Native Butterfly Host Plants for the Willamette Valley in Oregon (listed by plant)
Doing some garden planning? Here's a list of native plants that support butterfly caterpillars.
This is a list of native butterfly plants for our area. If you’d like to a list of all known Willamette Valley butterflies and all of their documented plant associations, please see this post.
The monarch is probably the most well-known butterfly in the world. Unfortunately, its range has also declined considerably. Gardeners are becoming more and more aware that in order to have monarchs, there has to be milkweed - the only plant that the monarch caterpillar will feed on.
But did you know that all butterflies require specific plants to feed their caterpillars? These plants are called host plants, which are different than what butterflies use as nectar plants. Host plants feed the caterpillar, nectar plants feed the butterfly. Often the butterfly will nectar on its host plant, plus a whole range of other plants, which I won’t go into here.
The focus of this post will be on host plants - since there are no butterflies without caterpillars and their associated plants.
Important note: the threatened or endangered butterflies that sparsely occupy our areas aren’t covered extensively here (they are subspecies of the listed varieties below). I’ll be covering their habitat requirements, nectar plants, and host plants in a series in 2026 from whatever literature I can find. Stay tuned.
Where I mark that the plants are unspecified, it means, for example, that roses are used as host to the Mourning Cloak, Lorquin’s Admiral, and Snowberry Checkerspot, but the specific roses that are used aren’t noted in the literature available to me. This likely means that they will host on all of them, but I am not sure.
Note that I am still teasing out specifics on these plants, and the list is updated very often with information as I uncover it. There are many subarticles linked here, and I will be going into specific detail on plant families such as Ceanothus, Ribes, Buckwheat, Lupine, etc.
Donations: the information that is provided here is free for gardeners of all financial means. I feel that those who have the least resources are those who need this information most. If you’d like to financially support this site, myself and my family, you can make a one-time donation or monthly subscriptions on this link. Thank you SO much to the folks that have supported me. Your contributions mean so much!
Plant list:
Alder: Green Comma, Mourning Cloak, Pale Swallowtail, Western Tiger Swallowtail
Arabis, unspecified: Western White
Artemisia, unspecified: American Lady, Painted Lady, suspected West Coast Lady
Ash: Western Tiger Swallowtail, Snowberry Checkerspot
Aster: Field Crescent. My books list Cascade aster as a host, which does not reside in the valley. However, Art Shapiro’s site (California) lists Aster chilensis complex as acceptable hosts which do reside in our area and available in the nursery trade.
Birch/Betula: Green Comma, Mourning Cloak, Pale Swallowtail, Western Tiger Swallowtail
Bittercress/toothwort/cardamine: Margined White, Sara’s Orangetip
Blackberry: Two-banded Checkered Skipper
Bleeding hearts: Clodius Parnassian
Bluebunch Wheatgrass: Woodland Skipper
Bromes: Juba Skipper
Note: there are a few native bromes, but few in cultivation. Bromus Sitchensis is one that has seed sources available.
Buckwheats/eriogonum: Acmon Blue, Brown Elfin, Gray Hairstreak, Mormon Metal mark, Bramble Green Hairstreak
Please see this post regarding which species are especially good for Willamette Valley gardens.
Carrot family: Anise Swallowtail (69 host plants including natives and garden vegetables)
Cascara: Brown Elfin, Pale Swallowtail
Castilleja/paintbrush: Edith’s Checkerspot
Ceanothus: Brown Elfin, California Tortoiseshell, Echo Azure, Lorquin’s Admiral, Pale Swallowtail
Note: see this article for a more in-depth discussion about specific species of Ceanothus for Willamette Valley gardens.
Cedars (Western and Incense Cedar): Cedar Hairstreak
Checkermallows, unspecified: American Lady, Common Checkered Skipper, Gray Hairstreak, Painted Lady, Two-Banded Checkered Skipper, West Coast Lady
Cherry/prunus: Echo Azure, Lorquin’s Admiral, Pale Swallowtail, Western Tiger Swallowtail
Cinquefoil: Purplish Copper, Two-Banded Checkered Skipper
Note: both of these species are likely generalists on cinquefoil/potentilla, but Purplish Copper is definitely confirmed on, and has a strong association with Potentilla Anserina.
Clovers, unspecified: Clouded Sulfur, Eastern Tailed Blue, Gray Hairstreak, Orange Sulfur, Persius Duskywing
Note: the native selections of clovers that I’ve tried in my garden have all succumbed to slug damage. Please let me know if you have info re: a slug-resistant selection.
Collinsia: Edith’s Checkerspot
Fescues: Common Wood Nymph, Sonora Skipper
Geum: Two-Banded Checkered Skipper
Grasses, unspecified: Arctic Skipper, Common Roadside Skipper, Ochre Ringlet, Sachem, Sonoran Skipper
Hawthorne: Mourning Cloak, Pale Swallowtail
Huckleberry: Brown Elfin, Echo Azure
Kinnickinnick: Brown Elfin, Hoary Elfin
Licorice (American): Silver Spotted Skipper
Lonicera/Honeysuckle: Edith’s Checkerspot, Snowberry Checkerspot
Lotus: Acmon Blue, Bramble Green Hairstreak, Eastern Tailed Blue, Persius Duskywing, Silvery Blue, Silver Spotted Skipper, Western Tailed Blue
See this post for a more in-depth discussion of lotus plants.
Lupines: Acmon Blue, American Lady, Boisduval’s Blue, Eastern Tailed Blue, Orange Sulfur, Painted Lady, Persius Duskywing, Silvery Blue, Western Tailed Blue, Clouded Sulfur suspected: Gray Hairstreak, Silver-spotted Skipper, West Coast Lady
Note: see my article on more specific discussion on which lupines to use. Fender’s Blue is a subspecies of Boisduval’s. Stay tuned for a more in-depth discussion of this butterfly.
Madrone: Brown Elfin, Echo Azure
Maples, unspecified: Mourning Cloak, Western Tiger Swallowtail, suspected: Echo Azure
Manzanita (including Kinnikinnick): Brown Elfin, Echo Azure
Milkweeds: Monarch, suspected: Gray Hairstreak
Mimulus Guttatus: Edith’s Checkerspot, Mylitta Crescent, Snowberry Checkerspot,
Mistletoe (on oaks): Great Purple Hairstreak
see this article for more an interesting discussion on mistletoes of broadleaf trees.
Mistletoe (on Hemlock and Doug Fir): Johnson’s Hairstreak
Oak: California Sister, Gray Hairstreak, Propertius Duskywing, suspected Lorquin’s Admiral, Echo Azure
Oceanspray: Echo Azure, Pale Swallowtail, Lorquin’s Admiral
Orthocarpos: Edith’s Checkerspot
Pacific ninebark: suspected, echo Azure.
Pea: Clouded Sulfur, Eastern Tailed Blue, Western Tailed Blue, Silvery Blue, Orange Sulfur
Note: the Western Tailed Blue is confirmed on L. Japonicus and L. Nevadensis.
Pearly Everlasting: American Lady, Painted Lady, suspected: West Coast Lady
Penstemmon: Edith’s Checkerspot, Snowberry Checkerspot
Which penstemon Edith’s uses is unspecified. The Snowberry is confirmed on the following in the valley: L. Fructicosus, L. Rupicola, L. Davidsonii. Those aren’t terribly common in cultivation, and from my understanding they are somewhat more difficult to grow, requiring very sharply draining soils.
Polygonums: Purplish Copper, Gray Hairstreak
Note: the Gray Hairstreak is a generalist feeder polygonums. The Purplish Copper uses several polygonums. Two natives they are confirmed to use are P. punctata and P. Amphibia.
Poverty Oat Grass: Common Wood Nymph, Woodland Skipper
Poplars (cottonwoods): Lorquin’s Admiral, Mourning Cloak, Western Tiger Swallowtail
Rhododendron: Green Comma, Hoary Comma
Ribes (currant, gooseberry): Green Comma, Hoary Comma, Oreas Angelwing, Pale Swallowtail, Tailed Copper
See my post discussing specific Ribes species here.
Rockcresses: Julia’s Orange tip
Roses, unspecified: Mourning Cloak, Lorquin’s Admiral, Snowberry Checkerspot
Rumex species: Gray Hairstreak, Great Copper, Purplish Copper
Note: the Gray Hairstreak and Great Copper rumex hosts they will accept are unspecified. The Purplish Copper specifies non-native rumex species (sheep sorrel & dock).
Rushes, unspecified: Ochre Ringlet
Sedges, unspecified: Common Ringlet, Dun Skipper, Ochre Ringlet
Sedums: Brown Elfin, Gray Hairstreak
Serviceberry: Brown Elfin, Lorquin’s Admiral Pale Swallowtail
Snowberries: Snowberry Checkerspot
Spiraea, unspecified: Echo Azure, Lorquin’s Admiral, Mourning Cloak, Pale Swallowtail
Stinging Nettle: Milbert’s Tortoiseshell, Painted Lady, Red Admirable, Satyr Angelwing, West Coast Lady, Suspected Green Comma
Strawberry, unspecified: Two-Banded Checkered Skipper, Gray Hairstreak
Thermopsis: Clouded Sulfur, Persius Duskywing, Western Tailed Blue
Thistles, unspecified: American Lady, Painted Lady, Mylitta Crescent
Watercress: Margined White, Julia’s Orangetip
Western Crabapple: Brown Elfin, Lorquin’s Admiral, Mourning Cloak, Pale Swallowtail, Western Tiger Swallowtail
Willows, unspecified: Western Tiger Swallowtail, Lorquin’s Admiral, Mourning Cloak, Green Comma
Vetch/vicia: Silvery Blue, Eastern Tailed Blue, Western Tailed Blue, Gray Hairstreak, Orange Sulfur
Note: the Western Tailed Blue is confirmed to use native V. Americana and V. Gigantea. The Silvery Blue is confirmed on non-native vetches. The others are general feeders on vicia.
Violets: Western Meadow Fritillary, Great-spangled Fritillary, Hydaspe Fritillary, Zerene Fritillary (the Valley Fritillary was a subspecies of Zerene, and is now thought to be extinct in the valley).
See this post for many details of growing violets in the Willamette Valley.
Yarrow: Painted lady, suspected: Purplish Copper, Two-Banded Checkered Skipper
Resources:
Butterflies of the Pacific Northwest (book)
Life Histories of Cascadia Butterflies (book)
https://www.butterfliesoforegon.com/
www.calscape.org
www.pnwflowers.org
www.butterfliesandmoths.org
Lane County Butterflies https://www.lanebutterflies.org/
Donations: the information that is provided here is free for gardeners of all financial means. I feel that those who have the least resources are those who need this information most. If you’d like to financially support this site, myself and my family, you can make a one-time donation or monthly subscriptions on this link. Thank you SO much to the folks that have supported me. Your contributions mean so much!
You’re a badass homesteader, Amy! Thank you for this awesome piece. 🦋