Mt Wilson Toll Road to Henninger Flats

The Mount Wilson toll road is a well-maintained dirt road that the LA county fire department uses to access their station at Henninger flats.  There's a gate off Pinecrest Road in Altadena - it's open to foot or bike traffic from sunrise to sunset every day. The segment from Altadena to Henninger flat is not the most beautiful hike in the San Gabriels (personally, I would rank it near the bottom of the list!), but there are some nice views and for me it's a convenient way to access more interesting territory higher up.  Also, this area was not touched at all by the Station Fire of 2009, so as of early 2012 there is still lots of mature chaparral along the slopes that the trail passes.

It can be a rough hike in the summer - there is very little shade and it's a steep climb in some places (the bridge is at about 1200' elevation and Henninger is at 2400').  But in the winter it's quite pleasant - some of the side canyons get almost no sunlight.

It's about a 5 mile round-trip hike from the Pinecrest gate in Altadena to Henninger. You can also start at the Eaton Canyon visitor center parking lot (off Altadena drive, just north of New York Dr), which is about a mile and a half down from the bridge over Eaton Canyon.  The trail between the visitor center parking lot up to the bridge (and under the bridge to a nice waterfall a little ways back) can be extremely crowded, especially on weekends.  Also, keep in mind that in late 2011, the county installed a gate at the Eaton Canyon visitor center parking lot which is open only from 7:30am to 5pm.  If you want to get an earlier start, you'd have to park on the street.

I headed up the trail towards Henninger on a warm January day.  Here's the bridge over Eaton Canyon:

Here's some Encelia farinosa.  It seems early for these to be blooming, but it's been a very warm and dry December and January.

Encelia farinosa

This is the view towards LA at the intersection of the Walnut Canyon trail and the Toll Road:

The Walnut Canyon trail drops down to Eaton Canyon from here.  A couple of months ago, the trail was widened and cleaned up a lot, so it's pretty easy going at the moment.  Expect more crowds along this trail than on the Toll Road, though.

There's a grove of mediterranean pine trees on the left side of this picture. Tom Chester says that many of these non-native trees were planted by the Sierra Club for shade along the trail.  These trees at least aren't invasive, unlike some other plants (see below!).  It's not the best trail for learning about the native plants of California.

Above this point, there are a few more switchbacks and you reach Henninger.  At Henninger Flats, there's a fire station, a museum, and a tree nursery.  They say that the purpose of the forest is for conservation, but since they mostly grow non-Californian planets I get the feeling that at one point they wanted to find out if they could commercially grow a bunch of trees in the San Gabriels.   In any case it makes a nice shady spot to hang out and look down on "civilization."  There are campsites available as well, though I've never slept up here.

Eaton canyon, Pasadena, and LA. viewed from Henninger flats.

It might be hard to tell from my mediocre photos, but it was clear enough that day that I could see Santa Barbara island as well as Catalina.  I'm always amazed by how loud the city is - on the hike up the toll road in some places you are suddenly shielded from the sounds of cars and it's wonderfully quiet.  Then you turn a corner and are blasted again.  That sound must be bathing all of us city-dwellers all the time but we have grown so used to it that we don't even notice.  Another reason to get far out into the wild as much as possible!

Henninger flats is high enough that you can start to see some high-elevation mountain wildlife.  There are lots of nuthatches up there, along with mountain chickadees, Stellar's jays, western bluebirds, and a few sparrow species.  There has been at least one white-headed woodpecker hanging around for several months, which is surprisingly low elevation for that species here in the San Gabriels.  There is also a beautiful leucistic red-tailed hawk (that means lacking pigment in its feathers, but not truly albino) that is often seen around Henninger flats.  Unfortunately I was not able to photograph either on this trip.

White-brested nuthatch at Henninger Flats

There are Western Grey Squirrels up there - they look so much more fluffy than the introduced Fox Squirrels or the California Ground squirrels that live down in the LA basin.

If you head up from here you can hike all the way to mount Wilson - though it's another 7 miles one way.   This time, I was on a schedule, so I had to head back down.

On the way down, I noticed an entire hillside covered with fountain grass; this stuff:

Fountain grass

It's a popular yard plant with pretty purple seed tufts.  It originally comes from the drier parts of Africa and Asia, so it does extremely well in California's mediterranean climate.  The problem is that those pretty seed tufts are so prolific that the plant has a nasty tendency to push out every other living thing, like in this spot.  Pretty much every little yellow tuft in this photo is a clump of fountain grass:

Hillside covered in fountain grass

I'm not sure how you would get rid of it here -  the only thing I can think of is 1. apply a massive airdrop of Roundup, 2. burn the entire hillside, and 3. repeat monthly.   The location is here.

This is an even nastier invasive plant, the Castor Bean:

Apparently the government encouraged people to grow it here in southern California during World War 2 because it can make a nice aircraft oil (and laxative!).   But the plant produces all kinds of weird chemicals, including ricin.  Harvesting the beans can give you permanent nerve damage.  So if you ever have to handle this plant, please wear gloves and a lot of clothing. 

This is an interesting report on the status of invasives in LA from the friends of the LA river.  It's from a decade ago, but it puts Castor bean as its highest priority to remove.  Maybe environmental groups could get Homeland Security grants to try to eliminate castor beans, so people like these dudes in Georgia won't be tempted.

I was able to bring my homemade GPS for a field test on this hike - more on that soon.