One of our favorite palms for the garden is the US native Sabal minor var. louisiana. While it can’t outgrow the Himalayan Trachycarpus fortunei (windmill palm) for speed of developing a trunk, Louisiana palmetto is the most winter hardy of all trunking palms. One of the mysteries is that in the wild, the same population can have both above ground as well as subterranean trunks.
Our garden specimen in the photo below was planted from a 1 qt. pot in 2005. Eventually, Sabal minor var. louisiana will develop an above ground trunk, which on our specimen below is just beginning.
The background on Sabal minor var. louisiana is a botanical mystery. Some taxonomists consider it a valid species, while others consider it variety of the subterranean trunked Sabal minor. Others consider it to be an old hybrid of Sabal minor and either Sabal mexicana or Sabal palmetto. A similar hybrid, Sabal x brazoriensis from near Dallas, had its DNA analyzed several years ago, and was found to be an old hybrid of Sabal minor and a now extinct population of Sabal palmetto.
Sabal sp. ‘Tamaulipas’ from Northern Mexico is another mystery palm in need of some family history work. Thankfully, palm researcher and grad student, Ayress Grinage at Cornell has begun to look at these mystery sabal palms to figure out how they came to be. We, and others have sent material, and now await the results of the paternity test.