Every summer in Florida, the warnings begin again. Gardeners are told to rip out tropical milkweed. Social media fills with claims that tropical milkweed is harming monarch butterflies. Native plant advocates amplify the message. And before long, tropical milkweed has become the villain in one of the most emotionally charged debates in modern gardening and pollinator conservation.

But the reality surrounding monarch butterflies and OE is far more complicated than the simplified narrative often presented online.

The Part of the Story Rarely Discussed

Most monarch butterflies seen in Northeast Florida likely belong to populations tied to South Florida overwintering groups rather than the massive Midwest migratory population that famously travels to Mexico. And here is the key detail often left out of the conversation:

Scientists estimate that roughly 70–95% of South Florida’s resident monarch population is already infected with OE (Ophryocystis elektroscirrha), a naturally occurring protozoan parasite that has existed alongside monarchs for a very long time.

This is not a newly discovered disease caused by tropical milkweed. OE predates tropical milkweed’s popularity in ornamental landscapes by centuries, likely millennia. It is endemic throughout monarch populations and migratory routes, including among butterflies that successfully overwinter in Mexico.

The difference is prevalence.

Researchers often find much lower OE infection rates among monarchs completing the migration to Mexico because migration itself acts as a natural filter. Heavily infected butterflies are less likely to survive the journey. Meanwhile, South Florida’s warm climate allows monarchs to breed year-round, creating a resident population where OE continuously circulates generation after generation.

OE Exists on Native Milkweed Too

One of the most overlooked realities in this debate is that OE does not require tropical milkweed to persist in Florida.

OE spores survive on monarch host plants broadly, including native Florida milkweed species that remain active through South Florida’s mild winters. Florida’s climate itself naturally supports more continuous breeding than northern states.

That means even in a world without tropical milkweed, OE would still exist within Florida monarch populations.

Scientists associate tropical milkweed (Asclepias curassavica) with potentially higher OE transmission rates because it remains lush year-round and may encourage denser, non-migratory monarch populations. That argument is reasonable as far as transmission ecology goes.

But that is very different from claiming tropical milkweed created OE.

A more accurate comparison would be efforts to reduce malaria transmission by limiting mosquito breeding habitat. Reducing transmission opportunities is not the same thing as eliminating the disease itself.

Enter the Native Plant Movement

Native plant advocates understandably favor native milkweed species over tropical milkweed. In many cases, their arguments for ecological restoration, biodiversity, and native landscapes are valid and beneficial.

But through effective messaging and strong public relations, some corners of the native plant movement have helped turn tropical milkweed into a symbolic enemy of monarch conservation.

The result is often an oversimplified narrative:

• native milkweed equals good,

• tropical milkweed equals bad.

Reality is far murkier.

Monarchs in Mexico also utilize tropical milkweed species and closely related milkweeds throughout their native range. OE itself is present throughout monarch migratory populations, including in Mexico. And Florida’s unique subtropical ecology naturally supports resident monarch behavior regardless of tropical milkweed’s presence.

Are We Focusing on the Wrong Problem?

The uncomfortable question rarely asked is this:

If South Florida’s resident monarch population is already approaching near-universal infection rates, should more scientific attention be directed toward understanding and potentially treating OE itself rather than primarily targeting one ornamental host plant?

Current conservation messaging often places enormous emphasis on limiting transmission while accepting the parasite itself as unavoidable.

But from another perspective, monarch butterflies do not simply need less tropical milkweed. They need breakthroughs in understanding OE, interrupting severe infections, and improving long-term monarch health.

That may prove difficult. OE is deeply embedded in monarch ecology and likely impossible to eradicate entirely from wild populations. But focusing the public conversation almost entirely around tropical milkweed risks reducing a complex continental ecological issue into a simplistic gardening controversy.

The Bigger Picture

Monarch declines are influenced by many factors:

• habitat loss,

• agricultural herbicide use,

• climate variability,

• drought,

• loss of native prairie ecosystems,

• pesticide exposure,

• and changing migration behavior.

Against that backdrop, the intense vilification of one ornamental milkweed species can sometimes feel disproportionate to its actual role within a much larger ecological system.

Tropical milkweed may influence transmission dynamics. That is fair scientific discussion.

But tropical milkweed is not the origin of OE. It is not the sole reason monarchs struggle. And it is certainly not the only factor shaping monarch populations in Florida.

The story is far more complicated than the internet often wants it to be.