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An Easy Butterfly Gardener’s Guide to San Diego, CA Swallowtails and their Host Plants

Table of Contents for Swallowtail Butterflies and Host Plants in San Diego, CA

San Diego, California is located in southwestern California in the County of San Diego and has two plant hardiness zones. Along the coast is zone 10, while farther inland to the east is zone 9. San Diego has nine species of Swallowtail butterflies that you can host in your butterfly garden.

Location of the San Diego, CA Area

Map of the state of California with San Diego County highlighted.
Map of California showing San Diego County — David Benbennick, Public domain, via Wikimedia Commons

San Diego, California is located within San Diego County in southwestern California. This blog post covers the entire county as the San Diego area.

USDA Plant Hardiness Zones in San Diego, California

Map of the USDA plant hardiness zones for southern California.
Map of USDA Plant Hardiness Zones for Southern California –USDA Public Domain

The San Diego, CA area is located in zone 10 along the coast and zone 9 in the east. When selecting plants you will want to get those that can handle temperatures as cold as +30F if you are near the coast and +20 if you are inland (east) to be sure they will survive.

Pipevine Swallowtail (Battus philenor) and its host plants in San Diego, California

Eggs of pipevine swallowtail (Battus philenor) on a plant.
Eggs of Pipevine Swallowtail — Insects Unlocked, CC0, via Wikimedia Commons
Caterpillar of the pipevine swallowtail (Battus philenor) on the ground.
Caterpillar of Pipevine Swallowtail — Insects Unlocked, CC0, via Wikimedia Commons
Pipevine Swallowtail (Battus philenor) on a yellow goldenrod plant.
Pipevine Swallowtail (Battus philenor) — ALAN SCHMIERER, CC0, Wikimedia Commons
Brown chrysalis of pipevine swallowtail (Battus philenor) on a twig.
Brown chrysalis of pipevine swallowtail — Meganmccarty, Public domain, via Wikimedia Commons

Pipevine Swallowtail (Battus philenor)

The pipevine swallowtail flies throughout the United States, except for the Pacific Northwest. It has orange-brown eggs that are laid on the host plant. The black to brown to red caterpillar with orange markings comes out in the spring. They then overwinter as a pupa (Monroe and Wright 2017).

In the spring and into the summer the adult butterflies start to fly. They have a wingspan of 2.5 inches (6.4 cm) to 5 inches (12.7 cm) inches and are black colored with white markings. In California, this species has two flights, one in the spring and one in the mid-summer (Sims and Shapiro 1982).

Plants that Host the Pipevine Swallowtail

The pipevine swallowtail is generally hosted by members of the birthwort family (Aristolochiaceae). In San Diego, CA, the California Pipevine (Isotrema californica) hosts this species.

Greenish-yellow flower of California pipevine (Isotrema californica).
Flower of California Pipevine (Isotrema californica) — No machine-readable author provided. Curtis Clark assumed (based on copyright claims)., CC BY-SA 2.5, via Wikimedia Commons

Giant Swallowtail (Papilo cresphontes) and its host plants in San Diego, California

Yellow of egg of giant swallowtail (Papilio cresphontes) on a green leaf.
Egg of Giant Swallowtail — Anne Toal from US, CC BY 2.0, via Wikimedia Commons
Brownish-black caterpillar of giant swallowtail (Papilio cresphontes) on a leaf.
Caterpillar of Giant Swallowtail — Aaron Carlson from Menomonie, WI, USA, CC BY-SA 2.0, via Wkimedia Commons
Brown chrysalis of giant swallowtail (Papilio cresphontes) attached to a leaf.
Brown chrysalis of Giant Swallowtail — Ianaré Sévi, CC BY-SA 3.0, via Wikimedia Commons
Adult of giant swallowtail (Papilio cresphontes) butterfly on vegetation.
Giant Swallowtail (Papilio cresphontes) — ALAN SCHMIERER, CC0, via Wkimedia Commons

Giant Swallowtail (Papilio cresphontes)

The giant swallowtail flies throughout the United States and southeast Canada, except for the northwest. Beyond North America it ranges into Central America and the Caribbean Islands. It is the largest butterfly in North America (Wikipedia – Papilio cresphontes).

Giant swallowtail has brownish-orange eggs that are laid on the host plants. The caterpillars have five stages or instars before pupating, which takes about two weeks. The chrysalis resembles dead wood (West and Hazel 1996).

The adult butterflies have a wingspans ranging from about 5.5 inches (14 cm) to 7.5 inches (19 cm) and are black and yellow colored. They fly during June in San Diego (Brown and Bash 2000).

Plants that Host the Giant Swallowtail

The giant swallowtail is hosted by members of the Rutaceae, of which there is one species in the San Diego area, common rue (Ruta graveolens), an introduced herbaceous plant. Presumably, California hoptree (Ptelea crenulata) is also a host, but this could not be confirmed in the literature.

Common rue (Ruta graveolens) in a garden.
Common Rue (Ruta graveolens) — Daderot, Public domain, via Wikimedia Commons

Pale Swallowtail (Papilio eurymedon) and its host plants in San Diego, California

Green caterpillar of pale swallowtail (Papilio eurymedon) on a leaf.
Papilio eurymedon Lucas, 1852 observed in United States of America by Dee Shea Himes (licensed under CC BY 4.0)
Brown caterpillar of pale swallowtail (Papilio eurymedon) on leaf.
Brown Caterpillar — Papilio eurymedon Lucas, 1852 observed in United States of America by Yann Kemper (licensed under CC0 1.0).
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 like bark to camouflage it (Wikipedia – Papilio eurymedon).

The black and cream colored adults have a wingspan of 3.5 inches (8.9 cm) to 4.5 inches (11.4 cm) and fly from April to October and have up to two broods especially along the coast.

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 in the San Diego that host this species include:

  • Mountain Whitethorn (Ceanothus cordulatus): a shrub
  • Wedgeleaf Buckbrush (Ceanothus cuneatus): a shrub
  • Deerbrush (Ceanothus integerrimus): a shrub
  • California False-Buckthorn (Frangula californica): a shrub or tree
  • Creambush (Holodiscus discolor): a shrub
  • Holly-leaf Cherry (Prunus ilicifolia): a shrub or tree
  • Holly-leaf Buckthorn (Rhamnus crocea): a shrub or tree
White flowers of holly leaf cherry (Prunus ilicifolia).
Flowers of Holly-leaf Cherry — Prunus ilicifolia (Nutt. ex Hook. & Arn.) D.Dietr. observed in United States of America by George Williams (licensed under CC BY 4.0)

Indra Swallowtail (Papilio indra) and its host plants in San Diego, California

Black caterpillar of indra swallowtail (Papilio indra).
Papilio indra subsp. minori Cross, 1937 observed in United States of America by Robb Hannawacker (licensed under CC0 1.0)
Pink caterpillar of indra swallowtail (Papilio indra). on vegetation.
Pink Caterpillar — Papilio indra subsp. minori Cross, 1937 observed in United States of America by Robb Hannawacker (licensed under CC0 1.0)
Adult of indra swallowtail (Papilio indra) on surface.
Adult of Indra Swallowtail — Papilio indra subsp. minori Cross, 1937 observed in United States of America by Robb Hannawacker (licensed under CC0 1.0)

Indra Swallowtail (Papilio indra)

The Indra swallowtail flies in the western United States. The whitish-colored eggs are laid on the leaves of the host plant. The caterpillars have two color variations, first black and then the last stage is pink with black striping. The caterpillars go through five instars. It hibernates during the winter as a chrysalis.

The black and cream colored adults with two orange eyespots at the bottom have a wingspan of 2.5 inches (6.4 cm) to 3 inches (7.6 cm) and fly from March to July in a single brood.

Plants that Host the Indra Swallowtail

The indra swallowtail uses members of the carrot family (Apiaceae). Some plants in the San Diego that host this species include:

  • Desert Spring Parsley (Cymopterus deserticola): a herbaceous plant
  • Panamint Spring-Parsley (Cymopterus panamintensis): a herbaceous plant
  • Members of the Lomatium (Desert-Parsley) genus: herbaceous plants
  • Members of the Tauschia (Umbrella-wort) genus: herbaceous plants
Leaf of California desert-parsley (Lomatium californicum).
Leaves of California Desert-parsley (Lomatium californicum) — Robert Steers/NPS, CC0, via Wikimedia Commons

Two-tailed Swallowtail (Papilio multicaudata) and its host plants in San Diego, California

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 swallowtail 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.

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

Plants that Host the Two-tailed Swallowtail

The two-tailed swallowtail utilizes members of the Rue Family (Rutaceae) and the Rose Family (Rosaceae). Some species in the San Diego area include:

  • Members of the Prunus genus (Cherries, Peach, and Almond): shrubs to trees
  • California hoptree (Ptelea crenulata): a shrub to tree
  • Common Rue (Ruta graveolens): an introduced herb
Common rue (Ruta graveolens) in a garden.
Common Rue (Ruta graveolens) — Daderot, Public domain, via Wikimedia Commons
Flowers and leaves of california hoptree (Ptelea crenulata).
California Hoptree (Ptelea crenulata) — Anthony Baniaga, CC0, via Wikimedia Commons

Black Swallowtail (Papilio polyxenes) and its host plants in San Diego, California

Black and white caterpillar of black swallowtail (Papilio polyxenes) on vegetation.
Black and White Caterpillar of Black Swallowtail — Inklet Arts, CC BY 2.0, via Wikimedia Commons
Green and yellow caterpillar of black swallowtail (Papilio polyxenes).
Caterpillar of Black Swallowtail — NCBioTeacher, CC0, via Wikimedia Commons
Greenish-brown chrysalis of black swallowtail (Papilio polyxenes).
Chrysalis of Black Swallowtail — Photo by and (c)2009 Derek Ramsey (Ram-Man), GFDL 1.2, via Wikimedia Commons
Black swallowtail (Papilio polyxenes) on fence.
Black Swallowtail (Papilio polyxenes) — Kaldari, CC0, via Wikimedia Commons

Black Swallowtail (Papilio polyxenes)

The black swallowtail flies in most of the United States, except for the Northwest. The yellow eggs are laid on the host plants and take about a week to hatch. The caterpillars are at first black colored but later have green, black, and yellow coloring and last from a week to a month. The butterflies then survive the winter as a chrysalis.

The adults have a wingspan of 2.5 (7cm) to 3.5 inches (8.5cm) and are black colored with yellow spots along the wings and a red eyepsot near the tail on the top. The underside has orange spots.

Plants that Host the Black Swallowtail

The black swallowtail is a generalist and uses members of the carrot family (Apiaceae) as host plants. Some examples of carrot family members in San Diego include:

  • Cut-leaf Water-Parsnip (Berula erecta): a herbaceous plant
  • Spotted Water Hemlock (Cicuta maculata): a herbaceous plant
  • California Eryngo (Eryngium aristulatum): a herbaceous plant
  • Fennel (Foeniculum vulgare): an introduced herbaceous plant
Plant of california eryngo (Eryngium aristulatum).
California Eryngo (Eryngium aristulatum) — Pacific Southwest Region USFWS from Sacramento, US, Public domain, via Wikimedia Commons
Yellow flowers of sweet fennel (Foeniculum vulgare).
Flowers of Sweet Fennel (Foeniculum vulgare) — Javier martin, Public domain, via Wikimedia Commons

Western Giant Swallowtail (Papilio rumiko) and its host plants in San Diego, California

Orange egg of western giant swallowtail (Papilio rumiko) on leaf.
Egg of Western Giant Swallowtail — Jengod, CC BY-SA 4.0, via Wikimedia Commons
Brown caterpillar of western giant swallowtail (Papilio rumiko) on leaf.
Brown Caterpillar of Western Giant Swallowtail — Karthik Praveen, CC BY-SA 4.0, via Wikimedia Commons
Western giant swallowtail (Papilio rumiko) on orange flower.
Western Giant Swallowtail (Papilio rumiko) — ALAN SCHMIERER, CC0, via Wikimedia Commons
Ventral view of the western giant swallowtail (Papilio rumiko) on white background.
Ventral view of Western Giant Swallowtail — Kojiro Shiraiwa, Qian Cong, Nick V. Grishin, CC BY 4.0, via Wikimedia Commons

Western Giant Swallowtail (Papilio rumiko)

The western giant swallowtail is common the Arctic regions and in Europe and North America. In North America it flies from the midwest and western United States, western Canada, and Alaska. The orange-brown eggs are laid on the young leaves and shoots of the host plants (Shiraiwa, et al 2014). The brownish caterpillar has five instars and appears as a bird dropping. The chrysalis is matches the color of the branch it is attached to, either gray or brown.

The adult is black and yellow on the top and mostly yellow on the bottom (see images). The wingspan is about 3.9 inches (9.9 cm) to 4.5 inches (11.4 cm). The adults fly from February to mid-November in the San Diego area.

Plants that Host the Western Giant Swallowtail

The western giant swallowtail uses plants in the Rue Family (Rutaceae) as host plants. In the San Diego area, these include:

  • Bush-rue (Cneoridium dumosum): a shrub
  • California hoptree (Ptelea crenulata): a shrub to tree
  • Common Rue (Ruta graveolens): an introduced herbaceous plant
  • Turpentine-Broom (Thamnosma montana): a shrub
Flowers and leaves of california hoptree (Ptelea crenulata).
California Hoptree (Ptelea crenulata) — Anthony Baniaga, CC0, via Wikimedia Commons
Plant of turpentine-broom (Thamnosma montana) in a desert.
Turpentine Broom (Thamnosma montana) — Patrick Alexander from Las Cruces, NM, CC0, via Wikimedia Commons

This species can also be found on Citrus trees in gardens (Shiraiwa, et al 2014).

Western Tiger Swallowtail (Papilio rutulus) and its host plants in San Diego, California

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. This butterfly is the eastern counterpart to the eastern tiger swallowtail (Papilio glaucus), which is in the eastern United States.

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, similar to the eastern tiger swallowtail. 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 in the San Diego area include:

  • Speckled Alder (Alnus incana): a shrub to tree
  • Oregon Ash (Fraxinus latifolia): a tree
  • Velvet Ash (Fraxinus velutina): a tree
  • Cultivated Apple (Malus pumila): an introduced tree
  • California Sycamore (Platanus racemosa): a tree
  • Holly-leaf Cherry (Prunus ilicifolia): a shrub to tree
  • Cottonwood (Populus deltoides): a tree
  • Black Poplar (Populus nigra): an introduced tree
  • Quaking Aspen (Populus tremuloides): a tree
Autumn foliage on quaking aspen (Populus tremuloides).
Quaking Aspen (Populus tremuloides) — Satsuuma, Public domain, via Wikimedia Commons
White flowers of holly leaf cherry (Prunus ilicifolia).
Prunus ilicifolia (Nutt. ex Hook. & Arn.) D.Dietr. observed in United States of America by George Williams (licensed under CC BY 4.0)

Anise Swallowtail (Papilo zelicaon) and its host plants in San Diego, California

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 San Diego area incude:

  • Woolly Angelica (Angelica tomentosa): a herbaceous plant
  • Spotted Water Hemlock (Cicuta maculata): a herbaceous plant
  • American Wild Carrot (Daucus pusillus): a herbaceous plant
  • Sweet Fennel (Foeniculum vulgare): a introduced herbaceous plant
  • Members of the (Lomatium) Desert-Parsley genus: herbaceous plants
White flowers of woolly angelica (Angelica tomentosa).
Flowers of Woolly Angelica (Angelica tomentosa) — Morgan Stickrod, CC BY-SA 4.0, via Wikimedia Commons
White flowers of american wild carrot (Daucus pusillus).
Flowers of American Wild Carrot (Daucus pusillus) — Stickpen, Public domain, via Wikimedia Commons

Nectar Plants to Consider Putting in Your Garden

Pinkish-white and hairy flowers of California milkweed (Asclepias californica).
Flowers of California Milkweed (Asclepias californica) — Joe Decruyenaere, CC BY-SA 2.0, via Wikimedia Commons

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 San Diego, CA area include:

  • 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

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 several gardens in the San Diego area that can be visited in order to get ideas for your Butterfly Garden. These include the:

Alta Vista Botanical Garden: has a California Native Plant Garden.

Balboa Park: a park with a butterfly garden.

Palomar College Arboretum: has a native plant garden and butterfly/bird garden.

Point Loma Native Plant Garden: a native plant garden showing native plants along the San Diego River.

San Diego Botanic Garden: contains a native plant garden.

San Diego Zoo: A zoo with a variety of gardens with plants from around the world.

San Dieguito County Park: has a butterfly garden in the park.

Water Conservation Garden: has a native plant garden and buttefly pavillion.

Books where you can find out more about Butterfly Gardening in the San Diego, CA Area

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References

  • Brown, John W. and Katherine Bash. 2000. The Lepidoptera of Marine Corps Air Station Miramar: Calculating faunal similarity among sampling sites and estimating total species richness. Journal of Research on the Lepidoptera 36: 45-78.
  • Shiraiwa, Kojiro, Qian Cong, and Nick V. Grishin. 2014. A new Heraclides swallowtail (Lepidoptera, Papilionidae) from North American recognized by the pattern on its neck. Zookeys 468: 85-135.
  • Sims, S.R. and A.M. Shapiro. 1982. Seasonal Phenology of Battus philenor (L.) (Papilionidae) in California. Journal of the Lepidopterists’ Society 37(4): 281-288.
  • West, David A. and Wade N. Hazel. 1996. Natural Pupation sites of three North American swallowtail butterflies: Eurytides marcellus (Cramer), Papilio cresphontes Cramer, and P. troilus L. (Papilionidae). Journal of the Lepidopterists’ Society 50: 297-302.
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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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