War of the Plant Worlds at Benicia State Recreation Area

There is a silent war being waged in Benicia State Recreation Area and Bert Johnson, a city resident and a top-tier botanist, is standing in one of its battlegrounds.

“See this?” he says in a disgusted tone. “This is a bad, bad actor, a serious pest.” 

This bad actor is a green shrubby plant known as a privet, whose branches are snaking around a willow tree in this tunnel-like canopy of foliage just off the east side parking lot of BSRA. The privets are slowly pushing the willow out of this green space and will eventually destroy it, which is what makes Johnson so upset: “This is an invasive, obnoxious weed that spreads and raises hell with our waterways and creeks. In my opinion, it’s the number one enemy to California ecology in this area.”

The privet is, in botanical lingo, an “exotic,” a non-native plant originally hailing from the Far East. The willow is an indigenous California tree often seen around water. Come across some willow trees, and there’s likely a creek nearby. Being an evergreen, however, the privet sucks water from creeks and dries them up, striking a death blow over time to the willow.

From the understory Johnson leads me further down the dirt trail that curves around the edge of Southampton Bay.

We stop at two willows engaged in a kind of mating dance. “Willows are males or females,” he explains, pointing out the female of the species, which has greenish “catkins” or flowers that are starting to emerge. Cozying up to it is the male. The male flowers are yellowish in color.

Bert laughs. “You can tell I’m a plant nut,” he says. “Totally. Some people consider people like me to be crazy. And we are a little eccentric, I admit.”

A retired gardener with the Regional Parks Botanic Garden and an acknowledged botanical expert (he was featured in last month’s issue of the magazine), he nonetheless expresses serious displeasure at how badly the California native plants are faring in their centuries-old struggle with foreign transplants such as the privet. 

We walk past a thick clumpy row of Himalayan blackberries, which also hail originally from foreign shores and have found a home in the mild climes of California. In spring they produce little berries that people pick and eat.

Female willow

Female willow

Bert at the Benicia State Recreational Area

Bert serveys the Benicia State Recreational Area

“So, what’s so bad about that?” I ask.

There’s nothing wrong with that, says Bert, except for the rolling effect that the loss of natives, such as the willow, has on birds, bees, insects, butterflies, and other natural life in the area. “Birds nest in willows,” he remarks. “The Indians would weave baskets using willow bark. It’s been part of the California landscape forever.”

The privet, Himalayan blackberries, fennel and other exotics tend to create what Johnson calls “monocultures.” They dominate an area and squeeze out most everything else. Whereas, he says, “Natives grow sporadically. They don’t take over everything. They allow space for other plants to grow with them. Which creates diversity and balance, a living ecosystem.”

We have moved to another part of the trail where the alkali goldfields make their home.

The goldfields are one of many native plant species found in BSRA, including common tules and California tules, California sunflower, toyon or California holly, pickleweed, Western needle grass, the pipevine plant, Western dock, and marsh butterweed. To our west is the expanse of pickleweed marsh that occupies so much of Southampton Cove.

It is early spring, and the surrounding hills are a vibrant green while the marsh is a dreary grayish-brown. But, as Johnson points out, practically in the blink of an eye the script will flip: golden brown hills, green marsh. 

“The whole scene changes. It’s a total reversal,” he says with boyish wonder. “Nature is amazing, isn’t it?” Next month, in the last in our three-part series on BSRA, we go on a promenade in the park.