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An Easy Butterfly Gardener’s Guide to Spokane, WA Swallowtail Butterflies and their Host Plants

Spokane, Washington is called the Lilac City and is located within the Rocky Mountains. It is a home for seven species of swallowtail butterflies that you can host in a butterfly garden. In this post we will explore the plants you need to turn your garden into a nursery and native nectar bar for swallowtail butterflies in your area. When you couple the host plants with milkweeds, you can do double duty and provide monarch butterflies and other insects. This guide will help you turn your garden into a fluttering paradise of swallowtail butterflies.

Spokane is located in eastern Washington State in the County of Spokane and has two plant hardiness zones. The city itself and eastern sections of the county are located in zone 7a, while the outlying portions of the county are in zone 6b.

Table of Contents for Swallowtail Butterflies in Spokane, WA

Location of the Spokane, Washington Area

City of Spokane and Spokane County in the state of Washington.
Map of Spokane and Spokane County, Washington — Public Domain from Wikimedia Commons.

Spokane, Washington is located within Spokane County in eastern Washington. This blog post covers the entire county as the Spokane area.

USDA Plant Hardiness Zones in Spokane, Washington

USDA Plant Hardiness Zone Map of the State of Washington.
USDA Plant Hardiness Zone Map (2023) – USDA Public Domain

The Spokane, WA area is located at the edge of zone 6 and 7. The northern and eastern parts of Spokane are in zone 7a, while the southern areas are in zone 6b. When selecting plants you will want to get those that can handle temperatures as cold as -5F to be sure they will survive.

Pale Swallowtail (Papilio eurymedon) and its host plants in Spokane, Washington

Green caterpillar of pale swallowtail (Papilio eurymedon) on a leaf.
Caterpillar of Pale Swallowtail — Papilio eurymedon Lucas, 1852 observed in United States of America by Dee Shea Himes (licensed under CC BY 4.0)
Pale swallowtail (Papilio eurymedon) on a red flower.
Pale Swallowtail (Papilio eurymedon) — ALAN SCHMIERER, CC0, via Wikimedia Commons
Adult pale swallowtail (Papilio eurymedon) on vegetation.
Pale Swallowtail (Papilio eurymedon) — Yellowstone National Park, Public domain, via Wikimedia Commons

Pale Swallowtail (Papilio eurymedon)

The pale swallowtail flies in the western United States. The green eggs are laid on the leaves of the host plant. The caterpillars have two color variations, first green and then the last stage is brown. The brown chrysalis looks likes bark to camouflage it (Wikipedia – Papilio eurymedon).

The black and cream colored adults have a wingspan of 3.5 in (8.9 cm) to 4.5 in (11.4 cm).

Plants that Host the Pale Swallowtail

The pale swallowtail uses members of the Buckthorn Family (Rhamnaceae) and the Rose Family (Rosaceae) as host plants. Some plants that host this species in the Spokane area include:

  • Oregon teatree (Ceanothus sanguineus): a shrub or tree
  • Tobacco-Brush (Ceanothus velutinus): a shrub or tree
  • Cascara False Buckthorn (Frangula purshinana): a shrub or tree
  • Alder-leaf Buckthorn (Rhamnus alnifolia): a shrub
  • Bitter Cherry (Prunus emarginata): a shrub or tree
  • Choke Cherry (Prunus virginiana): a shrub or tree

Leaves of alder-leaf buckthorn (Rhamnus alnifolia).
Alder-leaf Buckthorn (Rhamnus alnifolia) — Robert H. Mohlenbrock, Public domain, via Wikimedia Commons
White flowers of oregon teatree (Ceanothus sanguineus).
Oregon Teatree (Ceanothus sanguineus) — Walter Siegmund, CC BY-SA 3.0, via Wikimedia Commons

Old World Swallowtail (Papilio machaon) and its host plants in Spokane, Washington

Orange egg of old world swallowtail (Papilio machaon) on twig.
Egg of Old World Swallowtail — Zeynel Cebeci, CC BY-SA 4.0, via Wikimedia Commons
Caterpillar of old world swallowtail (Papilio machaon) on vegetation.
Caterpillar of Old World Swallowtail (Papilio machaon) — Bj.schoenmakers, CC0, via Wikimedia Commons
Adult of old world swallowtail (Papilio machaon) on white flower.
Old World Swallowtail (Papilio machaon) — Dendrofil, CC0, via Wikimedia Commons

Old World Swallowtail (Papilio machaon)

The old world swallowtail is common in the Arctic regions and in Europe and North America. In North America it flies in the midwest and western United States, including Alaska and western Canada.

The orange eggs are laid on the host plants. The caterpillar is black and white striped with orange spots.

The adult butterflies have wingspans ranging from about 2.5 in (6.3 cm) to 3.5 in (8.9 cm) and are black and yellow colored with blue markings on the hindquarters and two red eyespots. Sometimes the black coloring is washed out and more yellowish.

Plants that Host the Old World Swallowtail

The old world swallowtail utilizes plants in the Carrot Family (Apiaceae) as host plants. In the Spokane area, these include:

  • Lyall’s Angelica (Angelica arguta): a herbaceous plant
  • Western Water Hemlock (Cicuta douglasii): a herbaceous plant
  • American Cow-Parsnip (Heracleum maximum): a herbaceous plant
  • Members of the Lomatium genus
  • Mountain Sweet-Cicely (Osmorhiza berteroi)
Pink fruits of lyall's angelica (Angelica arguta).
Lyall’s Angelica (Angelica arguta) — Thayne Tuason, CC BY-SA 4.0, via Wikimedia Commons
Mountain sweet-cicely (Osmorhiza berteroi) with white flowers.
Mountain Sweet Cicely (Osmorhiza berteroi) — user12, CC BY 4.0, via Wikimedia Commons

Two-tailed Swallowtail (Papilio multicaudata) and its host plants in Spokane, Washington

Orange caterpillar of two-tailed swallowtail (Papilio multicaudata) on leaf.
Orange Caterpillar of Two-tailed Swallowtail — Whitney Cranshaw, Colorado State University, Bugwood.org, CC BY 3.0 US, via Wikimedia Commons
Green caterpillar of two-tailed swallowtail (Papilio multicaudata) on leaf.
Green Caterpillar of Two-tailed Swallowtail — Bill Bouton from San Luis Obispo, CA, USA, CC BY-SA 2.0, via Wikimedia Commons
Two-tailed swallowtail (Papilio multicaudata) on pink flower.
Two-tailed Swallowtail (Papilio multicaudata) — ALAN SCHMIERER, CC0, via Wikimedia Commons

Two-tailed Swallowtail (Papilio multicaudata)

The two-tailed swallowail flies in the western United States and Central America. The yellowish eggs are laid singly on the host plants. The caterpillar starts out black and white and then becomes orange to green. The brownish chrysalis is camouflaged to prevent predation.

The yellow and black colored adults look similar to tiger swallowtails. They have a wingspan of 3 in (7.6 cm) to 6.5 in (16.5 cm) and and differ from other butterflies in having thinner stripes and two-tails on the hindquarters, hence the name.

Plants that Host the Two-tailed Swallowtail

The two-tailed swallowtail uses members of the Rue Family (Rutaceae) and Rose Family as host plants. In the Spokane area there are no members of the Rutaceae present so it survives on species in the Rosaceae. Some species in this family in the Spokane area include:

  • Members of the Amelanchier (Serviceberry) genus: shrubs or trees
  • Members of the Crataegus (Hawthorn) genus: shrubs or trees
  • Members of the Geum (Avens) genus: herbaceous plants
  • Members of the Potentilla (Cinquefoil) genus: herbaceous plants
  • Members of the Prunus (Cherry) genus: shrubs or trees
  • Members of the Rosa (Rose) genus: shrubs
  • Members of the Spiraea genus (Meadowsweet) genus: shrubs
Shrub of Saskatoon serviceberry (Amelanchier alnifolia) in a garden.
Saskatoon Serviceberry (Amelanchier sanguinea) — Daderot, CC0, via Wikimedia Commons

Western Tiger Swallowtail (Papilio rutulus) and its host plants in Spokane, Washington

Orange caterpillar of western tiger swallowtail (Papilio rutulus) on tree.
Orange Caterpillar of Western Tiger Swallowtail — Cslucas, CC BY-SA 4.0, via Wikimedia Commons
Green caterpillar of western tiger swallowtail (Papilio rutulus).
Green Caterpillar of Western Tiger Swallowtail — Tsu Dho Nimh, CC BY-SA 4.0, via Wikimedia Commons
Adult western tiger swallowtail (Papilio rutulus) on willow.
Western Tiger Swallowtail (Papilo rutulus) — Calibas at en.wikipedia, Public domain, via Wikimedia Commons

Western Tiger Swallowtail (Papilio rutulus)

The western tiger swallowtail flies in the western United States and northern Mexico. The green eggs are laid on the host plants. The caterpillar when it first comes out resembles a bird dropping but then becomes orange and then green with age. The chrysalis looks like wood to camouflage it.

The adults have a wingspan of 3 in (7.6 cm) to 4 in (10.1 cm) and are yellow with black stripes. Generally there are one to two broods a year.

Plants that Host the Western Tiger Swallowtail

The western tiger swallowtail, like its eastern counterpart, is a generalist and feeds on numerous shrubs and trees. Some species that host this swallowtail in the Spokane area include:

  • Speckled Alder (Alnus incana): a shrub to tree
  • Red Alder (Alnus rubra): a tree
  • Water Birch (Betula occidentalis): a shrub or tree
  • Paper Birch (Betula papyrifera): a tree
  • Cultivated Apple (Malus pumila): an introduced tree
  • Members of the Prunus (Cherry) genus: shrubs or trees
  • Quaking Aspen (Populus tremuloides): a tree
  • Arroyo Willow (Salix lasiolepis): a shrub or tree
Tree of paper birch (Betula papyrifera).
Paper Birch (Betula papyrifera) — Laval University, CC BY-SA 4.0, via Wikimedia Commons
Autumn foliage on quaking aspen (Populus tremuloides).
Quaking Aspen (Populus tremuloides) — Satsuuma, Public domain, via Wikimedia Commons

Anise Swallowtail (Papilo zelicaon) and its host plants in Spokane, Washington

Green and black caterpillar of anise swallowtail (Papilio zelicaon) on leaf.
Green and Black Caterpillar of Anise Swallowtail — Bento00, Public domain, via Wikimedia Commons
Adult anise swallowtail (Papilio zelicaon) on yellow willow flower.
Anise Swallowtail (Papilio zelicaon) — ALAN SCHMIERER, CC0, via Wikimedia Commons
Female anise swallowtail (Papilio zelicaon) on ground.
Female Anise Swallowtail (Papilio zelicaon) — Eugene Zelenko, CC BY-SA 4.0, via Wikimedia Commons

Anise Swallowtail (Papilio zelicaon)

The anise swallowtail flies in the western United States.

The greenish eggs are laid on the leaves of the host plant. The caterpillars are dark brown in the first two instars but become more green ending with a green, black, and yellow color. The chrysalis has the appearance of a branch (Wikipedia – Papilio zelicaon) of the host plant and is light green to brown (butterfly identification).

The adults have a wingspan of 2 in (5 cm) to 3 in (7.6 cm) and are black and yellow with blue on the hindquarters and a red eyespot on the bottom middle. This species looks like the eastern tiger swallowtail without the vertical stripes and is smaller (butterfly identification).

Plants that Host the Anise Swallowtail

The anise swallowtail utilizes members of the carrot family (Apiaceae) as host plants. Some examples in the Spokane, WA area incude:

  • Lyall’s Angelica (Angelica arguta): a herbaceous plant
  • Western Water Hemlock (Cicuta douglasii): a herbaceous plant
  • American Cow-Parsnip (Heracleum maximum): a herbaceous plant
  • Members of the Lomatium genus
  • Mountain Sweet-Cicely (Osmorhiza berteroi)
White flowers of western water hemlock (Cicuta douglasii) on a black background.
Flowers of Western Water Hemlock (Cicuta douglasii) — Public Domain from Wikimedia Commons
White flowers of american cow parsnip (Heracleum maximum).
American cow-parsnip (Heracleum maximum) — Patrick Alexander from Las Cruces, NM, CC0, via Wikimedia Commons

Clodius Parnassian (Parnassius clodius) and its host plants in Spokane, Washington

Clodius parnassian (Parnassius clodius) on a white flower.
Clodius Parnassian (Parnassius clodius) — ALAN SCHMIERER from southeast AZ, USA, CC0, via Wikimedia Commons
Clodius parnassian (Parnassius
Clodius Parnassian (Clodius parnassius) — U.S. Forest Service- Pacific Northwest Region, Public domain, via Wikimedia Commons

Clodius Parnassian (Parnassius clodius)

The clodius parnassian flies in the western United States and southwestern Canada. This is the only parnassian butterfly that is restricted entirely to North America (Pyle 1981).

The turban shaped eggs (Elrod and Maley 1906) are laid on or near the host plants and emerge the next year (McCorkle and Hammond 1985). The caterpillars are of two colorations depending on habitat. In alpine areas they are gray-brown, to blend with rocks, or black with yellow spots in rain-forests (McCorkle and Hammond 1985). The black and yellow variant mimics the color of a millipede that is distasteful (McCorkle and Hammond 1985). The caterpillar then pupates in dark brown cocoon a few weeks to emerge in the late spring or summer as an adult.

The adults have a wingspan of 2.25 in (5.7 cm) to 3.0 in (7.6 cm) and are white colored with black checkered marks and scattered red spots.

Plants that Host the Clodius Parnassian

The clodius parnassian uses members of the Dicentra and Corydalis genera as host plants (McCorkle and Hammond 1985). Some members of these genera in the Spokane area that host this species include (McCorkle and Hammond 1985):

  • Long-Horn Steer’s Head (Dicentra uniflora): a herbaceous plant
  • Dutchman’s-Breeches (Dicentra cucullaria): a herbaceous plant
  • Scrambledeggs (Corydalis aurea): a herbaceous plant
Yellow flowers of scrambledeggs (Corydalis aurea) in an open area.
Scrambledeggs (Corydalis aurea) — Patrick Alexander from Las Cruces, NM, CC0, via Wikimedia Commons
Plant of long horn steers head (Dicentra uniflora) in a shaded area.
Long-horn Steers Head (Dicentra uniflora) — Alan Rockefeller, CC BY-SA 4.0, via Wikimedia Commons

Rocky Mountain Parnassian (Parnassius smintheus) and its host plants in Spokane, Washington

Rocky Mountain Parnassian (Parnassius smintheus) with wings folded.
Rocky Mountain Parnassian (Parnassius smintheus) — ALAN SCHMIERER, CC0, via Wikimedia Commons
Rocky Mountain parnassian (Parnassius smintheus) with wings outspred on the ground.
Rocky Mountain Parnassian (Parnassius smintheus) — ALAN SCHMIERER, CC0, via Wikimedia Commons

Rocky Mountain Parnassian (Parnassius smintheus)

The Rocky Mountain parnassian flies in western North America except for the the extreme southwest. The white eggs are laid nearby to the host plants and they overwinter as eggs. The caterpillar is black at first but then develops a row of yellow spots (Miller and Hammond 2003). The pupa are brownish in color

The adult is ranges in color from white to yellow-brown and is accented by red and black spots. The wingspan is about 2 in (5.1 cm) to 3 in (7.6 cm). The adults fly during the summer (from about July to September).

Plants that Host the Rocky Mountain Parnassian

The Rocky Mountain parnassian utilizes plants in the Sedum and Saxifraga genera (Elrod and Maley 1906). Some species in these genera in the Spokane area include:

  • Spearleaf Stonecrop (Sedum lanceolatum): a herbaceous plant
  • Matted Saxifrage (Saxifraga austromontana): a herbaceous plant
Plants of lance-leaf stonecrop (Sedum lanceolatum) in rocks.
Lance-leaf Stonecrop (Sedum lanceolatum) — Patrick Alexander from Las Cruces, NM, CC0, via Wikimedia Commons
Plants of matted saxifrage (Saxifraga ausromontana) on a black background.
Matted Saxifrage (Saxifraga austromontana) — RG Johnsson, Public domain, via Wikimedia Commons

Nectar Plants to Consider Putting in Your Garden

Pinkish-white flowers of showy milkweed (Asclepias speciosa).
Flowers of Showy Milkweed — Asclepias speciosa Torr. observed in Canada by markeambard (licensed under CC0 1.0)

While the swallowtails need certain species of plants to use as hosts, the adults also need nectar plants to visit in order to get nourishment. Nectar plants can also help other insects such as bees and no garden is complete without nectar plants. Some common nectar plants that can be grown in the Spokane, WA area include:

  • Ragworts (Senecio spp.): a genus of herbaceous plants (Shields 1972)
  • Goldenrods (Solidago spp.): a genus of herbaceous plants
  • Milkweeds (Asclepias spp.) — Also benefit the Monarch Butterfly (Danaus plexippus): a genus of herbaceous plants
  • Asters (Symphyotrichum spp.): a genus of herbaceous plants
  • Black-eyed Susan (Rudbeckia hirta): a herbaceous plant
  • Northern Mule’s-Ears (Wyethia amplexicaulis): a herbaceous plant (Shields 1972)

Frequently Asked Questions

How much land do I need to start a butterfly garden?

Every plant that you can grow can make a difference for visitors to your garden, especially in urban areas. Potted plants are also useful en masse for pollinators. When planting your garden, make sure you plant both the host plants and nectar plants for the adults to feed on.

Where should I get my plants?

For pollinators, it is best to have native plant species. The insects will be used to these plants more than ones from other places. Be sure you get your plants from a reputable nursery does not use neocontinids that would harm visitors to your garden.

Are there gardens near me, where I can see an example of a butterfly garden?

There are two gardens in the Spokane, WA area that can be visited in order to get ideas for your Butterfly Garden. These include:

John A. Finch Arboretum: an arboretum that contains a natural area with plants native to the area.

Manito Park: a park that has a number of gardens that can be visited.

Books where you can find out more about Butterfly Gardening in the Spokane, WA Area

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References

  • Elrod, Morton J. and Frances Inez Maley. 1906. The butterflies of Montana: with keys for determination of species. (Missoula, MT: University of Montana). Bulletin no. 30, series 10.
  • McCorkle, David V. and Paul C. Hammond. 1985. Observations on the Biology of Parnassius clodius (Papilionidae) in the Pacific Northwest. Journal of the Lepidopterists’ Society 39(3): 156-162.
  • Miller, J.C. and Paul C. Hammond. 2003. Lepidoptera of the Pacific Northwest: caterpillars and adults. USDA Forest Service Series 2003-03.
  • Pyle, Robert Michael. 1981. National Audubon Society Field Guide to North American Butterflies. (New York: Alfred A. Knopf).
  • Shields, O. 1972. Flower visitation records for butterflies (Lepidoptera). Pan-Pacific Entomologist 48: 189-203.
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Robert Coxe

Robert Coxe

Robert Coxe is a professional ecologist and botanist who has worked as the State Ecologist of Delaware and as an ecologist for the Western Pennsylvania Conservancy. He is also a former Past-President of the Pennsylvania Academy of Science. He currently is an innkeeper at McMullen House Bed & Breakfast LLC and a web designer and owner for Silphium Design LLC.

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