So why would you want to be able to identify Milkweed?
You may have read in my last blog post that becoming a citizen scientist is one important way that you can help the Monarchs. There are many projects dedicated to monitoring Milkweed populations and they are in of need citizen scientists such as yourself!
Now, the first step to becoming a citizen scientist and participating in a Milkweed monitoring survey, is being able to identify the Milkweed in your area. Luckily, Milkweed is very easily identifiable by its flowers and fruits. With just a few simple hints, you will be able to find and confidently identify Milkweed. Even if you aren't positive on the species, many surveys are just looking for general Milkweed plant populations.
The patterns method
I highly recommend the "patterns method" of identifying plants that Thomas Elpel covers in his book
Botany In a Day. It is a quick and fun way to learn how to identify hundreds of plants in a short amount of time. Botanists and taxonomists have created a filing system based on these patterns. Once you can identify these key similarities in a plant family, you are able to identify the species of the plant much faster.
Image from Thomas J. Elpel's Botany in a Day
For instance, plants in the milkweed family, Asclepiadaceae, (don't let the name intimidate you), secrete a milky sap (except for Butterfly Milkweed) and opposite or sometimes whorled leaves. There are 5 separate sepals (petal-like leaves) and 5 fused petals. The corona (circle of petals around the center of the flower) contains 5 hooded forms facing inwards. Inside the corona there are 5 stamens (male parts) fused to the ovary (female part). The pods are filled with many seeds with silky tufts.
Butterfly Milkweed- Asclepias tuberosa
Stem: 20 to 60 cm tall.
Flowers: bright orange-yellow, arranged in umbels.
Leaves: alternate on the stem (not opposite each other), lance-shaped, 5 to 10 cm long, smooth on top and downy beneath.
Habitat: limestone soils, open, rocky, dry sites. Does not tolerate shade.
Unique feature: no milky sap.
Butterfly milkweed (Asclepias tuberosa). Photo by Larry Stritch.
Swamp Milkweed- Asclepias incarnata
Stem: Downy (hairy), from 60 to 200 cm tall.
Umbels: Red or purplish-pink.
Leaves: Narrow, tapered, 4 to 17 cm long, arranged in opposite pairs.
Fruits: Long, narrow and smooth follicles, changing colour from green to brownish.
Habitat: Wetlands. Also found in swamps, ditches and near streams, rivers and lakes.
Population: Often scattered – does not form dense colonies.
Swamp milkweed Photo courtesy of Jennifer Anderson, USDA-NRCS PLANTS Database.
Common Milkweed- Asclepias syriaca
Stem: downy, usually single, 90 to 120 cm tall. Underground stems.
Leaves: broad and thick, 10 to 20 cm long, arranged in opposite pairs on the stem and with pubescent undersides.
Flowers: pale pink or violet, arranged in almost spherical umbels.
Fruits: large spindle-shaped fruit, bumpy, rough and downy.
Habitat: poor, dry soil, disturbed, sunny sites.
Whole plant with flowers. Photo by David Taylor.
Showy Milkweed- Asclepias speciosa
Stem: 45 to 200 cm tall, velvety or pubescent (hairy).
Flowers: Pale pink, arranged in umbels. The corona hoods are long (9 to 13 mm) and lance-shaped, making the flowers look like stars.
Leaves: Opposite, 10 to 25 cm long, smooth or slightly downy.
Habitat: Well-drained soil, sunny sites, pastures, forest edges,untilled fields, roadsides, ditches.
Showy milkweed (A. speciosa). Photo: Sarina Jepsen/Xerces Society
Elpel,Thomas-Botany in a Day http://www.wildflowers-and weeds.com/Plant_Identification/Patterns_in_Plants.htm Mission Monarch- Milkweed sheet
Monarch Mission. http://www.mission-monarch.org/wpcontent/uploads/2017/07/FICHES_ASCLE%CC%81PIADE_ANG_FINAL.pdf Thomas G. Barnes, hosted by the USDA-NRCS PLANTS Database / Barnes, T.G., and S.W. Francis. 2004. Wildflowers and ferns of Kentucky. University Press of Kentucky.
USDA Forest Service. Plant of the Week. https://www.fs.fed.us/wildflowers/plant-of-the-week/asclepias_syriaca.shtml