Like so many Florida residents, Taylor Jones embraced year-round gardening when he moved from the Northeast to a prominent corner lot in Mount Dora a little over three years ago.
And like more gardeners throughout the world, Jones wanted to help struggling populations of bees and butterflies by planting flowers they use for food and breeding.
So he planted tropical milkweed. Plenty of monarch butterflies showed up. But then Jones learned a disturbing fact. Planting tropical milkweed in Florida, where it’s not native, might actually be harming the local population of monarchs. That’s because, according to researchers at University of Florida and University of Georgia, monarchs that would normally fly to winter breeding grounds in Mexico end up staying in Florida.
That is really cool if you just want to see butterflies in your yard all year. But entomologists say Florida’s population of butterflies – particularly in Northern and Central Florida – is vulnerable to cold snaps if they spend the winter here.
Even worse, research shows they are also more likely to carry a disease-causing parasite called OE (Ophryocystis elektroscirrha) that causes birth defects in emerging butterflies, like crumpled wings and dwarfism.
“You do feel awful when you see a crumpled butterfly that you know is sick,” says Jones, who is a syndicated editorial cartoonist. “You have to be careful about how you try to address the natural world. Things get complicated.”
Jones now plans to follow advice that has been making the rounds in bug research for a few years: Cut the tropical milkweed down to the ground sometime in October so monarchs don’t settle in for the winter.
It’s part of a growing awareness that simply planting the most popular milkweed variety – tropical or Mexican milkweed – may not be the best strategy to help the monarch. While they love it, too much tropical milkweed in the U.S. could represent loving the monarch to death.
MIGRATION MYSTERIES
Science is just starting to understand nuances of the monarch’s breeding and migration habits, led by researchers like University of Georgia ecologist and associate dean Sonia Altizer. Altizer is credited with first noting that the monarch’s famous 3,000-mile journey to winter locations in Central Mexico appears to help the pretty bugs outrun the OE sickness.
Basically, infected butterflies can’t handle the journey. So the monarchs that make it that far are assured of reproducing with a healthy mate. You might compare it to humans who would only date people who recently did an Ironman competition.
But planting a lot of tropical milkweed in Florida is like having too many donut shops along the road to the Ironman, tempting competitors to cancel their race and pig out, thus missing their potential athletic mating partner.
“We think that migration weeds out the most heavily infected monarchs, removing them from the populations,” Altizer told National Geographic in a 2017 article about her research. She has found that adult butterflies infected with the protozoan OE parasite can’t fly as well in lab tests and travel shorter distances in the wild. Research is ongoing.
The prevalence of monarchs in Central Mexico breeding sites for 2017-2018 showed a 14.8 percent decline compared with the previous year, according to surveys by the World Wildlife Federation in Mexico. That’s part of a trend that’s seen a 90 percent drop over 20 years. Hurricanes, including Harvey and Irma, likely disrupted southern migration last year, the WWF said.
PUBLIC AWARENESS
In April, the Nature Conservancy, along with Full Sail University and Ink Dwell Studio, launched the Monarch Initiative in Central Florida to spotlight the fact that and other butterflies and pollinators such as bees need favorable habitat to thrive.
The Conservancy’s main goal is to promote the preservation of natural spaces, and the website for the Monarch Initiative includes a call to plant milkweed. But the Initiative hadn’t directly addressed the issue of native milkweed being preferable to the tropical variety until very recently. As more research is becoming available, they’re updating their information and programs.
They’ve also handed out native milkweed seeds at public events, says Fran Perchick, communication and media manager for the Conservancy in Florida. At themonarch initiative.org, you can find a list of native milkweed varieties, and there are plenty – Florida has 21 species of native or swamp milkweed.
Jaret Daniels, associate professor of lepidoptera research and insect conservation at University of Florida, says casual gardeners are confused.
“We hear from the public that they don’t know where to find native milkweed, and we hear from nurseries that they don’t believe there’s a market for it. So it’s a chicken-and-egg thing,” Daniels says.
He’s glad that more people are interested in planting for pollinators. He still tells people they can grow tropical milkweed, but he says they should cut it back in the fall.
“If the monarchs are here all winter, they are continuously breeding here in Florida and the parasite can build up in small populations and reach outbreak levels, versus remaining at lower levels,” Daniels says.
Some scientists believe the monarch has had a year-round population in South Florida for years, but with a higher incidence of OE. The prevalence of tropical milkweed has grown in recent years with larger plant distribution networks at big box retailers.
The City of Orlando’s Leu Gardens has been telling gardeners how to attract bees and butterflies for years, says director Robert Bowden.
“The whole term ‘pollinator garden’ is fairly new, but we’ve had butterfly gardens and plantings that attract pollinators for years. Low numbers of honeybees have drawn more attention over the years, but bees appear to be doing fairly well again,” Bowden says.
He’s waiting for more published science about tropical milkweed in Florida before he rips out the plant at Leu, but for now, he and the staff there are cutting it back in fall.
BUTTERFLY MAN
Either way, the popularity of butterflies seems to have exploded recently, says Lorenzo Zayas, the so-called “butterfly man” of the Winter Park Farmers Market.
Zayas is a true gem of local culture. He has held court every Saturday morning at the market for the last 30 years selling butterflies, chrysalises and plants that he has raised on his three-quarter-acre property in Apopka. He uses no pesticides.
Business has been so good lately it’s now his full-time job.
“When I started many years ago, I was a total mystery,” he says with a laugh.
Researching the local species wasn’t so easy decades ago, he recalls. “There was no book telling you then what plant each butterfly eats. I took photos of them and figured it out.” He remembers loving butterflies as a child, and says he studied as an entomologist in the Caribbean many years ago, focusing on termites and ants.
Zayas says pesticides and human destruction of habitat are responsible for the monarch’s decline. He says pesticide is another common mistake people make when they plant pollinator gardens. Such gardens require that you use only limited, natural means to control pests – like small applications of soapy water for aphids, or knocking down wasp nests physically, rather than using wasp spray.
“There’s a spray or poison for everything now. You can’t do that. You can’t just spray for mosquitoes … other things are affected,” he says.
He brings butterflies to schools sometimes and lets children touch them, gently. He encourages everyone to read Rachel Carson’s 1962 classic book Silent Spring, which documented the harmful impact of widespread pesticide use.
“It’s just incredible how clearly and how eloquently she put it,” Zayas says. “Don’t poison your environment. Otherwise you’re going to be killing bees and killing birds. Now, everyone knows that if you kill them, you don’t have any honey, or food.”
GOING NATIVE
There’s another local initiative aimed specifically at planting more native milkweed, led by the Florida Association of Native Nurseries (FANN) and the international Xerces Society.
Native milkweed gives monarchs plenty to eat and lay eggs on in the spring. But native milkweed – usually pink or orange flowers, while the tropical variety has a bi-colored flower in red and yellow or solid yellow – dies back almost totally by mid-summer.
Native milkweed in the U.S., also known as swamp milkweed, used to thrive in wet areas around corn and soybean crops – vast territory in the nation’s heartland. But that kind of milkweed, like any other weed, was drastically reduced when Monsanto’s “Roundup Ready” crops were introduced. Roundup herbicide can be sprayed without killing the crop, so it’s easier to get rid of weeds – including milkweed.
In Groveland, Marc Godts runs one of those native-plants-only operations, Green Isle Gardens nursery. He does believe people should start weaning themselves off tropical milkweed. He’s a volunteer with FANN and the Florida Milkweed Project, which works to build up seed supplies for native milkweed.
“More and more folks are wanting to do wildlife habitat/pollinator gardens, and that’s good, but some people have a lot to learn about how to go about it,” Godts says.
He says people come into his nursery frantic because monarch caterpillars have eaten all the milkweed.
“Sometimes we don’t have any more, and I tell them, I’m sorry but that’s part of the life cycle. That’s part of the bug world,” he says.
MORE THAN MONARCHS
Pollinator gardens are about more than the monarch, of course. Bees, probably the best pollinators, can be attracted by lots of plants, notably any variety of basil herb, but especially the African blue basil. The luffa gourd vine (yes, that’s where loofah sponges come from) has flowers that bumblebees can’t resist. To attract the state butterfly, the zebra longwing, plant passion flower vines. Black swallowtails love parsley and dill. The only known host plant for the zebra swallowtail is the pawpaw tree. Pentas flowers, which are common in Florida landscaping, are great nectar plants. But be careful about where you get them.
Daniels, the UCF professor, says research has been done to determine what is on the plants sold by the big-box retailers.
“It’s all across the board. Sometimes it can be safe, but you can go back and try another and it will have chemicals and be unsafe for a period of time,” Daniels says. “Only the supplier has that information, and they probably don’t share that with the retailer.
Having a variety of plants will also help the garden look good throughout the year.
“I like native plants, but many of them don’t bloom very long and they look pretty lousy when they stop blooming,” says Jones, the Mount Dora gardener. “I live on a prominent corner and I want it to look good. So I’ve learned to mix it up.”
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This article appears in Oct 17-23, 2018.