Monarch butterflies (Danaus plexippus) are among the most recognized and beloved pollinators in North America. Their remarkable long-distance migrations and dependence on milkweed plants for reproduction have captured the attention of scientists, gardeners, and conservationists alike.

But monarchs are in trouble. Over the past few decades, monarch populations have declined dramatically—due to habitat loss, climate change, disease, and well-intentioned but misguided gardening practices.

To truly help monarchs, especially in Florida, it’s critical that we understand the challenges they face and take informed action—starting with native milkweed.

Milkweeds (Asclepias spp.) are the only host plants that monarch caterpillars can eat. Female monarchs lay their eggs exclusively on milkweed, and once hatched, the larvae feed on the leaves. This close relationship makes the availability and quality of milkweed essential to monarch survival.

Florida is home to approximately 20 species of native milkweed. These plants have evolved with local wildlife, bloom at appropriate times, and go dormant during winter—naturally supporting the monarch’s migratory life cycle.

1. Disrupted Migration

Tropical milkweed can cause monarchs to linger in Florida year-round instead of migrating, especially in southern parts of the state. This sedentary behavior may interfere with their internal cues for reproduction and overwintering.

2. Increased Disease Risk

Tropical milkweed also promotes the spread of a debilitating parasite called (OE) (Ophryocystis elektroscirrha). OE spores build up on plants over time. Because tropical milkweed does not die back seasonally like native milkweeds do, OE accumulates—infecting successive generations of monarchs. Infected butterflies can be weakened, deformed, or unable to fly.

3. Genetic Isolation and Population Bottlenecks

When monarchs overwinter in non-traditional areas like Florida due to the presence of tropical milkweed, they may become reproductively isolated from migratory populations, leading to reduced genetic diversity and resilience.

4. Climate Change and Habitat Loss

In addition to problems caused by tropical milkweed and disease, monarchs are increasingly affected by climate change and habitat destruction:

• Rising temperatures can alter migration timing, reproductive behavior, and survival rates.
• Droughts and extreme weather events can destroy milkweed habitat and reduce nectar availability.
• Urbanization and agricultural intensification have led to widespread loss of native plants, including milkweed, across the monarch's breeding and migratory corridors.

What You Can Do: Plant Native, Be Part of the Solution

Plant Native Milkweed Species

• Choose regionally appropriate species like Swamp milkweed (Asclepias incarnata), Butterflyweed (Asclepias tuberosa), Aquatic Milkweed (Asclepias perennis), and Pinewoods Milkweed (Asclepias humistrata).
• Do not plant Tropical milkweed (Asclepias curassavica). If already planted, remove it.

Create a Monarch-Friendly Garden

• Include a variety of nectar plants to support adult monarchs and other pollinators.
• Do not use pesticides and herbicides.
• Let your garden reflect natural rhythms—seasonal dieback and diversity are part of a healthy ecosystem.

Sanitize and Monitor for Disease

• If you suspect OE infection, contact a local butterfly expert or extension agent.
• Encourage community awareness about OE and the importance of native plants.
  

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