The hike begins with a pleasant canopy of sycamore, mule fat, willow, and other riparian plants that line Lopez Creek. The trail sometimes crosses the creek, so watch your balance on wet rocks. Poison oak thrives here in large stands and up on sycamore trees, so know how to recognize it before you go. Despite the plant’s toxic nature, it can be lush and beautiful.
There is a mix of native and nonnative plants. Native plants include coyote brush (baccharus), elderberry, miner’s lettuce, black sage, tarragon, fuchsia-flowering gooseberry, lemonade berry, laurel sumac, blue-eyed grass, California and San Diego sunflowers, monkey flower, and wild cucumber. The green, spiny fruit of the wild cucumber has a striking appearance. Plants such as plantain (a very low-growing, small monocot), blackberry, jimson weed, and thistles can be either native or non-native, depending on the species. Nonnatives (some from the region’s cattle-herding history) include rye grass, oats, wild geranium, black mustard, horehound, curly dock, pineapple weed, plus various filaree species.
There are many gopher holes lining the trail, and you may see one poking its head out of a hole. Funnel weaver spiders take advantage of vacant gopher holes to set up their nests as well as dotting the hillsides with their funnel-shaped webs. If you go early in the morning, the webs glisten with dew. The trail ends to the right of the kiosk and uphill to the Pacific Mesa Boulevard cul-de-sac near the intersection of Pacific Center Boulevard, where limited parking and some seating areas provide for a leisurely lunch before returning to the west entrance.
An alternate route is to add an additional 5 miles by then following the trail under the Sorrento Valley Boulevard bridge to the waterfalls. The waterfall hike at Los Peñasquitos (little cliffs) Canyon Preserve offers a welcome retreat without a long drive or strenuous exertion to get there. The preserve spans 3700 acres with over 10 miles of trails. Be aware that you will share the trail with horses and bikers throughout the preserve, so be alert to whoever shows up ahead of you or behind you. Wildlife does include coyote and mountain lion; so hiking with a partner is prudent.
The relatively flat trail immediately offers numerous native plant species to view. Black sage perfumes the trail, sharing space with scrub oak, coast live oak, chaparral broom, chamise, manzanita, California sagebrush, checkerbloom, yucca, prickly pear, chalk dudlia, buckwheat, and many other species flowering at various intervals through the spring, summer, and fall. The trail has limited shade, so be sure to bring water, sun protection, and sturdy hiking shoes with good ankle support. Much of the route is lined with rounded, ancient river rock, carried from the Sonora, Mexico region by the San Andreas Fault over millions of years of seismic activity. As you near the junction to the waterfall, looking to the right up the hill will reveal a red shelf-like structure capping lighter colored rock. This is a Linda Vista rock formation, originating from ancient, iron-rich shoreline deposits again originating in Mexico and carried north over time by seismic fault motion. Wend your way carefully over the rocks to get down to the water. Return via the same trail.
For more information on the Los Peñasquitos Canyon Preserve, see the link to the area map at penasquitos.org. The park may be closed during heavy rains or a couple of days following rain. Normal park hours are 8:00 am to sunset.
Distance from downtown San Diego: 16 miles. Allow 25 minutes driving time. From I-805 N, exit on Mira Mesa/Sorrento Parkway then keep in the left lane and go straight through the intersection. Continue north to Sorrento Valley Boulevard and turn right. Roughly a mile later, the park entrance will be on the right. Keep a sharp lookout since the Los Peñasquitos Canyon Preserve sign is not visible until you are almost on it, and you will not be able to make a U-turn for about another mile down the road.
Hiking length: About 2.5 miles from the west end to Pacific Mesa Blvd and return or 7.5 miles, combining the Lopez Canyon section plus the falls and back. Difficulty: Moderate — approximately 120 feet change in elevation with short creek crossings over round rocks.