Hey Ranger: Redwood sorrel: giants’ understudy

By Lynda Mealue April 01, 2013 06:06 pm

 “You can’t see the forest for the trees.” This cliché, used many times in regards to the coast redwood forest, is for the most part true, until you actually take in the bigger top-to-bottom picture of an old-growth redwood forest.

When you look lower, to the base of the trees, you will begin to notice the remarkable understory of unique plants that have continued to accompany these giants for hundreds of years. Not unlike the community in the popular television series, “Downton Abbey,” there is an upstairs household and a downstairs household that together create one smoothly intertwining community. 

My personal favorite of the downstairs group of plants is the redwood sorrel, Oxalis oregana, a beautiful member of the Oxalis family that can create thick mats of green carpet right up to the enormous trunk bases of the towering trees.

 

Local children and park visitors sometimes call the redwood sorrel “sour-grass,” “clover,” or “shamrock;” however it is none of these plants at all! Sorrel is a perennial herb in a totally different family, some members of which can grow up to almost 12 inches in height.

This shade lover is one of the few plants that can thrive in the dense shade of the coast redwood forest. The acidic soil created by decomposing redwood needles and woody debris would kill many common garden plants, but this formula is just perfect for sorrel to flourish.

The deep, lush mats of sorrel develop from tuber root systems; some mats can represent over 150 years of undisturbed growth. One great place to view mats like this is near the restrooms at Jedediah Smith Redwoods State Park’s day-use picnic area, as well as along many of the trails off of Howland Hill Road.

Redwood sorrel adds to the magic of the redwood forest. Both the coast redwood and the redwood sorrel have low tolerance to drought, so they have interesting strategies for gathering water. Redwoods have very shallow, large root systems that spread thin, hair-like roots out 100 feet or more to gather moisture from the soil.

Intertwined in the lattice of redwood roots, you may have noticed umbrella-like, folded leaves belonging to sorrel. Leaf folding happens in order to conserve moisture when sorrel leaves are exposed to bright sun or when dealing with periods of drought. Sorrel will even fold in heavy rain, reducing the impact of raindrops on the leaves and re-directing the water downward to the base of the plant.

Folding is a fairly rapid response, taking only a few minutes; if you are patient enough you may actually be able to watch the plant fold or unfold. 

Unlike the redwood, the stems and leaves of the sorrel are edible. Sorrel’s sour taste is responsible for its Latin name “Oxalis,” which means “acid juice.” Sorrel stems and leaves have been used for adding an extra zing to salads and were even made into pies by past pioneers.

But, be aware you may not harvest them in the parks, and eating too much of them can make you sick enough to get your stomach pumped! 

Another intriguing aspect of the heart-shaped sorrel leaf is that when viewed from above, the leaf itself is dark green on top with a beautiful burgundy fuzzy underside. When viewed from below with a dentist’s mirror or flipped and held up to the light, the leaf’s color magically changes! This is due in part to how the tiny hairs on the underside of the leaf reflect light.

You will find tiny sorrel flowers blooming from February through September. Sorrel’s single-stalk, five-petaled flower initially blooms white with dark pink veins and turns dark pink as it ages. At this time of the year the sorrel flower is a welcome sign of spring, just like Easter!

As a child I grew up near an old growth redwood forest on Lake Earl Drive. When playing with my friends, our time was divided between the trees and the ground. Tree-play included a rope swing; ground-play usually involved searching for “four-leaf-clovers” in the sorrel patches!

During my years working in the parks I have learned many amazing things about the redwood forest’s upstairs community, and that the forest is so much more than just a playground! Even now, after craning my neck looking up at the trees, I still love to rest my eyes by viewing the downstairs community with whom I feel most at home because of its splendor.

Perhaps the cliché should actually be, “You can see the forest for the trees.”