Soapplant in the Native Garden, by Bill Hunt

Sub-title: An experience you may not get from seeing native plants in the wild!


We re-did our back yard landscaping in winter of 2011-2012. We expected to have a few sparse years but apparently our soil contained plenty of California poppy seed waiting for the opportunity that expanses of bare ground provided them.  We’ve had two springs of saturated orange color from the thousands of poppies but we have other plants to enjoy as well.

After the landscaping was done, my wife Lesley planted a dozen soap plant, Chlorogalum pomeridianum. The first spring, most survived and one plant produced flowers. This year, four of the soap plants bloomed. The leaves of the soap plant don’t get far above the ground so when the plant begins to produce a four to six foot tall stalk, it is a very dramatic announcement of things to come.  When the flowers appear, they are worth the wait.

Every evening starting in mid-May, a few blossoms open.  The flowers begin to open around 5:30-6pm. and are fully open by the time twilight fades into night.  The flowers have begun to wilt before we get up in the morning.  Producing flowers that only last through one night seems a chancy survival strategy, but it seems to work for this plant.  In our Walnut Creek Open Space, soap plants hold their own in grasslands dominated by alien oats and rye.

The flower buds are elongated striped ovals like small beans. The soap plant flowers are fairly small and mostly white but they have a very elegant design.  From a distance, the flowers look like feathers in the soft evening light.  Up close, the curve of the petals, the shape of the flower parts and the color of the stamens are striking.  Captured in a picture with a closeup lens, the flowers will give pleasure for years to come.

If I want to see this show, I have to be out watching the plants as the light fades.  That’s hard to do in park and open space areas that are closed to visitors at night.  Having the plants blooming in our backyard lets me enjoy the blooming process at length night after night.  One evening, I was able to watch a flower bud as it opened over 4 minutes.

Bud opening!

Click to watch Bud opening!
Chlorogalum pomeridianum, Soapplant

I love taking pictures of flowers so this year I spent several evenings trying to get good pictures.  There is not much light at the end of the day so shutter speeds are very slow.  Since there is usually a breeze at that time of day, I get lots of blurry pictures.  Sometimes the breeze blows the flower completely out of the frame and I get a picture with no flower at all.  If I remembered to get outside early, took plenty of pictures and had good luck, I’ll have some keepers when the light gets too dim for pictures.

I have wondered what sort of pollinators would visit the flowers during the night.  Some people suggested moths or bats as the pollinators.  I never saw either of those but I have seen yellow-faced bumblebees coming for a nightcap before the light faded completely.

The plants were finished blooming by the beginning of June but there are lots of seed pods growing on the plants now.  We’ll have more plants and a bigger show in a few years.

Bill Hunt is the Chapter Council representative of the East Bay Chapter and a board member of the California Native Plant Society.

2 thoughts on “Soapplant in the Native Garden, by Bill Hunt

  1. I have observed plenty of bumblebee visits to soap root flowers in some contexts, and bumblebees coming immediately to flowers as they popped open.

    Soap root flowers attract hawkmoths, according to the California Horticultural Society. Lepidopterist Greg Kareofelas sees the White-lined Sphinx (Hyles lineata) moth at nectar on it. Many Sequoia Sphinx (Sphinx sequoiae) seen visiting its flowers near Mather in the Sierra Nevada. Moldenke in a flower visitation study captured 10 species of unidentified nocturnal moths at its flowers.

    The white flowers audibly pop open in late afternoon, often getting immediate attention from bumblebees. A pollination ecology field study concluded its prime pollinators are various bees, not moths, as some had guessed. May – August.

    Soap Lily is a major larval host for the Brown Elfin butterfly in the San Francisco Bay Region (Arthur Shapiro, page 139). If soap root, a ubiquitous native species in wild lands, were more commonly employed in San Francisco Bay area gardens the Brown Elfin butterfly would benefit. Especially since nowadays, in many wild land areas, deer are so numerous, eating the flower buds that serve as its caterpillar forage. Where deer are numerous soap root flowers tend to be scarce!

    Soap root is also listed as a caterpillar host for this moth:

    Tortricidae: Sparganothis senecionana.

    Some sources:

    Moldenke, A.R. 1971. Studies on the Species Diversity of California Plant Communities. Ph.D. Thesis. Stanford University. 355 p.

    Shapiro, Arthur M. & Manolis, Timothy D. 2007. Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions,

    Stockhouse, Robert E., II; Wells, Harrington. 1978. “Pollination ecology of Chlorogalum pomeridianum (D.C.) Kunth. (Liliaceae).” Bulletin of the Southern California Academy of Sciences. 77(3):124-129.

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