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
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
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
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.
Giant Swallowtail (Papilo cresphontes) and its host plants in San Diego, California
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.
Pale Swallowtail (Papilio eurymedon) and its host plants in San Diego, California
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
Indra Swallowtail (Papilio indra) and its host plants in San Diego, California
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
Two-tailed Swallowtail (Papilio multicaudata) and its host plants in San Diego, California
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
Black Swallowtail (Papilio polyxenes) and its host plants in San Diego, California
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
Western Giant Swallowtail (Papilio rumiko) and its host plants in San Diego, California
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
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
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
Anise Swallowtail (Papilo zelicaon) and its host plants in San Diego, California
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
Nectar Plants to Consider Putting in Your Garden
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
- Daniels, Jaret C. 2023. Garden Bugs & Insects of California: Identify Pollinators, Pests, and Other Garden Visitors – Adventure Quick Guides. Adventure Publications. 36 pp.
- Hall, Clarence A. 2007. Introduction to the Geology of Southern California and Its Native Plants. University of California Press. 493 pp.
- Keator, Glenn and Alrie Middlebrook. 2007. Designing California Native Gardens: The Plant Community Approach to Artful, Ecological Gardens. University of California Press. 366 pp.
- Lowry, Judith Larner. 2007. The Landscaping Ideas of Jays: A Natural History of the Backyard Restoration Garden. University of California Press. 316 pp.
- Miller, George Oxford. 2022. Native Plant Gardening for Birds, Bees & Butterflies. Southern California – Nature Friendly Gardens. Adventure Publications. 276 pp.
- Schmidt, Marjorie G., Katherine L. Greenberg, and Beth D. Merrick. 2012. Growing California Native Plants. University of California Press. 296 pp.
- Smith, Nevin M. 2006. Native Treasures: Gardening with the Plants of California. University of California Press. 272 pp.
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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.
