California oaks in their native habitat.

These are the starring attractions of Descanso Gardens’ Oak Woodland, a 7.7-acre space that re-creates the plant palette of the Los Angeles Basin as it might have appeared a century ago.

“We don’t really know what was here,” says Rachel Young, Descanso’s director of horticulture and garden operations. “We just know it was an oak habitat.”

Coast live oak and scrub oak dot the rolling landscape of woodland, meadow and chaparral plants.

Until recently, the area in the La Cañada Flintridge botanical garden was fenced off to the public and overgrown with towering eucalyptus and soft mustard grass, which many people equate with California but is in fact invasive. As the area was developed and built with Prop. A funds and support from the Ayrshire Foundation and the Men’s Garden Club of Los Angeles, plants were removed to make way for five California native habitats — coastal sage scrub, scrub oak chaparral, grassland, wetland and riparian.

Young pointed out each one as she led the way along the winding boardwalk, past centuries-old oaks and newly planted meadows of blue-eyed grass, California poppy, mugwort, purple needlegrass and toyon with its bright red berries. Songs of birds mingled with the honking of a lone goose seen feeding on weeds in the beds.

As Descanso Gardens’ first new addition in 30 years, Oak Woodland serves as yet another love letter to the region’s natural beauty.

“Because cities are getting bigger and less people are getting out into nature, we’re starting to exhibit native plants as something people don’t see anymore because those habitats are getting destroyed,” Young says.

It’s been going on since long before suburbia began sprouting.

About 100 years ago, Southern California was predominantly agricultural. With the completion of the Los Angeles Aqueduct, the region’s dryland farming and livestock rangeland was transformed into irrigated crops and suburbanization.

“Southern California, especially the flatter areas which are the most readily accessible by people and livestock, hasn’t been truly wildland for quite a long time,” says Polly Schiffman, a biology professor at Cal State Northridge. “When the Spanish came here and established the missions, they brought all sorts of cattle and sheep and even let pigs run loose on the landscape. And they were doing cultivation as well, so there were orange groves and vineyards.”

In the hills, people made less of an impact on native vegetation.

There are still pockets where mostly native plants and animals dominate the landscape, including the Santa Monica, Santa Susana and San Gabriel mountains.

“If you can get into those areas, the vast majority of shrubs and trees that you’ll see are going to be native,” says Schiffman, who regularly leads students on local outings to different areas to observe native plants. “The steeper slopes are much more pristine and more like it was all along, since before European contact.”

She adds, “The one thing about native plants is they produce these really tough little seeds that drop on the ground and then get incorporated into the first few inches of soil, and they sit there, and they’re viable. Sometimes they sit for years or decades and when the right environmental factors happen, boom — they germinate and you see them again.”

Like the Madrona Marsh Preserve in Torrance, Rancho Santa Ana Botanic Garden in Claremont and Theodore Payne Foundation for Wildflowers and Native Plants in Sun Valley, Descanso’s new native garden serves to raise awareness about the large diversity of plants that evolved in Southern California and are best equipped at dealing with its environment. Home gardeners can get advice on which plants are most likely to work at botanical gardens and nurseries specializing in native plants and wildflowers, such as Moorpark’s Matilija Nursery and Grow Native Nursery, which has locations in the Veterans Garden in Westwood and at Rancho Santa Ana Botanic Garden.

In re-creating Descanso’s heritage garden, Young describes simply looking down and around her at what was already growing.

“We had a few little places in the garden where you could see just a little bit of native habitat left,” she says. “We took some of the plants we found and added them to our plant list. We also looked at nearby areas and the plants that would have had a similar woodland habitat.”

A few ornamental natives cultivated for specific colorful blooms were also thrown in with the grasses, perennials, shrubs and trees.

For Young, few natives in the Oak Woodland top the perfectly shaped coast live oak at the top of the path or nearby scrub oak — a chaparral species that commonly grows in the tangled shrubland of surrounding hillsides.

Some of the Descanso Gardens’ trees are estimated to be 300 to 500 years old. They were survivors of a fire that ravaged the property about 140 years ago, Young says.

“That’s the reason you don’t always see a ton of them,” she adds, adding oaks are fragile.

Overwatering and urban development are just as devastating to an oak as fire.

“One of the reasons we started protecting an area just for oaks is because we noticed they’re not always treated the way they would like to be treated,” Young says. “If somebody has a beautiful oak tree in their garden and plants grass under it or paves over the roots, within 20 years the tree dies. This garden gives someone a place where they can come in 150 to 200 years and see the oaks grow.”