Even in a heavy rain season, the double falls that bring most visitors here (Moss Grotto and Ribbon Rock) may not be flowing, but that's no reason to avoid this hike. The interesting history, killer view of L.A., and the plant life are worthy of their own excursion.
At the turn of the 20th century, Rubio Canyon hosted a tram that led to Echo Mountain and a service pavilion for its passengers. The tram cars were dubbed "white chariots," and they ran from 1893 to 1936. In 1909, though, Rubio Pavilion was destroyed by a storm and the resultant errant boulders. Some of the foundation remains today, and it can be seen along the trail along with occasional glimpses of the previous rail bed.
In winter and spring, a multitude of wildflowers and even mushrooms can be found along the trail. At the first trail intersection, take a few moments to stop at the small teaching garden and learn about the native plants you'll encounter on your trip.
A lucky visitor will be able to view the modest double falls of Moss Grotto Falls and Ribbon Rock Falls, which are dry most of the year. If the falls are dry, it's worth continuing along the canyon and scouting out the local flora. The trail eventually degrades and becomes a steep scramble up loose rock, so exercise caution when reaching this part of the canyon.
Dogs are allowed but not recommended due to the unstable trail with steep drop-offs.