The Mystery of Kern River Washingtonia filifera: Native or Naturalized?

The Mystery of Kern River Washingtonia filifera: Native or Naturalized?

Hello fellow garden enthusiasts!

I recently stumbled upon a fascinating discovery – a population of Washingtonia filifera growing along the Kern River in Kern County, California. As I was scrolling through photos of the Sequoia National Forest, a picture caught my eye. It depicted a native grove of filifera, beautifully thriving along a river lined with steep cliffs, surrounded by abundant grasses and trees. This sparked my curiosity about the location, as it seemed quite different from the typical Sonoran Desert ecosystem where the palm is usually found.

To my amazement, the International Palm Society magazine listed this population as a native one, “at the northern limit of the species’ natural range in California.” The grove is located in the Kern River Canyon, near the entrance, with several palms scattered along the river and cliffs.

The Mystery of Kern River Washingtonia filifera: Native or Naturalized?
The Mystery of Kern River Washingtonia filifera: Native or Naturalized?

The Kern River Palms

I couldn’t help but dive deeper into the research to determine whether these palms are truly native or simply naturalized. When I searched for old photos of the canyon’s entrance, I found a striking absence of visible palms in almost all the pictures. The black and white, often grainy photographs made it difficult to confirm if palms were actually present.

However, several factors may explain this absence. One possibility is that the palms were never there in the first place, and the photos simply do not capture them. Another hypothesis is that Pacific Gas and Electric (PG&E) removed most of the palms. In 1921, PG&E constructed a hydro-electric plant near the canyon’s entrance and a water bypass above the main grove of palms, resulting in a waterfall after heavy rains, potentially stimulating additional palm growth. Additionally, several buildings that once stood by the river, near the main grove’s current location, have since been demolished. It is also plausible that some palms were washed away during the frequent floods caused by storms and upstream snowmelt in the powerful Kern River, prior to the construction of dams. The recent street view image shows many palms half-submerged after heavy rainfall this past winter.

The Mystery of Kern River Washingtonia filifera: Native or Naturalized?

A Glimpse into the Past

One undated photo piqued my interest as it seemed to reveal visible palms. Judging by the cars, I estimated it was taken in the 1960s or 1970s. The size of the palms suggests that they had been there for quite some time.

The Mystery of Kern River Washingtonia filifera: Native or Naturalized?

Insights from “A Flora of Kern County, California”

My research led me to a fascinating book from 1967, titled “A Flora of Kern County, California,” written by Ernest C. Twisselmann. In this book, the author refers to the palms as “eight spontaneous trees,” considering them to be naturalized. However, it remains unclear whether this classification is based on verified facts or just a casual observation, as they are not officially recognized as native to the county. Nonetheless, the presence of palms back then is undeniable, although it is uncertain whether the count of eight is accurate or an estimation. Remarkably, there are now significantly more palms in the area.

The Mystery of Kern River Washingtonia filifera: Native or Naturalized?

Nature’s Enigma

The setting of the groves, with the palms clumped together and occasional outliers, gives the impression of a native landscape. It is noteworthy that these groves are quite distant from the next closest native grove, which is not unusual. Similar outlying groves in southern Nevada and central Arizona are also located far from the abundant Southern California/northern Baja region where Washingtonia filifera is typically found. Moreover, these groves are far from any other California fan palms that could have led to their naturalization. Additionally, many of the mature palms in the grove are decades, if not over a century, old. This suggests that there were fewer filifera in the area when these palms first germinated. Interestingly, despite the presence of robusta palms nearby, which are notorious for their ability to naturalize easily, they have not mixed at all with the filifera grove along the river.

Now, I turn to you, my fellow enthusiasts, with an invitation to share your thoughts: Are these palms native or naturalized? Your insights and opinions are greatly appreciated. Let’s unravel the mystery together!

Thanks ?