# Common Milkweed (Asclepias syriaca)

> The species that feeds the eastern monarch migration. Big paddle-shaped leaves, thick stems and heavy, drooping balls of dusty-pink flowers with a scent people describe as honey and vanilla. It is also an aggressive rhizomatous colonizer: magnificent in a meadow, a menace in a perennial border.

Source: https://milkweedusa.com/species/common-milkweed/  
Licence: CC BY 4.0 (Milkweed USA)

## Summary

The species that feeds the eastern monarch migration. Big paddle-shaped leaves, thick stems and heavy, drooping balls of dusty-pink flowers with a scent people describe as honey and vanilla. It is also an aggressive rhizomatous colonizer: magnificent in a meadow, a menace in a perennial border.

## Key facts

| Field | Value |
| --- | --- |
| Scientific name | Asclepias syriaca L. |
| Genus | Asclepias |
| Family | Apocynaceae |
| Common names | Common Milkweed, Silkweed, Virginia Silkweed |
| Status | Native |
| Height | 3 ft–6 ft |
| Spread | 2 ft–10 ft |
| Flower color | pink, mauve, white |
| Bloom period | June to August |
| Light | Full sun, Part shade |
| Soil moisture | Dry, Average |
| USDA zones | 3-9 |
| Leaf arrangement | opposite |
| Leaf shape | oblong |
| Sap | Milky latex |
| Root system | Rhizomatous, spreads by root |
| Seed stratification | 30 days cold-moist |
| Monarch value (0-5) | 5 |
| Garden value (0-5) | 2 |
| Nectar value (0-5) | 5 |
| US states recorded | Alabama, Arkansas, Colorado, Connecticut, District of Columbia, Delaware, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, Montana, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Virginia, Vermont, Wisconsin, West Virginia, Wyoming |

## Identification

- Leaves are large, broad and oblong with a prominent pale midrib, felted underneath.
- Flower clusters droop or nod rather than sitting flat on top of the stem.
- Stems are stout, usually unbranched, and covered in fine downy hair.
- Seed pods are fat, warty and covered in soft spines, unmistakable in the fall.

## Ecology

No plant supports more eastern monarch caterpillars. Large, soft leaves let a single stem raise several larvae, and dense colonies give females an easy target from the air. The flowers are among the richest nectar sources in the North American flora, feeding honey bees, bumble bees, wasps, beetles and butterflies through midsummer.

## Growing

Do not plant it in a small garden unless you intend to fight it. Rhizomes travel several feet a year and shoots pop up through lawns, paths and neighboring beds. In a meadow, hedgerow, ditch or dedicated monarch patch it is the best thing you can grow. Cut stems flush in the fall if you need to slow it, or grow it inside a sunk barrier.

## Cautions

Toxic to livestock in quantity, though animals normally avoid it. The tough rhizomes make it a listed noxious weed in a few jurisdictions, so check locally before establishing it on agricultural land.

## Questions

**Is common milkweed invasive?**

It is native across eastern and central North America, so it is not invasive in the technical sense, but it is genuinely aggressive. Rhizomes spread several feet per year and it will colonize a bed. Site it where it can run.

**How do I stop common milkweed spreading?**

Plant it inside a buried root barrier at least 18 inches deep, or grow it in a bottomless container sunk in the ground. Cutting shoots at ground level as they appear will weaken a colony over several seasons.

**Common milkweed or showy milkweed: which should I plant?**

Longitude decides it. East of the Rockies, common milkweed. West of roughly the 100th meridian, showy milkweed (A. speciosa) is the regional equivalent and the better choice.

## References

- Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:319076-2
- GBIF: https://www.gbif.org/species/3170247
- iNaturalist: https://www.inaturalist.org/taxa/47911
- Wikipedia: https://en.wikipedia.org/wiki/Asclepias_syriaca
- BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20syriaca.png
- NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20syriaca

## Photographs

- Asclepias syriaca - leaf (18716484236) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_leaf_(18716484236).jpg
- Asclepias syriaca - inflorescence (18555007128) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_inflorescence_(18555007128).jpg
- Asclepias syriaca - whole plant with seedpods (18555004978) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_whole_plant_with_seedpods_(18555004978).jpg
- Asclepias syriaca - inflorescence (18555073280) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_inflorescence_(18555073280).jpg
- 6 1 2014 milkweed (Asclepias syriaca) (Jrosenberry1, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:6_1_2014_milkweed_(Asclepias_syriaca).jpg
- Asclepias syriaca (ваточник сирийский) возле урочища Яцево (Novoklimov, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_(%D0%B2%D0%B0%D1%82%D0%BE%D1%87%D0%BD%D0%B8%D0%BA_%D1%81%D0%B8%D1%80%D0%B8%D0%B9%D1%81%D0%BA%D0%B8%D0%B9)_%D0%B2%D0%BE%D0%B7%D0%BB%D0%B5_%D1%83%D1%80%D0%BE%D1%87%D0%B8%D1%89%D0%B0_%D0%AF%D1%86%D0%B5%D0%B2%D0%BE.jpg
- Asclepias syriaca - stem (18745239231) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_stem_(18745239231).jpg
- Aphis nerii feeding on Asclepias syriaca in Almaty Botanical Garden (Ruslan Kastani, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Aphis_nerii_feeding_on_Asclepias_syriaca_in_Almaty_Botanical_Garden.jpg

## How to cite

Milkweed USA. (2026). Common Milkweed (Asclepias syriaca). https://milkweedusa.com/species/common-milkweed/