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Treebeard's Stumper Answer
12 October 2001

Late Bloomers

I'm ready for rain. It's been six months since we had a real storm here in central California. But look closer. Some native plants like the Coyote Bush in Julie's restoration area at Dunn Middle School are covered with white and yellow flowers. Most garden plants would be long gone without any summer water, but these natives are thriving. There are even a few summer mushrooms! I expect nature to make sense, but this is a puzzle. What other native plants wait until late summer and fall to flower? What benefit do these late bloomers get from flowering at the dry end of our summer drought, long after all the other native plants are finished?

Coyote Bush (Baccharis pilularis) is not our most beautiful late bloomer, but it is common, interesting, and important. It's a woody shrub in the Sunflower family (Asteraceae). It's interesting because it flowers in late summer, and it is dioecious with separate male and female plants. The female plants (left) have white flowers that develop fluffy dandelion-like seeds. The male flowers (right) are yellowish and produce abundant pollen that attracts insects, especially many different species of bees. They make me sneeze, though they are not wind-pollinated. Why does it flower so late in the year?

Coyote Bush is often maligned because it colonizes waste areas and vacant fields, replacing grassland with coastal chaparral scrub. I was happy to find a defence from the Friends of the Coyote Bush. Coyote Bush provides shelter for wildlife and a nursery for native plant seedlings. A school administrator once commented that Julie's restoration area at school was great "except for all that darn Coyote Bush." That was missing the point. Birds and rabbits find shelter here. It gives essential cover to dozens of Valley Oak (Quercus lobata) seedlings and even a few native California Black Walnuts (Juglans californica) that the birds probably dropped. These trees will outgrow the shrubs in time. This is the first step of real ecological succession in action. It gives me an idea of what the Santa Ynez Valley originally looked like. There's concern about the vanishing oak woodland in California. I'm sure the humble Coyote Bush is part of the answer.

Late summer flowers get the same benefit as all late bloomers. They bloom after the others are done. For plants like Coyote Bush, that means less competition for space, pollinators, and the little water that remains, including fog drip. I see swarms of bees, wasps, flies, and even hummingbirds on our late flowers. Conditions are harsh now before the rains begin, so these late flowers are important for many critters. Since our plants and animals adapted together, maybe the whole ecosystem needs these late bloomers to support the pollinators for next year?


Here are a few more thoughts about late bloomers:

Sawtooth Goldenbush
(Hazardia squarrosa)
San Marcos Pass, October 2001
Coastal Goldenbush
(Isocoma menziesii)
Gaviota Beach, September 2001
Rough-Leaved Aster
(Aster radulinus)
San Marcos Pass, September 1998

I haven't found many links about this stumper that I haven't already mentioned. CalFlora has info and photos of the California Flora. The Pollination Home Page has info and great photo albums of late summer pollinators of Goldenrod and Aster. The Ecological Society of America has a concise fact sheet on pollinators.

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Copyright © 2001 by Marc Kummel /