Bay Nature magazineSpring 2017


What Leads to Great Wildflowers? The Formula’s Not Always So Easy.

March 28, 2017

Water water everywhere! It’s been a while since we’ve had a winter like this. No surprise, it’s raining as I write this note in late February, and we’ve already had rain in 36 out of the 54 days in this calendar year. Of course, this is mostly a good thing, given the preceding five years of drought in the region. Water is essential to our economy, our ecosystems, our lives. But can you have too much of a good thing? In some places, yes indeed, as water simply doesn’t respect road signs, property rights, or even people’s lives in its inexorable gravity-propelled descent toward the ocean (or into our basements).

And on the minor annoyance end of the scale, it’s been hard to get outside for hikes (or restoration work days) because it’s been raining or the trails have been so muddy. Attempting to look on the bright side, several people have remarked to me, “Well, at least we’ll get great wildflowers this spring!” Perhaps; but there isn’t a one-to-one correlation between rain and great wildflowers. There are many factors that lead to great wildflowers, and ample moisture is certainly one of those. But lots of rain can also lead to prolific growth of the nonnative annual grasses that form most of that lush green carpet on our Bay Area hillsides. The thick mats of exotic grasses such as ripgut brome and wild oat that are going gangbusters right now may very well outcompete the native wildflowers waiting underneath for a little warm sunshine in order to germinate. So, as of late February, the jury is still out on this year’s wildflower bloom.

Of course, we could just enjoy the ubiquitous sourgrass (Oxalis pes-caprae) that’s carpeting yards and fields with its bright lemon-yellow blooms. If pretty color was your only criterion, you could say, well, what’s wrong with sourgrass? The problem is, like the now-dominant Mediterranean annual grasses, this oxalis is not only nonnative, it’s also invasive. Which means that in our local environment, it’s not subject to the factors that limit its spread in its South Africa homeland; when let loose here, it quickly crowds out local native species and converts formerly rich and diverse native ecosystems into veritable monocultures.

Let’s be clear: Working to keep nonnative species out of our local ecosystems is not equivalent to the xenophobic anti-immigrant policies of the new administration in Washington, as some have suggested. All human beings are one species, Homo sapiens. Ergo, in places where people already live (leaving aside the question of whether we should be living there), no human being is “nonnative.” Immigrants tend to increase diversity; invasive plant species decrease it.

One final thought about all this water and its destructive potential: The climate scientists told us so. Their models for California have long predicted extended periods of drought, punctuated by extreme flood-causing rain events. So, you know, the worst of both worlds. The Trump administration’s reversal of recent hard-won baby steps away from reliance on fossil fuels will only exacerbate this destructive pattern. So it looks as if we’d better install bigger rain barrels for droughts and more powerful sump pumps for bigger storms. Create defensible space against wildfire and purchase flood insurance. Buy stronger sunscreen and better rain gear. And then write our public officials to tell them what we think. And keep an eye out for those native wildflowers, because it just might be a good year for them after all. And wouldn’t that be a welcome balm in troubled times.

About the Author

David Loeb was the co-founder and Executive Director of the Bay Nature Institute and the publisher of Bay Nature magazine. Now retired, he continues to roam the trails and waterways of the Bay Area and points beyond and contributes occasional articles to

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