In Defense of Weeds

By Joan Butler

One summer day a few years ago, I noticed a very large spotted white moth resting on a leaf in my crabapple tree. I was amazed by its size and distinct markings, unlike anything I had ever seen before. Eventually, I tracked down its name – it was a Giant Leopard Moth. And I learned that in its caterpillar stage, it dines on broad leaf plants such as plantains, dandelions and violets. These are usually considered weedy plants, and are aggressively eradicated from lawns and gardens. But here was a creature that relied on them as a food source!

Giant Leopard Moth

This past summer, I had two new types of butterfly visit my garden. Once again, I had to do some research to figure out what they were, and what their larvae fed upon.

Red Admiral

The first were Red Admirals. They busily worked on the pink coneflowers in my backyard – what a joy! When I read what their caterpillars ate, though, I was puzzled: nettles and hops, which were not plants I had growing in my gardens, nor did my nearby neighbors.

clearweed

I did, however, have a weed that had gone crazy in one corner of the yard. I don’t use herbicides, and I was too busy to contend with it manually. I finally identified it as Clearweed, and learned that this eastern US native is a non-stinging member of the nettle family! The hand of Mother Nature seemed clear in the relationship between the Clearweed growing out of control and the appearance of Red Admirals in my gardens.

Common Buckeye

The second new visitor arrived just as my Sedum ‘Matrona’ was entering its prime, and it busily worked the flowers alongside scores of honeybees and native bees. I came to learn that this newcomer was a Common Buckeye, but there was nothing common about it as far as I was concerned - I was thrilled. I’m sure you have already guessed that, once again, one of the preferred foods of the larval stage is a weed: plantain.

plantain

Every summer, I await the reappearance of Fritillary butterflies. They seem especially fond of the nectar of Verbena bonariensis and coneflower, but they also require the presence of violets. The female lays eggsin late summer on or near violets. The eggs hatch in fall. The young caterpillars overwinter until spring, when they begin dining on violet leaves. Without violets, which are the only plant the caterpillars consume, there would be no Fritillary butterflies.

Fritillary butterfly

common violet

Over the last decade, there has been a surging interest in including native plants in our gardens, as we have come to recognize their vital role in our ecosystem. A functioning food web is created by using plants that evolved with our native animals - and insects. And we probably should allow some weeds in the mix.