Milkweed Is on the Menu!
Monarch butterfly populations have declined by a shocking 90% over the past 20 years! One thing we can do is to plant native milkweed. Not only does it provide nectar for the adult butterflies, but also it is the only plant on which they will lay their eggs. Learn more about which milkweed varieties are best for Monarchs!
The Missing Monarchs
What has happened to our Monarch butterflies? Many factors have contributed to this horrific loss, including climate change, weather extremes, loss of winter habitat in Mexico, and widespread use of pesticides. While these are problems that will take years to change, one thing we can do in our own yards today is use less or no chemicals. A very easy thing we can do is to plant milkweed!
Not only will you help these valuable pollinators, but you’ll treasure the presence of fluttering friends in the garden!
Milkweed is the only food Monarch “babies” eat! It’s that simple. When the caterpillars hatch out, they can start feeding immediately on the milkweed leaves. Toxins in the plant make the adult Monarchs and their larvae taste bitter to predators, protecting them from hungry birds. It is such an effective deterrent that other butterflies, such as the similarly-colored Viceroy, are also avoided by predators just in case they are bitter too. If you decide to grow milkweed in your yard, be aware that the cardiac glycosides contained in the plants are toxic to pets and people also.
Milkweed Varieties
The milkweed genus (Asclepias) is fairly large, with 73 species native to the US and over 100 in North America. They support 12 species of butterflies and moths, including the Monarch. Choose ones that are native to your region and are right for your situation. Here are a few to consider; they have wide native ranges and are frequently available as seeds or plants:
Common milkweed smells so sweet they should make a perfume from it!
- Common milkweed (Asclepias syriaca) is a hardy perennial that will thrive almost anywhere in the US, especially east of the Rockies and into Canada. It needs sun, reaches 2 to 6 feet tall with wide, gray-green, velvety leaves, and is an aggressive grower. Don’t plant this in your flowerbed or it will take over. It has a wide-spreading root system and needs an area all its own, where it can really stretch out. It has pale purple-pink flowers that are very fragrant and attract many pollinators in addition to Monarchs.
Butterfly weed is a bright spot in the garden that attracts all kinds of pollinators.
- Butterfly weed (A. tuberosa) is less aggressive than its common cousin, growing only 1 to 2-1/2 feet tall. It is commonly grown in gardens, adapts well to moist or dry soil, and its orange flowers are very showy. It likes full sun and is hardy in Zones 3 to 9.
Swamp milkweed has thinner leaves and more colorful flowers than common milkweed.
- Swamp milkweed (A. incarnata) is also more well-behaved than common milkweed, forming clumps rather than spreading out. It grows 2 to 4 feet tall, has deep rose-pink flowers, and is shade tolerant. It will grow in wet soil near lakesides or damp marshlands, but also grows well in average garden soil and is hardy in Zones 3-9.
- Showy milkweed (A. speciosa) is native from west of the Mississippi into California and north to Canada. It has pastel pink flowers on 2- to 4-foot tall plants. It is drought tolerant, making it a good plant for arid plains and prairie-lands, though it grows well in moist garden soils as well. It needs full sun and is hardy in Zones 3-9.
See maps showing the native ranges of many types of milkweed.
Two No-Grows
There are some milkweeds that are not beneficial to Monarchs. Gardeners in southern states should avoid planting tropical milkweed (A. curassavica). It is a beautiful plant with bright yellow/red/orange flowers, but it hosts a parasite that infects the caterpillars and weakens the butterflies when they emerge from their chrysalis. Since the plants don’t die back until late into winter, the Monarchs stay there until it is too late to make their yearly trip to Mexico. Learn more about Monarch butterfly migration.
Black Swallow wort. If you see this growing, pull it out! (Photo from UNH Extension)
Another no-grow is climbing milkweed (Cynachum nigrum), also called black swallow-wort. It is an incredibly invasive twining weed in the milkweed family. If a Monarch lays her eggs on it, those caterpillars won’t grow large enough to turn into butterflies. It is a tough one to get rid of, since it spreads by wind-blown seeds and has a large root crown and deep roots.
Becoming a Way Station
Planting milkweed and other native wildflowers, especially late season nectar plants such as goldenrod and asters, will add to the survival chance of visiting monarchs and other pollinators by acting as an energy source and a shelter for adults, as well as host plants for larvae.
You can create a Monarch Way Station in your backyard in a 100 sq. ft. sunny space with well-drained soil. Plant at least 10 plants of two or more flower species native to your region that flower at different times, including some milkweed. Once it is up and growing, register it at MonarchWatch.org. Over 31,000 gardeners across the country have done it so far!
One reader said, “Think of it as an Airbnb for butterflies!”
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Considering my photo documentation of the Monarch (30,000) I have been considering donating to the NH Audubon in Concord NH where I gave many lectures and had an exhibit (NH Public TV had a program on it). keeping things local.
More info about the Monarch:
1) The Mexico wintering areas were first discovered and an article in the August 1976 magazine describes the finding. A Monarch was found with a tag showing it came from Minnesota.
2) The Monarch Watch at the Univ of Kansas Chip Taylor has that program and has materials for school kids including the tagging and tracking.
3) There are two "societies" of Monarchs, the Eastern and the Western The Eastern migrates to Mexico. The Western migrate to Pacific Grove CA.
4) The Monarch winter sites are in danger. The three Mexican sites by logging. The Western by ignorant town officials that permitted the cutting of the trees Monarch's winter over in. A PBS program is about this and the people trying to replant the special trees. I have contacted them.
5) I have also contacted some professors (involved with Monarchs) in universities (WA & MN) about my status knowing the Monarch. Was given the cold shoulder. Guess they didn't like a person that financially his own studying and wasn't a scholar with grants. Who are they helping????
6) There are easy methods of determine a male & female. A male has narrow black veins on the wings and a dark spot on the two lower wings. A female has wider veins, no spot. Also being some distance, observe them in a field. The female is going and landing on the milkweed laying eggs underside the leaves. The male has a Life of Reilly, going from any flower to flower.
7) At the Prescott Park in Portsmouth NH the Monarchs favored one flower type, the Tithonia (Mexican Sunflower). Has a convenient landing platform to drink the nectar and perhaps a favorite color.
8) The life cucles are: It takes about 5 generations for the Monarch to arrive in the VT-NH and northern areas, leaving Mexico in February, arriving about the end of June for the nice young tender milkweed.
Takes two weeks from egg laying to hatching. Usually in August they are ready to return to Mexico, being some five generations of not being there. How do they know? If studying, it's determined "what is so small is so huge".
9. My pics captured the young caterpillar inside the egg having a black head. The first thing they consume is the egg shell, then traveling to the top tender leaves of the plant.
10) MA and some states in the mowing of road sides have allowed the Milkweed alone for the Monarchs. I've given the seeds to peolle. Milkweed is also a great plant to eat.
Just some of my observations, capsulized in short form. Think about it.
Very interesting about two sociities of Monarch Butterflies; Eastern to Mexico + Western to California; Ill get some Tithonia (Mexican Sunflower); thanks again: (I have native Milkweed):
After the Hummer family left the Monarch Catapiller showed up at the swim pool house they opened up for the public to watch activity. It took Catty 3 days to settle down in the cage to build the Cocoon. I watched 24-7 it was fascinating. Built the most beautiful Turquoise w Gold Beads spun around it till hatch time. Under the Orange we ese on wing, it was deep Blood Red so beautiful. The Aphids totally killed my Milkweed a few yrs ago, going to plant some . thank you for your article
To Tom Chase: I'm pretty sure the Smithsonian Institute would want the Butterfly Collection; contact them; ty~
Your comments about Tropical milkweed have been found to be incorrect. Research by Jaap de Roode’s lab at Emory University, confirmed that butterflies that are infected by OE tend to prefer the tropical milkweed even more than usual. However the tropical milkweed has been found to be “medicinal” in terms of improving parasite resistance suggesting that they are self medicating their offspring. In the final analysis they determined the effect is certainly real. This is not to suggest that you should only plant tropical milkweed but some balance of the two to help them fight OE.
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