Table of Contents for Monterey, California Milkweeds
There are ten species milkweeds (Asclepias spp.) that are native or nearly native in the Monterey, CA area that can be grown for butterflies and other insects. Milkweeds are an important host species for monarch and queen butterflies and a nectar species for other insects. The monarch and queen butterflies use the cardenolides found in the milky sap of milkweeds to give an unpleasant taste to predators. These plants are also an important nectar source to all insects visiting your pollinator garden. Seeds for a number of Monterey milkweeds can be purchased in the McMullen House garden shop.
Location of Monterey, California
Monterey, California is located at the south end of Monterey Bay in northern Monterey County. Just to the west, and adjacent to Monterey is Pacific Grove, CA, which is called “Butterfly Town, USA,” due to the fact that monarch butterflies in California overwinter there after migrating from the mountains.
USDA Plant Hardiness Zones in Monterey, California
Monterey, California is located in zone 10a. Just to the east, going inland, is zone 9b. When selecting plants you will want to plant those that can handle temperatures as cold as +30F in Monterey and +25F in inland areas to be sure they will survive.
Butterflies in Monterey, CA that are Hosted by Milkweeds
Monarch Butterfly (Danaus plexippus)
The Monarch Butterfly is one of the most iconic butterflies in North America and is a bellweather of changes in the environment. Having a distinctive orange color with black stripes, this butterfly has a wingspan of 3 in (7.6 cm) to 5 in (12.7 cm). The monarch butterfly ingests the toxic cardenolides of the milkweed plants, making it distasteful to predators. It can have several broods in a year and is known for its migrations to Mexico each year. However, some populations in the south, such as southern California, Arizona, and Florida do not migrate and breed year-round (Urguhart, et al 1968).
Queen Butterfly (Danaus gilippus)
The Queen Butterfly is similar to the Monarch Butterfly but is more of a solid orange color and has a brownish hue, especially along the edges. When the wings are closed and the underside is shown it looks almost alike and is hard to tell apart. However, this butterfly is generally smaller than the monarch having a wingspan of 2.5 in (6.4 cm) to 4 in (10.2 cm). The similarity is not by accident and the queen butterfly is a mimic of the monarch, but it also ingests the cardenolides of the milkweed plants. Unlike the monarch this butterfly does not migrate and in the Monterey area is a stray from the south.
1. White-stem Milkweed (Asclepias albicans), a Milkweed for Dry Soils
White-stem Milkweed (Asclepias albicans): White-stem milkweed is native to the southern counties of California (Kartesz 2015). In the wild, white-stem milkweed grows in dry areas such as deserts and gravelly, sparsely vegetated places. Growing from 4 to 12 feet tall, this milkweed is the tallest and one of the only shrubby milkweeds in North America. The greenish to white flowers bloom from September to June. It is hardy in zones 9-11. This species is native to the south of the Monterey area, but can handle the hardiness zone.
In your Monterey butterfly garden, this milkweed is hardy in zones 9-11 and requires full sun and sandy to rocky dry soils.
2. California Milkweed (Asclepias californica), a Milkweed for Dry Sandy Soil
California Milkweed (Asclepias californica): California milkweed is native only to the state of California and adjacent areas of northern Mexico. It has two subspecies, subsp. californica, which is found in the southern counties of the state, and subsp. greenei, which is found in the central and northern counties of the state (Kartesz 2015). In the wild, California milkweed is grows in open areas with disturbance such as fields, pastures, and roadsides, and woodlands. Growing from 2 to 4 feet tall, the flower colors are widely variable and include white, pink, lavender, green, purple, or red and bloom from March to July.
Subspecies greenei is the only subspecies that is native to Monterey, however, both subspecies can exist in the hardiness zone.
In your Monterey butterfly garden, this milkweed is hardy in zones 7-10, requires full sun and dry sandy or clay soils.
3. Heart-leaf Milkweed (Asclepias cordifolia), a Milkweed for Mesic to Dry Soils
Heart-leaf Milkweed (Asclepias cordifolia): Heart-leaf milkweed is native in the central and northern counties of California (Kartesz 2015). In the wild, heart-leaf milkweed grows in woodlands and talus slopes. Growing from 1 to 4 feet tall, the purple, lavender, to red flowers bloom from March to August. This species is native to the east and north of Monterey, but can exist in the hardiness zone.
In your Monterey butterfly garden, heart-leaf milkweed is hardy in zones 7-10, requires full sun to partial shade and mesic to dry well-drained soil. Seeds of Heart-leaf Milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.
4. Pallid Milkweed (Asclepias cyptoceras), a Milkweed for Dry Sandy/Rocky Soils
Pallid Milkweed (Asclepias cryptoceras): Pallid milkweed is native to two counties in the eastern part of the state (Kartesz 2015). In the wild, pallid milkweed grows in sandy washes and canyon bottoms (Jepson eflora), as well as, talus slopes (Baker 1971). Growing from 0.4 to 1 foot tall, the yellowish-green (Woodson 1954) to cream-white (Heil, et al 2013) flowers bloom from April to June.
This species is native well to the east of Monterey in the Sierra Nevada range, but can exist in the hardiness zone. However, because it can exist in a much lower hardiness zone, it may be stressed in time with warming due to climate change.
In your Monterey butterfly garden, this milkweed is hardy in zones 6-10, requires full sun and dry or rocky sandy soils.
5. Woollypod Milkweed (Asclepias eriocarpa), a Milkweed for Mesic to Dry Soils
Woollypod Milkweed (Asclepias eriocarpa): Woollypod milkweed is native throughout the state (Kartesz 2015). In the wild, woollypod milkweed grows in dry areas with full sun including deserts, roadsides, fields, and rocky hillsides. Growing from 2 to 4 feet tall, the greenish to yellowish-white (Woodson 1954) or pink (Calscape) flowers bloom from May to October.
This species is native to the Monterey area, but may become more heat stressed over time due to climate change warming. The eastern suburbs of Monterey have the best chance of growing this plant.
In your Monterey butterfly garden, this plant is hardy in zones 4-9, requires full sun to partial shade and mesic to dry well-drained soil. Seeds of woollypod milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.
6. Desert Milkweed (Asclepias erosa), a Milkweed for Dry Sandy Soils
Desert Milkweed (Asclepias erosa): Desert milkweed is native to the central and southern counties of California (Kartesz 2015). In the wild, desert milkweed grows in washes, roadsides, and sandy plains. Growing from 1 to 4 feet tall, the white, cream, green, to yellow flowers bloom from April to October.
This species is native to the south of Monterey, but can grow in the hardiness zone. However, since it can grow in a much lower hardiness zone, it may become more stressed over time with climate change warming.
In your Monterey butterfly garden, this milkweed is hardy in zones 4-10, require full to partial sun and dry sandy soils. Seeds for desert milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.
7. Narrow-leaf Milkweed (Asclepias fascicularis), a Milkweed for Poor Well-drained Soils
Narrow-leaf Milkweed (Asclepias fascicularis): Narrow-leaf milkweed is native throughout California (Kartesz 2015). In the wild, narrow-leaf milkweed grows in dry open areas such as grasslands, roadsides, woodlands, and disturbed areas. Growing from 1 to 3.5 feet, the grayish-pink to white (Woodson 1954), lavender (Calscape), white to peach (Ljubenkov and Ross 2002) or greenish-white (Jepson eflora) flowers bloom from May to October.
This species is native to the Monterey area, but may become more stressed from climate change warming in the future.
In your Monterey butterfly garden, this milkweed is hardy in zones 6-10, requires full sun and poor well-drained soils. Seeds of narrow-leaf milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.
8. Showy Milkweed (Asclepias speciosa), a Milkweed for Mesic to Dry Soil
Showy Milkweed (Asclepias speciosa): Showy milkweed is native in the central and northern counties of the state (Kartesz 2015). In the wild, showy milkweed grows in open areas such as roadsides, fields, and woodlands that are mesic to dry. Growing from 1 to 3 feet tall, it has flowers that are purple to pink in color and bloom from April to June.
This species is native to the north and east of Monterey and could potentially be grown in the eastern suburbs. Since it is at the edge of its hardiness zone, it may be heat stressed now and in the future.
In your Monterey butterfly garden, this plant is hardy in zones 3-9, requires full sun and soils that mesic to dry. Seeds of showy milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.
9. Rush Milkweed (Asclepias subulata), a Milkweed for Dry Soils
Rush Milkweed (Asclepias subulata): Rush milkweed is native to the southern counties of California (Kartesz 2015). In the wild, rush milkweed grows in open areas with full sun such as washes and arroyos (Jepson eflora), benches of slopes (Roberts, et al 1998) desert areas (Shreve 1936), sandy flats (McLaughlin 1987), and roadsides (Felger 2014). Growing from 3 to 6 feet this plant has flowers that are yellowish-white to cream that bloom year-round.
This species is native to the south of Monterey, but it can grow in the hardiness of Monterey. In time, this species may actually do better in Monterey since it requires warmer temperatures and would be a climate-smart plant.
In your Monterey butterfly garden, this milkweed is hardy in zones 9-11, requires full sun and dry sandy/gravelly soils.
10. Woolly Milkweed (Asclepias vestita), a Milkweed for Well-drained Soils
Woolly Milkweed (Asclepias vestita): Woolly milkweed is native to the central and southern counties of California (Kartesz 2015). In the wild, woolly milkweed grows in dry plains, canyons, and chaparral. Growing from 1.5 to 3 feet tall, this plant has yellowish-white or greenish-white flowers with a purple tint that bloom from April to July. This species is native to the Monterey area, but is at the limit of its hardiness zone. Over the long term it will likely do best in the inland areas.
In your Monterey butterfly garden, this milkeed is hardy in zones 7-10, requires full sun and well-drained soils.
Some Notes on other Milkweeds not Native to the Area
1. Tropical Milkweed (Asclepias curassavica)
Tropical Milkweed (Asclepias curassavica): Tropical milkweed is adventive (not native, but naturalized) in the southern parts of the state (Kartesz 2015). The flowers, which bloom from June to October, are colored bright orange, yellow, or red. Tropical milkweed is planted in gardens and grows in other plances of disturbance. It is hardy in zones 8-11 and can exist in the Monterey area. However, this plant can actually harms the monarchs and is not recommended as a host plant for them.
3. African Milkweed (Asclepias fruticosa)
African Milkweed (Asclepias fruticosa): African milkweed is exotic in the central and southern coastal counties of the state (Kartesz 2015). The flowers, which bloom from December to July, are colored white or pink. African milkweed is planted in gardens and other disturbance places, but according the Jepson flora (Jepson eflora) it is not spreading. It is hardy in zones 8-11. While this species can exist in the Monterey area, it is not recommended to plant it since it is exotic to the area.
When selecting your Monterey milkweed, be sure to make sure that it grows in particular conditions (sun exposure and soil) you have in your garden.
Books where you can find out more about Monarchs and Butterfly Gardening in the Monterey, CA Area
- Case, Jonathan. 2022. Little Monarchs. Holiday House. 256 pp.
- Dumas, Jessica. 2020. Monarch Butterfly 101: Learn about Monarch Butterflies in One Sitting. Howexpert. 58 pp.
- Edenholm, Stephanie Turcotte. 2021. The Perfect Place. Stephanie Turcotte Edenholm. 36 pp.
- Hamilton, Patricia. 2022. Monarchs in Butterfly Town U.S.A., Pacific Grove, California. Pacific Grove Books. 96 pp.
- Pyle, Robert Michael. 2014. Chasing Monarchs – Migrating with Butterflies of Passage. Yale University Press. 319 pp.
- Sovak, Jan. 1993. Butterflies Coloring Book – Dover Nature Coloring Book. Dover Publications Inc. 48 pp.
Affiliate Disclosure: When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission at no extra cost to you. Affiliate programs include, but are not limited to, the eBay partner network and Blackwell’s Books.
References for Monterey Milkweeds
- Baker, William H. 1971. Noteworthy Records of Western Plants. Madrono 21: 199-200.
- Heil, Kenneth D., Steve L. O’Kane, Linda Mary Reeves, and Arnold Clifford. 2013. Flora of the Four Corners Region: Vascular Plants of the San Juan River Drainage, Arizona, Colorado, New Mexico, and Utah. Monographs on Systematic Botany – Missouri Botanical Garden v. 124.
- Kartesz, J.T. The Biota of North America Program (BONAP). 2015. Taxonomic Data Center. Link to website. Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]
- Ljubenkov, Julie A. and Timothy S. Ross. 2002. An Annotated Checklist of the Vascular Plants of the Whittier Hills, Los Angeles County, California. Crossosoma 27(1): 1-23.
- McLaughlin, Steven P., Janice E. Bowers, and Kenneth R.F. Hall. 1987. Vascular Flora of Eastern Imperial County, California. Madrono 34: 359-378.
- Roberts, Fred M., Grant Fletcher, Steve Boyd, Andrew C. Sanders, Peter Lesica, Peter Husby, Stephen V. Cooper,and Job Kuijt. 1998. Noteworthy Collections. Madrono 45: 326-330.
- Shreve, Forrest. 1936. The Transition from Desert to Chaparral in Baja California. Madrono 3: 257-264.
- Urguhart, Frederick Albert, Norah Roden Urguhart, and Francis Munger. 1968. Population of Danaus plexippus in Southern California. Journal of Research on the Lepidoptera 7(4): 169-181.
- Woodson, Robert. 1954. The North American Species of Asclepias L. Annuals of the Missouri Botanical Garden 41: 1-211.
