Butterfly Lady

Milkweed seeds are small time‑travelers. Each one carries a built‑in memory of winter, a biological expectation that cold, moisture, and patience will signal when it’s safe to emerge. For gardeners, educators, and habitat‑builders, understanding this process is the key to turning a handful of seeds into a thriving patch of monarch‑supporting plants.

Cold stratification sounds technical, but it’s simply the act of mimicking winter. I used to be intimidated whenever I saw the term “cold stratification” on seed packets. Since then, I have learned it is a simple technique, and there’s more than one way to do it. Whether you garden in a snowy climate, a warm region like South Florida or Texas, or somewhere in between, you can choose the method that fits your space, your schedule, and your style.

What Cold Stratification Actually Does

Cold stratification, also known as seed stratification, is the process of exposing seeds to cold and moist conditions to encourage germination. In nature, the stratification process takes place when fallen seeds overwinter underground or beneath a layer of snow. But you can accomplish the process yourself by replicating Mother Nature.

Four Reliable Ways to Cold‑Stratify Milkweed Seeds

1. Direct Outdoor Fall/Winter Sowing

The perfect time to sow native milkweed as well as other native perennials outdoors is right when Mother Nature does it, in the fall! Exposure to cold temperatures and moist conditions during winter will stimulate germination.

How to do it:

1. Prepare a weed‑free patch of soil.
2. Scatter seeds on the surface.
3. Press them in gently (milkweed needs light to germinate).
4. Let winter weather do the rest.

2. Winter Sowing in Containers

This method is a favorite for many gardeners and perfect for beginners. Winter sowing uses vented containers (milk jugs, takeout boxes, rotisserie chicken domes, Ziplock bags) as mini‑greenhouses. You sow the seeds, set the containers outside, and let nature handle the cold, moisture, and temperature swings.

How to do it

1. Choose a translucent container (milk jugs, clamshells, etc.). If using a milk jug, discard the cap.
2. Add drainage holes on the bottom of the container using a drill or hot glue gun. Add ventilation holes on the top of the lid if using plastic container.
3. Fill bottom with 3-4 inches of moistened potting soil ( I recommend Promix Seed Starting Mix).
4. Sow seeds on the surface and press them in lightly.
5. Tape the container closed.
6. Label clearly with a waterproof marker.
7. Place outside on a flat surface exposed to rain, snow, and sun.
8. Water as needed to keep soil moist.
9. Remove lid when seedlings emerge.
10. Transplant the seedlings when seedlings have become established and have developed true leaves.

    

Why gardeners love it

• No fridge space needed
• Naturally timed germination
• Protects seeds from birds and wind
• Great for large batches

3. Refrigerator Cold‑Moist Stratification

A controlled indoor method that works in any climate. This technique mimics winter inside your refrigerator.

How to do it

1. Moisten a paper towel, sand, perlite, or vermiculite until damp but not dripping.
2. Mix in the seeds or fold them inside the towel.
3. Seal in a labeled bag or container.
4. Refrigerate for 30–60 days.
5. Plant once the stratification period is complete.

Why it’s useful

• Predictable and consistent
• Ideal for warm‑climate gardeners
• Great for small seed batches or precise timing
  
  4. Cold‑Moist Stratification in Pots, Also Known as “Seed Sitting”

I recently discover a very easy way to grow native milkweed and wildflower seeds called Seed Sitters which was created by the David Suzuki Foundation. Seed Sitters is an inexpensive and simple way to grow native milkweeds and other native plants through winter sowing on a balcony on in a backyard.

How to do it

1. Fill pots with potting mix.
2. Sow seeds on the surface and press lightly.
3. Leave pots outdoors all winter in a protected spot.
4. Cover with mesh if critters are an issue.

Why it works

• More controlled than direct sowing
• No indoor space required
• Easy to move seedlings once they sprout

Cold stratification is more than a gardening technique, it’s a way of participating in the seasonal rhythms that monarchs depend on. Each seed you prepare is a promise of nectar, shelter, and migration support. Whether you’re winter sowing on a patio, stratifying seeds in your fridge, or scattering them across a wild patch of land, you’re helping rebuild the living corridors that butterflies, bees, and countless other species rely on.

And that’s a beautiful thing to grow.

Winter sowing in zip‑lock bags is simple, low‑cost, and surprisingly effective way to winter sow native milkweed and perennial seeds. It is also a low mess alternative to milk jugs. Ziplock bags act like mini cold frames, letting moisture, light, and fluctuating winter temperatures stratify seeds naturally. They’re lighter and easier to store than jugs, and they warm quickly on sunny days.

Here’s a clear, gardener‑friendly walkthrough to help you get started.

What You Need

• Quart or gallon freezer‑grade ziplock bags (sturdier = better)
• Seed‑starting mix (Not garden soil. I like using Organic Promix because it contains MYCOACTIVE to stimulate vigorous growth and greater resistance.
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• Spray bottle with water.
• Permanent marker for labeling.  I use Garden Markers because they are waterproof and will not fade.
• Seeds suited to winter sowing (Native milkweeds, perennials, hardy annuals)
  

  Click here to Find Native milkweed seeds for your area.

Click here to find native perennial seeds for your area.

Prepare the Bag

• Cut two small drainage slits in the bottom corners.
• Add 4-5 inches of moist seed‑starting mix.
• The mix should feel like a wrung‑out sponge.

Sow the Seeds

• Sprinkle seeds on the surface.
• Press gently so they make contact with the soil.
• Cover lightly only if the species requires it (many natives need light to germinate).

Seal for Ventilation

• Zip the bag almost closed, leaving a ½‑inch gap for airflow.
• This prevents mold while still holding humidity.

“I started winter sowing today with 8 types of milkweed . This was just before we hung the bags outside. I have many other bags to prep and hang outside. This was such a successful method for me last year! ” Jennifer Zolinski Gezequel  

Place Outdoors

• Set bags in a bright, open area that gets rain.

Jennifer Zolinski Gezequel hangs ziplock bags using stakes laying across raised beds.

Let Nature Work

• The freeze and thaw cycles stratify the seeds.
• Condensation inside the bag is normal and acts like a tiny greenhouse.

Monitor in Early Spring

• When seedlings appear, gradually open the bag wider over a week to acclimate them.
• Once they’re sturdy, transplant into pots or directly into the garden after the last frost in your area.

Male butterflies frequently seek out plants that are rich in alkaloids, not simply for nourishment but for pharmacology—the deliberate ingestion of plant chemicals necessary for producing sex pheromones. These pheromones, which are derived from the alkaloids consumed, are stored in specialized scent organs and later released during mating rituals to attract female butterflies.

Chemical Attraction and Courtship in Queen Butterflies

A notable example of this behavior is seen in the Queen butterfly (Danaus gilippus). Male Queen butterflies are particularly attracted to Gregg’s mistflower (Conoclinium greggii) due to a unique chemical interaction that significantly influences their mating behavior. Gregg’s mistflower produces a high concentration of alkaloids, especially pyrrolizidine alkaloids, which the male butterflies actively seek.

Male Danaus gilippus butterflies—commonly known as Queen butterflies—are especially drawn to Gregg’s mistflower (Conoclinium greggii) due to a fascinating chemical interaction that plays a role in their mating behavior.

After consuming these compounds, the males convert them into sex pheromones that are stored in specialized scent patches on their wings, known as androconial organs. During courtship, the males release these pheromones to signal their fitness and appeal to potential mates.

Why Gregg’s Mistflower Is a Preferred Choice

Gregg’s mistflower stands out among native plants because of its particularly high alkaloid content. This makes it a key resource for male butterflies seeking the chemicals necessary for pheromone production. In addition to its chemical properties, Gregg’s mistflower boasts a long blooming season and dense clusters of lavender-blue flowers, providing an abundant nectar source. This combination of chemical and nutritional benefits makes the plant exceptionally attractive to male butterflies, serving both their reproductive and dietary needs.

Monarch RX

A new citizen-science project, Monarch Rx, explores this little-known behavior in monarch butterflies called PA-pharmacology, where they scratch at and sip from leaves of non-milkweed plants containing pyrrolizidine alkaloids (PAs). These compounds, found in plants like boneset and mistflowers, provide defense against predators and potentially aid in mating and disease resistance.

The project invites the public to report observations of this behavior to gather data on plant diversity and frequency of PA-gathering. Collaborators hope this initiative will shed light on an overlooked aspect of monarch butterfly behavior and inspire further research into their association with PA plants.

Check out the Monarch Rx project on CitSci.org, where you’ll find links to the paper, a one-page primer about the topic, and a place to put on record the many observations we hope you’ll make.

Quick Links to More Info:

Read the paper in Ecological Entomology: The puzzle of monarch butterflies (Danaus plexippus) and their association with plants containing pyrrolizidine alkaloids

Read the paper in News of the Lepidopterists’ Society: Monarch butterflies gather pyrrolizidine alkaloids from dead and injured plants: a call for citizen science contributions

Read the article in Entomology Today: New Citizen-Science Project Explores Little-Known Behavior in Monarch Butterflies

Read the article in the Wild Ones Journal: Monarch Rx: Butterflies Obtain “Drugs” from Withering Plants

Listen to the podcast with Joe Lamp’l of Joe Gardener: Monarch Rx: The Prescription for Healthier Butterflies

Read the primer: Summary and Fact Sheet about Monarch and PAs

 

 

 

Have you ever wondered a migrating monarch can fly up to 2,500 or sometimes even 3,000 total miles from Canada and Northern United States and find the exact location they need to find in Mexico to overwinter? None of the monarchs on the fall migration path have ever been to their destination before, and yet they know exactly where to go.

Monarch butterflies know to migrate south because their genes give them an internal “clock” and instructions for navigation. They use a complex system involving a time-compensated sun compass, a circannual clock, and possibly Earth’s magnetic field to fly south. Specialized cells in their antennae and eyes help process these cues, enabling them to fly in the correct direction even on cloudy days to reach overwintering grounds in Mexico, a place they’ve never been before.

Internal Clock in the Antennae

Monarchs use a circadian clock located in their antennae to track time of day. This clock syncs with the position of the sun, allowing them to use a “sun compass” in their brain to determine direction. Without this timekeeping mechanism, they’d misinterpret the sun’s position and veer off course.

The brain integrates signals from the antennae’s clock with visual cues from the sun. This coordination helps monarchs maintain a southward trajectory toward their overwintering sites in Mexico.

So in essence, monarch antennae are like nature’s GPS satellites, keeping time, syncing with celestial cues, and guiding these tiny travelers thousands of miles with astonishing precision.

References:

• _{Butterfly ‘GPS’ found in antennae, by Judith Burns, BBC News, September 25, 2009. Accessed online June 8, 2015.}
• _{Scientists show that monarch butterflies employ a magnetic compass during migration, by Jim Fessenden, UMass Medical Schools, June 24, 2014. Accessed online June 8, 2015.}
• _{Antennal Circadian Clocks Coordinate Sun Compass Orientation in Migratory Monarch Butterflies, Christine Merlin, Robert J. Gegear, And Steven M. Reppert, Science 25 September 2009: Vol. 325. Accessed online June 8, 2015.}

 

 

If a pipevine swallowtail flutters through your garden, prepare to be spellbound by shimmering iridescent blue hindwings. The wings truly are beautiful but they do serve an important role in protecting the butterfly from predators. The wings are a warning that this butterfly is toxic. Pipevine swallowtails pack a toxic wallop because they ingest poisons from their food plant, Dutchman’s pipe.

The pipevine swallowtail  (Battus philenor) can be found across North America, spanning from the southeastern United States up into Canada and south into Central America. Specifically, they can be found in the eastern and southern United States, extending west to Arizona and with an isolated population in central and northern California. They are also found in southeastern Ontario, Canada, and southward into Mexico and northern Central America.

Pipevine swallowtails prefer warm climates and are commonly found in open woodlands, meadows, and gardens. They are particularly attracted to areas where their host plant, the pipevine (Aristolochia), grows.

Host Plant Relationship: Aristolochia Bond

Pipevine swallowtails feed on Aristolochia (pipevine), a plant rich in aristolochic acid. This toxin makes the butterfly unpalatable to predators—nature’s way of saying “look, but don’t bite”. The caterpillars store aristolochic acids from the plants, and render themselves, their pupae form, their adult form, and their future eggs distasteful and toxic —a brilliant defensive strategy.

Species such as the spicebush swallowtail, Eastern black swallowtail, red-spotted purple, and female Eastern tiger swallowtails have developed similarities in appearance to pipevine swallowtail butterflies. This mimicry functions as a method to reduce predation by causing predators to perceive them as potentially toxic.

Lifecycle

Pipevine swallowtail females search for pipevine plants when it’s time to lay their eggs, and they often lay clusters of reddish-brown eggs on young leaves or stems.

Pipevine caterpillars display a striking black coloration accented by red spines and dorsal spots, making them particularly unappealing to would-be predators. Their hues can shift with temperature—warmer conditions often deepen their tones from black to reddish shades.

The caterpillars are gregarious in their early days, which means they hang out in groups feeding together. When they get a bit bigger, they tend to go their own way. As the pipevine caterpillar grows, its appearance starts to change as well. It slowly becomes darker and has more pronounced dots of color and longer black tubercles on the front of their heads, which look like antennae.

The chrysalis of Battus philenor can be recognized by its segmented, inward-curving posterior end. Its ventral thorax arches upward, and the head bears a pair of horns on the anterior dorsal side. Remarkably, even in this vulnerable stage, the butterfly appears to deter predators with its formidable form.

Adult Pipevine swallowtail might appear black at first glance. Its upper wings are velvety black, absorbing light like charcoal silk. The hindwings—the rear pair of wings—shimmer with iridescent blue or blue-green, colors especially vivid in males and glowing even brighter under sunlight. The edges of the wings are scalloped, meaning they have a gently wavy outline that gives the butterfly a soft, undulating silhouette as it moves.

Males have iridescent blue hindwings, minimal white spotting. Often more vibrant in sunlight.

The bottom half of the ventral hindwing of both sexes is metallic blue. A single row of seven orange spots and small pale, cream dots are found at the edge of the wing embedded in the blue section. This is the pipevine swallowtail’s most identifiable characteristic.

 

Each stage of the pipevine swallowtail mirrors themes of growth, vulnerability, and renewal. From the egg’s quiet promise to the adult’s shimmering flight, the pipevine swallowtail embodies resilience and transformation.