Are Pests Overwintering in Your Garden?

Finally drained and rolled up the garden hose, swept cobwebs from corners of the porch, and washed windows in preparation for winter weather?

Gives us a warm ‘look what I’ve done’ feeling every time we finish those seasonal tasks. But wait! Take another look at those flower beds and vegetable gardens – they need cleaning out, too. One of the least toxic and most helpful things we can add to our Fall “to do” list is the simple act of cleaning up.

Case in point: Canna leaf rollers. Don’t have canna lilies in your garden or yard? That’s OK, but I’ll bet you have something that overwinters in debris that accumulates, is left where it falls, and provides great harborage for pests that appear every year during spring and summer.

controlling pests overwintering in garden

Canna leaf rollers are one of the pests that can overwinter in your garden.
Photo: Home Design

Back to Canna leaf rollers: these voracious little caterpillars, the larval form of the large brown skipper butterfly, start the process around April in our area. Feeding in groups, they roll leaves together and feed in a snug, protected environment. However, since they overwinter as larvae in rolled canna leaves, cutting or pruning off the above-ground stalks of canna in late fall and winter will remove a sizeable segment of the population without any other form of pest control.

Along with cabbage worms, cucumber beetles, and tomato hornworms, which also ride out winter in leftover debris, these pests are left protected and waiting to reappear next spring as temperatures warm.

Will an “extra cold” winter kill them off? Maybe a few of the weaker ones, but like most insects adapted to our climate, the majority will survive to start the cycle again in spring. So why not give your cannas and other garden plants a head start by getting rid of the generation smugly snuggled in leftover debris? A gardening friend works off her Thanksgiving feast by cleaning out her canna beds the following day!

So, remove that withered, blackened vegetation left from summer harvest, and remains of those ragged canna leaves. It will help control overwintering garden pests. This could become a new post -Thanksgiving tradition!

By Sallie Lee, Urban Regional Extension Agent, Alabama Cooperative Extension System.  Contact Sallie at

The Alabama Cooperative Extension System (ACES) operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities. ACES is committed to affirmative action, equal opportunity and the diversity of its workforce.  Educational programs of ACES serve all people regardless of race, color, age, sex, religion, disability, sexual orientation, or national origin.

Alabama Extension

The Alabama Cooperative Extension System operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities and answers home-gardeners' questions each week on Birmingham Gardening Today.

4 thoughts on “Are Pests Overwintering in Your Garden?

  1. Found significant infestation of Brown Skipper Butterfly caterpillars in our “Hardy Water Canna (Thalia Dealbata)”. Destroyed many leaves overnight and were in the process of folding themselves in. Each caterpillar was about 2″ long and we pulled eleven off the single plant we have in our small pond.
    Located in Fairhope Al.
    Are these toxic to fish if they fall into the water or to birds? Noting the article on this subject is the most likely source of the caterpillars from garden debris? We have many trees and a large amount of leaf waste in the garden.

    • Wow, So glad I found this site. This is the 1st year that I have planted Thalia dealbata and I am in love with the foliage.No flowers yet however. But when I went outside this morning and took my morning walk around the plants, My Thalia looked like it had been beaten up!I had a hissy fit and then I found the culprits. I have the Brown Skippers too.I love my butterflies,but this isn’t tolerable.I guess I am going to have to get used to it.

      • Might try dusting with Bacillus thuringiensis commonly called BT if you want to control the catapillers. It is organic and will not injure the plant just get bugs.

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