The World of Soaproot

Howie holding soaproot bulb

Howie holding soaproot bulb

During one regular volunteer nursery program here at Mission Blue Nursery, rescuing a few nondescript plants from a weedy invasion in their gallon pots turned into an impromptu lesson and discussion of the virtues of Soaproot (aka Wavyleaf Soap Plant), Chlorogalum pomeridianum. Overrun by oxalis, Howie, a long time volunteer, removed the entire plant from its pot in order to detangle the labyrinth-mess of oxalis roots, which if any are left behind, will only allow the pesky weed to re-sprout. Finally he extracted our friend, Soaproot.

Howie’s holding the plant by the bulb that gave Soaproot its name. Gelatinous when crushed and mixed with water, this sizable bulb was used by our local Ohlone Indians for for many purposes. As a soap, it is good for washing hands and body, hair and clothing. The bulb is protected by a thick outer husk, which was removed and used as a brush. The bulb itself is also edible and was slow roasted in ground-pits. Multipurpose, the crushed bulb contains a kind of poison that when placed in a pool would stun fish and allow them to be easily caught1.

Although not commonly used in the horticultural industry, Soaproot should be. The alum-like leaves are quite attractive and the long stalk of delicate white to purple flowers that emerge in the spring are truly lovely. It grows to 1-3 feet tall and wide and is found in some abundance on San Bruno Mountain.

Adding to its mystique, its flowers only open at dusk, or on a foggy day, but never in full sunlight. Many flowers that are pollinated by nocturnal insects will either open in the evening or let out their alluring aroma only once night falls. I found no research indicating that Soaproot is pollinated by night flying moths or bats, but instead it seems to be pollinated by our native bumblebees. The plant benefits from dusk flowering by offering these bees a reliable nectar and pollen source at a time of day when the insects don't have to suffer through excessive heat and sun2 . Soaproot provides a niche food source that the bees readily take advantage of.

The only reason I can imagine why it might not be more widely planted in the garden is because it is a summer-drought dormant plant, loosing its leaves with the dry heat, it dies back to the ground, beginning to sprout again with the winter rains. Many worthy plants are ignored by the nursery trade because of their seasonal dormancy. In California, where some people claim we have “no seasons,” these plants speak otherwise. While we might not have the dramatic temperature variances of the North East, our California plants are uniquely adapted to our summer dry/winter wet climate.

It is a pleasure to watch these subtle seasonal changes happen through your plants and, rather than discount plants that become more modest in our Indian summers, we should see this as what makes them uniquely Californian and a reason to love them, and plant them, all the more.

We’ll be offering this plant and many more at our upcoming plant sale in February. See you there!

    — Ildiko Polony, Mission Blue Nursery Manager

[1] Golden Gate National Parks Conservancy. 2015. "Chlorogalum pomeridianum."

[2] Stockhouse, Robert E. II and Wells, Harrington (1978) "Pollination Ecology of Chlorogalum pomeridianum (D.C.) Kunth. (Liliaceae)," Bulletin of the Southern California Academy of Sciences: Vol. 77: Iss. 3.