May 2016 – Garden Report

Survival of the Fittest: San Francisco Gumplant

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This time of year you may notice a couple of low sprawling plants with yellow daisylike flowers in front of  Salumeria and Central Kitchen. This is San Francisco Gum Plant, (Grindelia hirsutula var. maritima) specifically native to San Francisco’s maritime climate.

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Gum Plant (which also goes by the much less attractive name Hairy Gum Weed) is native all over the U.S. and Canada, but can look different enough in different places for botanists to classify some plant populations as separate varieties. San Francisco Gum Plant (maritima variety) is limited (endemic) to the coastal areas of California in and near San Francisco – and nowhere else. Unsurprisingly, it is considered a rare and endangered plant. And yet under the right circumstances, it’s a truly tough survivor.

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Gum Plant is so known because the flower buds are topped by a drop of white gummy material, and the leaves are resinous. These resins defend the plant against insects and also prevent water loss, making the plant highly drought-tolerant. This explains why SF Gum Plant is one of the few plants to have survived 3 years of drought on the sun-baked corner of 20th and Florida. Its patience has been rewarded by a normal rainy winter so now it can really spread out and do its thing. Most sources say that the plant flowers in late summer and early fall, but it’s blooming in spring on our corner.

Native Americans pulverized the leaves to apply to sores and poison ivy, or to use internally as a sedative or to treat respiratory conditions. The resin produced by some related gum plants has industrial uses including the production of rubber, paints, and varnishes.

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San Francisco Gum Plant is a great addition to your drought-tolerant garden. It grows in full sun and in a variety of soils. It supports a variety of bees and butterflies in the summer and fall when many spring-blooming natives have finished flowering. Recommended native companion plants include seaside daisy (Erigeron glaucus), low-growing ceanothus and manzanitas, and coast buckwheat (Eriogonum latifolium). Other related – and similar looking –  native gum plants include Great Valley Gum Plant (Grindelia camporum) and Spreading Gum Plant (Grindelia stricta). But if you can plant the maritima variety of Grindelia hirsutula, you are helping to keep an endangered species going.

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Find gum plants at native plant nurseries such as Bay Natives in San Francisco, California Flora in Fulton or Watershed Nursery in Richmond, or the California Native Plant Society’s periodic plant sales.

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