It’s fall, so the Real Doctor and I have been riding our bikes in dimmer and darker conditions. Last week we had our first ride entirely with lights on. As many years as we’ve been riding in the fall twilight, we have smelled a lovely fragrance at certain places in the bike trail—but the source of the perfume remained a mystery. The scented area was rough, the residue of a time when the American River was dredged for gold. When we stopped to try to find the scent one evening, the only thing we saw blooming was buckwheat, which makes no fragrance.
A couple of Octobers ago we visited my folks in Pacific Palisades. On a hike up Temescal Canyon, we smelled the same smell in the dusk—but this time, there was no doubt as to what the responsible plant was, and no question why we’d missed it before.
If you wanted to design an invisible plant, you would struggle to make a less noticeable plant than Brickellbrush (Brickellia californica). The plant is not exactly ugly, but the eye does not want to linger upon it. It tends to be scraggly, its foliage small and a dusty drab color. Even though it can get pretty big, forming a shrub a meter tall, it’s just so plain that it’s hardly noticeable. Worse, the flowers are so tiny and plain that they’re practically unnoticeable—except for the scent. This picture is hugely enlarged.
You can buy Brickellbrush from some native plant specialists (the above photo is from one of them, Annie's Annuals--highly recommended). One of them advised planting it in some hidden part of the garden where you wouldn’t have to see it. The smell will still fill the entire garden.