Nectar plant associations for Willamette Valley Butterflies
Of all of the notes and mini “research” projects that I have done on this substack, the one that I keep coming back to the most is the post that details all of the caterpillar host plants for the butterflies of Willamette Valley
Here I wanted to expand this concept a bit to talk about what plants butterflies are using most for their adult nectar needs. This concept isn’t nearly as precise as what plants caterpillars use to feed, as many adult butterflies are generalist feeders and will feed on native and non-native garden species alike. But some do have strong preferences, and if possible I’d like to discern what they are.
The books and websites I frequently reference (listed below) often will list specific plants that butterfly species are most commonly seen nectaring on. Unfortunately the books don’t list out what variety of plants they are referring to. For example, they often list “clover” but they don’t say if they are referring to a native clover or a one of the many exotic and naturalized species. Still, I find there is important insight to be gleaned from the info that is presented.
Takeaways
Caveat: this is definitely not a scientific study of the topic, but I find there are some key takeaways from the information presented here.
Takeaway 1: Asters are at the top of the list for their butterfly associations.
Takeaway 2: Thistles are second to asters. Unfortunately we don’t know which thistle the authors are referring to. One can only assume, however, that native thistles are extremely important to butterflies in our region. These are a completely overlooked species in most native gardening literature and we need to work to over come this.
Takeaway 3: Of all of the other highly used plants, Dogbane (especially Spreading Dogbane) is almost never available for purchase. We need to remedy this.
Takeaway 4: Milkweed isn’t just important for Monarchs. Many species of butterflies use them as nectar plants. In my garden, it is not uncommon to find two or three swallowtails at one time feeding on a small patch of milkweed blooms.
Takeaway 5: Most highly used nectar species in descending order (5 or more notations in the literature):
Aster (27), Thistle (22), Clover (14), Goldenrod (14), Pearly Everlasting (14), Dogbane (13), Milkweed (11), Blackberry (10), Mint (8), Yarrow (8), Strawberry (7), Cinquefoil (6), Fireweed (5), Gumweed (5), Penstemon (5).
Takeaway 6: there are other slightly less commonly used species not available for purchase in gardens that should be. Toothwort, and Western Clematis are 2 that pop out of the list for me.
Plant list
Aster: Acmon Blue, American Lady, Clodius Parnassian, Common Ringlet, Common Wood Nymph, Eastern-tailed Blue, Field Crescent, Green Comma, Hoary Comma, Hydaspe Fritillary, Juba Skipper, Margined White, Milbert's Tortoiseshell, Monarch, Mormon Metalmark, Mourning Cloak, Mylitta Crescent, Ochre Ringlet, Orange Sulfur, Painted Lady, Pine White, Purplish Copper, Red Admirable, Sachem, Sonora Skipper, West Coast Lady, Western Meadow Fritillary 27 species
Balsamroot: Anise Swallowtail, Juba Skipper, Western Tiger Swallowtail
Bistort: Snowberry Checkerspot
Blackcap raspberry: cedar hairstreak
Blackberry: California Sister, Clodius Parnassian, Common Wood Nymph, Johnson's Hairstreak, Mylitta Crescent, Ochre Ringlet, Orange Sulfur, Satyr Angelwing, Western Meadow Fritillary, Western Tiger Swallowtail 10 species
Bleeding heart: Persius Duskywing
Brodiaea: Ochre Ringlet, Propertius Duskywing, Sara's Orangetip
Buckwheat: Boisduval's Blue, Cedar Hairstreak
Buttercup: Cedar Hairstreak
Camas: Anise Swallowtail, Cedar Hairstreak, Edith's Checkerspot, Propertius Duskywing
Cascara: Satyr Angelwing
Cherry: Brown Elfin, Painted Lady, Silvery Blue
Cinquefoil: Alpine Checkered Skipper, Boisduva's Blue, Eastern-tailed Blue, Margined white, Sonora Skipper, Western Meadow Fritillary 6 species
Clover: American Lady, Boisduval's Blue, Brown Elfin, Cedar Hairstreak, Eastern Tailed Blue, Monarch, Mylitta Crescent, Ochre Ringlet, Painted Lady, Purplish Copper, Red Admirable, Silver-spotted Skipper, Sonora Skipper, Western White 14 species
Collinsia: Sara's Orangetip
Coltsfoot: Anise Swallowtail, Echo Azure, Margined White, Milbert's Tortoiseshell
Columbia Lily: Clodius Parnassian, Pale Swallowtail
Columbine: Anise Swallowtail, Western Tiger Swallowtail
Currant: Brown Elfin, Echo Azure, Mourning Cloak
Dogbane: American Lady, Clodius Parnassian, Dun Skipper, Field Crescent, Gray Hairstreak*, Great Spangled Fritillary, Hydaspe Fritillary*, Lorquin's Admiral, Propertius Duskywing, Sachem, Silver-spotted Skipper*, Sylvan Hairstreak*, West Coast Lady* 13 species
*These 5 butterflies are specifically associated with Spreading Dogbane. The others do not specify which species.
Fiddleneck: Sara's Orangetip
Fireweed: Clodius Parnassian, Dun Skipper, Margined White, Red Admirable, Woodland Skipper 5 species
Fleabane: Cedar Hairstreak, Ochre Ringlet, Purplish Copper, Orange Sulfur
Gaillardia: Common Wood Nymph
Geranium: Margined White
Goatsbeard: Cedar Hairstreak
Goldenrod: Acmon Blue, American Lady, Cedar Hairstreak, Dun Skipper, Gray Hairstreak, Great Purple Hairstreak, Milbert's Tortoiseshell, Monarch, Mormon Metalmark, Mylitta Crescent, Ochre Ringlet, Orange Sulfur, Pine White, West Coast Lady 14 species
Gumweed: Anise Swallowtail, Purplish Copper, Red Admirable, West Coast Lady, Woodland Skipper 5 species
Heleniums: Sonora Skipper
Lomatium: Propertius Duskywing
Lotus: Dun Skipper
Lupine: Anise Swallowtail, Persius Duskywing
Marsh Marigold: Clodius Parnassian
Manzanita: Anise swallowtail
Milkweed: Acmon blue, American Lady, Field Crescent, Juba Skipper, Gray Hairstreak, Great Spangled Fritillary, Orange Sulphur, Red Admirable, Sachem, Silver spotted skipper, Sylvan Hairstreak 11 species
Mimulus: Sara's Orangetip
Mints: Acmon Blue, Field Crescent, Gray hairstreak, Juba Skipper, Pale Swallowtail, Purplish Copper, West Coast Lady, Woodland Skipper 8 species
Montia: Cedar Hairstreak, Clodius Parnassian, Margined White
Nodding onion: Anise Swallowtail, Gray Hairstreak
Oak sap: Mourning Cloak
Oregon Grape: Cedar Hairstreak, Johnson's Hairstreak
Pearly Everlasting: American Lady, Anise Swallowtail, Clodius Parnassian, Field Crescent, Hoary Comma, Milbert's Tortoiseshell, Mormon Metalmark, Mylitta Crescent, Oreas Angelwing, Pine White, Snowberry Checkerspot, Sylvan Hairstreak, Western Meadow Fritillary, Woodland Skipper 14 species
Penstemon: Anise Swallowtail, Common Wood Nymph, Hydsaspe Fritillary, Pale Swallowtail, Sonora Skipper 5 species
Phacelia: Edith's Checkerspot
Plectritis: Margined White
Prunella: American Lady, Boisduval's Blue, Common Roadside Skipper, Woodland Skipper
Rhododendron: Western Tiger Swallowtail
Redtwig Dogwood: Painted Lady
Ribes: Cedar Hairstreak
Salmonberry: Margined White
Sedum: Edith's Checkerspot
Spiraea: Common Wood Nymph
Strawberry: Alpine Checkered Skipper, Brown Elfin, Eastern-tailed Blue, Edith's Checkerspot, Sara's Orangetip, Two-Banded Checkered Skipper, Western Meadow Fritillary 7 species
Thistle: American Lady, Anise Swallowtail, Common Ringlet, Common Checkered Skipper, Common Wood Nymph, Dun Skipper Field Crescent, Great Spangled Fritillary, Hydaspe Fritillary, Juba Skipper, Lorquin's Admiral, Milbert's Tortoiseshell, Monarch, Pine white, Purplish Copper, Red Admiral, Sachem, Sara's Orangetip, Silver-Spotted Skipper, Sonora Skipper, Western Meadow Fritillary, Woodland Skipper, Western Tiger Swallowtail 22 species
Toothworth: Pale Swallowtail, Two-banded Checkered Skipper, West Coast Lady
Vetch: American Lady, Great-spangled Fritillary, Monarch, Propertius Duskywing
Vine Maple: Cedar Hairstreak
Violet: Echo Azure, Maringed White
Wallflower: Pale Swallowtail, Margined White
Western Clematis: Acmon Blue, Common Wood Nymph, Ochre Ringlet, Mormon Metalmark
Willow Catkins: Brown Elfin, Echo Azure
Willow Sap: Hoary Comma, Satyr Angelwing
Yarrow: Anise Swallowtail, Cedar Hairstreak, Hydaspe Fritillary, Lorquin's Admiral, Ochre Ringlet, Pine White, Western Tiger Swallowtail, Woodland Skipper 8 species
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
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