Monarch & The Milk Weed … to plant, or not to plant?

Monarch Deformities — A Growing Concern

There is a pesty parasite that is killing the monarchs in all stages of their life cycle. The parasite is called OE for short. It appears that with a warming climate, the monarchs don’t migrate and the non-native milkweed doesn’t die back in the winter, especially in Florida. This seems to perpetuate the life cycle of OE and negatively impact the monarchs. 

Recent field observations have shown monarchs emerging with wing deformities, weakness, or other irregularities. These issues are often linked to the protozoan parasite Ophryocystis elektroscirrha (OE), which can build up on milkweed leaves when tropical or non-native species are grown year-round. Pesticide drift, herbicide use, and loss of native habitat may also stress monarch populations, increasing the likelihood of deformity.

Photo: Monarch butterfly showing wing deformities, highlighting risks of improper milkweed planting.

By using native milkweed species that naturally die back in the winter, gardeners can help break the parasite cycle and reduce deformity risks. Cutting back tropical milkweed in the fall, avoiding pesticides, and planting diverse nectar sources alongside milkweed all help monarchs stay healthier.

Here are the recommendations from FNPS based on the best available science as to what to do. Mainly, rip out all of the non-native (Tropical) Milkweed, and only propagate native varietals. 

Florida Native Plant Society (FNPS): https://fnpsblog.blhttps://fnpsblog.blogspot.com/2024/05/florida-native-plant-society-position.htmlogspot.com/2024/05/florida-native-plant-society-position.html

First published 19 August 2024 … on SustainZine.com (Now integrated into Perpetulinnovation.org/pi-sustain/ )
Updates Sept 13, 2025.