

Ladybugs, those efficient aphid killers, spend the winter as adults under branches, in logs, and nestled in the thick protective cover of ornamental grasses. A single ladybug can eat as many as 5000 aphids during their life, so they are definitely one of the good guys.

Green lacewings are most noticeable as adults; however, they do their best work as larvae (a.k.a. aphid lions) eating up to 40-60 aphids per day. Grabbing an aphid, they inject paralyzing venom, suck out the juices, then throw the carcass on the ground. They spend the winter as pupae attached to stems and leaves.

I know some people have an aversion to spiders, but they play an important role in our garden ecosystem. Many spiders overwinter as egg cases, but jumping spiders, wolf spiders, and some crab spiders survive the winter as adults or juveniles in rotting logs, leaf debris, and bricks.

Leafcutter bees and mason bees along with other native bees overwinter as young larvae in the pith of stems or holes in stumps and logs. Carpenter bees spend the winter as an adult; the queen finding a crevice somewhere in the garden. We all know the importance of bees to our food chain.

Moths and butterflies overwinter as caterpillars, pupae, or adults depending on the species. It could be on the soil surface, secluded in leaf litter, hidden in dead plants, or any other protective space in your garden.

If your aim is to grow a healthy, beautiful, abundant garden, you will need the help of beneficial insects. Removing their winter quarters could mean removing them; something we all want to avoid.

The Illinois Extension Master Gardeners of Edgar County wish you a happy holiday and productive new gardening year. We can be reached at 217-465-8585.