Butterflies (So CA focus) and How to Attract Them

Butterflies (So CA focus) and How to Attract Them

It’s a rare person who doesn’t get excited when a butterfly flits by. Lately we’ve had a lot of Western Tiger Swallowtails flying around our property, which makes sense because we have the host plant  — sycamore — that it needs to lay its eggs and for its caterpillar stage. Plus we have plenty of buckwheat and yarrow all summer long that provide nectar for local butterflies.

Today I attended a talk “Butterflies of the Los Angeles Basinat Rancho Santa Ana Botanic Garden in Claremont, a native plant haven that I love to visit to see all types of critters in their native habitat.

Clark Thompson, a well-known butterfly expert and photographer in the region, introduced us to butterfly biology and to the main butterflies in the area. The talk was 2 hrs so here are my highlights, along with photos from the class and the RSABG’s butterfly exhibit (a great exhibit every year – but only open til July 29)

My takeaways:

  • Numbers: For perspective, of 800 different butterfly species in North America, we have 300 in California -175 in Southern CA. There are 20,000 species worldwide, with new ones being discovered in tropical areas. (Moths species – a whopping 10 times more.)
  • Plant requirements: To survive, butterflies need both their host plants for their early stages (egg laying, larva or caterpillar, and pupa (chrysalis) stage) and their nectar plants when butterflies. Most share a variety of nectar plants  but may only have one host plant, usually natives or their hybrids- another reason to plant natives. Our landscaping with natives (see prior posts, such as butterfly/bird landscaping for the Midwest/East and California/Southwest),  has led to many more butterflies and fascinating insects, lizards and lately even California pocket mice.
  • Great nectar plants: yarrows, buckwheats, daisies, asters, sage (salvia), mallow, ceanothus
  • Where to find butterflies:  From our experience, plant natives!  But if you don’t have any butterflies on your property, Thompson said to head to areas (canyons in So CA) with some water, which also have some shade and some flowers for nectar —  and you’ll likely find them March through July.  In the LA Basin – San Gabriel Canyon, Eaton Canyon by Pasadena, Glendora Ridge Road, San Antonio Canyons, and Barton Flats up in the San Bernardino Mountains.
  • In the caterpillar stage, the butterfly will usually go through 4 stages called instars, shedding and getting larger each time. Many look completely different in the later stages, for example, the Western Tiger Swallowtail is black and white in the earlier stage to look like bird poop, but becomes green in the 3rd instar to match the sycamore or willow leaf.
  • In the fall months in So. CA we may see the Purple Hairstreaks (host plant – the mistletoe in sycamore – mistletoe) and Lorquin’s Admirals (willows). Some butterflies have a second brood depending on conditions.

Local (LA Basin) Butterflies (with host plant in parentheses):

  • Western Tiger Swallowtail (host plant: Sycamore or willow)
  • Pale Swallowtail (ceanothus, coffeeberry – both plants we have a lot of in our landscaping)
  • Anise Swallowtail (fennel and carrot family plants)
  • Pipevine Swallowtail (Dutchman’s Pipevine)
  • Orange-tips ( mustard)
  • California Dogface (false indigo, found in the San Gabriel and San Bernardino mountains
  • Cabbage White (nasturtium and mustard family)
  • Cloudless Sulfur (Senna or cassia)
  • West Coast Lady (mallow)
  • Red Admiral (stinging nettle)
  • Painted Lady has numerous host plants, why they’re so plentiful
  • Mourning Cloak (Chinese Elm)
  • Cabbage white are introduced from Europe, along with its host plant (mustard)
  • Variable Checkerspot (figwort, monkeyflower)
  • Monarch (milkweed) – see below concern about milkweed

My photos (mostly Monarch butterfly and Pipevine Swallowtail stages):

If you’re wondering where all the butterflies have gone…. one area of concern: I plan to write more about this but researchers  have found that the rapid spread of herbicide-resistant crops (GMO crops) has coincided with—and may explain—the decline in monarch butterflies over the past decade. Published in Insect Conservation and Diversity, John Pleasants, a monarch researcher at Iowa State University, and Karen Oberhauser of the University of Minnesota estimated that the number of monarch eggs declined by 81 percent across the Midwest between 1999 and 2010. During this period, milkweed plants— which host the eggs and caterpillars produced by monarch butterflies— nearly disappeared from corn and soybean fields. The reason this is important:  monarch butterflies generally lay nearly four times as many eggs on farm field plants as on those in pastures or on roadsides.

Also, and this is important: Pesticide kills beneficial insects, including the butterfly caterpillars. Try to avoid pesticide use.

For more info:

Clark Thompson’s website InsectNet.com (butterfly collecting, photo galleries, discussion forums)

Rancho Santa Ana Botanic Garden – www.rsabg.org

Native Plants for Western Butterfly Gardens – Las Pilitas website article – Google for local butterfly attracting plants in your area.


About Linda Richards

My goal is to educate about the science of nature in layperson speak, through my writing, science and education background. I grew up in the Chicago area, loved living in Minneapolis before gravitating to the West, which is now home.


  1. Jeffrey Caldwell says:

    The one with caption “Pipevine Swallowtail butterfly” [5521] is actually a Mourning Cloak.

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