Everyone knows the trees grow colorful during autumn, but other fall sights await you on San Diego’s hiking trails. A few are fitting for Halloween. . . .

Pretty Poison
This time of year, poison Oak, which grows along many local trails in San Diego, can turn vibrant red and yellow. The big bouquets of color lure unsuspecting passersby to touch. Don’t, of course. Remember the three-leaf rule, and be on the watch for colorful foliage that stretches pretty tendrils across trail tracks, and twining up trees. The general rule is “leaves of three, let it be.” More specifically, poison oak’s three-leaf configuration grows with two leaves on either side of the stem, and one extending out like a middle finger (see close up). It’s easy to keep this in mind, and avoid this plant that gestures its irritating nature.

Witch’s Hair
This is the popular nickname for the parasitic plant more officially known as California Dodder. This fleshy gold or orange colored parasite grows in hairy, wig-like clumps over shrubs, brush, and even cactus. Other than its looks, there’s nothing really “witchy” or dangerous about California Dodder to humans. In fact, the Kumeyaay Indians native to our area used to pick and brew California Dodder as a tonic for black widow’s bite. But witch’s hair acts as a vampire to the plants it hosts upon. It latches on and sucks the life right out of them!

Spittle Bugs
Yuck! Are those wads of spit clumped on plants along the trail? No worries. An uncouth hiker didn’t leave you a disgusting surprise. Those wads of spittle are actually the protective covering of the spittle bug nymph, which surrounds itself with a mass of slimy bubbles formed from plant juices and fluids from its own body. In time, the harmless spittle bug nymph grows into an adult and leaves the spittle wad to venture out into the world. The tiny adult spittle bug holds the record for the high jump, with an ability to hop to heights over two-feet. The scientific journal Nature reported on an actual spittle bug study. The lead study scientist says the bug’s jumping ability is the equivalent of a human jumping over the Gateway Arch in St. Louis. That’s 630 feet high! Worried about getting hopped on by the adult spittle bug? Don’t be. It’s elusive and harmless, hopping but not . . . mad.

Rattlesnakes
Hibernation is tied to low temperature, not necessarily the turning of a calendar page. In San Diego’s sometimes warm fall climate, rattlesnakes can still be out and about.