Lost Palm Oasis: Found!
I'm of the opinion that Palm Oasis are one of the most interesting natural features of inland southern California. Some are hard to get to, like Mortero Palms. Some are very easy to get to, like Mountain Palm Springs, or Borrego Palm Canyon. This one is moderate, as access is paved, but there is a 7 and 1/2 mile round trip hike. However, in an often crowded national park, that hike distance thins the heard and lends itself to some solitude at times of year with the nicest of weather, when in the oasis.
Leaving from Cottonwood Springs, pass through the lovely oasis vegetation of tall palms and cottonwoods. Pass the intersection for the loop to Mastodon Peak, and continue on this lovely trail all the way to the Oasis. Along the way, you'll enjoy fantastic upper Colorado (Sonoran) Desert scenery, views of boulder fields in the Eagle Mountains, and distant desert vistas. You might look back and catch a glimpse of San Gorgonio, but probably not San Jacinto, above some of Joshua Tree National Park's Little San Bernardino Mountains. If in winter or spring of a good year, San Gorgonio will be snow covered. A small portion of this hike follows a sandy wash, but most is on the uplands.
Nearing the end of the trail, a sign indicates your destination below, just before your final descent to the Lost Palm Oasis. Explore the oasis, stay on rock as much as possible to avoid vegetation and soil compaction, and do your best to protect the oasis ecosystem by not damaging plants, water sources, or other features. The trail is marked with mileage signs, and at the end of the oasis, just past the last of the palms, mile marker "4" is on the south slope. Return the way you came, and enjoy!
At the time of this writing, near the lower end of the oasis, a different kind of palm has been seeded in, most likely by human (not me) sources. A true date palm of about 3 or 4 years of age, is currently growing. In time, this may get larger and become an addition to the oasis, or the NPS may correctly choose to remove it as an exotic species. Date palms are dioecious, and are either male or female. This is probably a seed from one of the local Medjol Dater Palm orchards, brought in during someone's lunch, and growing after being left behind. A single date palm, being male or female, will be unable to reproduce in this isolated location. However, it can create a small colony by pupping, or growing side stems from near the ground.
Check out the Official Route and Triplogs.