Now Blooming: Grindelia
A low bush with abundant yellow flowers is blooming now in patches along the western coast of the park and on the water’s edge nearby. The flower heads have the shape of daisies, with a ring of several dozen petals radiating from a center that has a mass of tiny yellow heads rising on slim stalks. When the flower heads are only budding, they form a tight cup that contains a sticky white gum. This gum gives the plant its common name, gum plant or gum weed, depending on whether you like it or not. Its scientific name is Grindelia, and it is a member of the daisy or sunflower family. There are several species of Grindelia. The one in the park is very probably Grindelia stricta, often called Oregon gum plant (or gum weed). Like many other plant names, this one is misleading. Stricta is a California native, with one nursery going so far as to say it’s a Bay Area native. Coastal gum plant is a more accurate common name mentioned by Calscape.org, the California native plant society’s website.
By whatever name, Grindelia is a magnet for pollinators. I saw several bees at work despite the stiff breeze that kept the flowers waving erratically, and I managed to photograph one of them. There are some bees that specialize in Grindelia pollen and will touch nothing else.
The gum that the plant produces gets a lot of mention in the online literature. Native Americans are said to have used it for chewing gum, or as a glue, or as a salve for poison oak. The gum is said to be a repellent to predators. When it grows in soils high in selenium, Grindelia takes up the selenium and stores it in its leaves. Selenium can be toxic to mammals. For this reason, ranchers try to keep the plant off their ranges. The gum may also be a trap for crawling insects such as ants. Native Americans are said to have used a tea made from the leaves for coughs, bronchitis, or inflammation of the respiratory tract. I have not seen work that tries to test these medicinal claims.
Grindelia varieties have commercial value for coastal gardeners, and can be purchased at nurseries. They are valued for drought tolerance, long blooming period, and attraction to pollinators.
I photographed this plant in the summer of 2015. I don’t recall it making much of a show in the intervening years. This summer it’s booming and well worth a stop and look. Grindelia spreads its floral sunshine in the middle elevation, above the ground-hugging Birdsfoot Trefoil and below the high-level Fennel.
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