ELISABETH M. BROWN
It was April ten years ago, while driving along PCH near the Lucky's,
now Albertson's, shopping center, when I first noticed them -- large
dark green shrubs covered with white flowers on the South Laguna
hillsides. They were very showy, and I wondered about them because no
other part of the Greenbelt sported white flowering shrubs at that
time of year. In my typical coastal sage scrub neighborhood of Canyon
Acres, the slopes were sprinkled with yellow from the flowers of the
So I turned off and found my way to the closest of the bushes. The
leaves and everything else about the mysterious plant indicated that
it was one of the large group of California lilacs, or Ceanothus.
Particularly intriguing was the color of the flowers: white instead
of the more typical lilac blue.
Biologist Karlin Marsh's survey of South Laguna confirmed that
there are two kinds of native lilacs in South Laguna.
For the botanically challenged, this might not be earthshaking,
but it tells us something significant. California lilacs don't grow
in coastal sage scrub, the dominant plant community in the Laguna
Greenbelt. Although there are shrubs with white flowers elsewhere in
the Greenbelt, they're very different plants, and they don't bloom at
this time of year.
To find the typical plant community where California lilacs grow,
you have to go inland and to higher elevations, like the Santa Ana
Mountains or Riverside County. If you're driving to the desert for
spring wildflowers this month, you start to see a few bushes with
blue flowers along Highway 91 in Santa Ana Canyon, and later they
show up as you climb towards Cajon Pass on Highway 15. There, the
roadside plant community is chaparral, another scrub community, but
quite unlike our coastal sage.
So why are those lilacs growing in South Laguna? They tell us that
something is different about the hillsides there.
Vegetation in South Laguna lives under conditions that are quite
unlike the rest of Laguna. For starters, the bedrock is not our usual
pale yellow sandstone, but a darker, harder, grey rock full of chunks
of other rocks, called San Onofre Breccia (pronounced brech-ia). When
it weathers to small particles it helps produce a soil with special
characteristics. The unusual soil and a special local climate that
includes winds bearing seeds from six different directions, plus the
influence of coastal fog, yield a unique and very rare mixture of
coastal sage scrub, inland chaparral (where the lilacs come from) and
coastal Baja plants. This southern maritime chaparral community
exists nowhere else in Orange County and is one of the rarest natural
communities in California.
Now is about the right time to look up at the South Laguna
hillsides and savor the sight of those white lilacs. Afterwards,
Coast Wilderness Park and make your own discoveries. In matters
botanical, as in so much of life, "Vive la difference!"
* ELISABETH M. BROWN is a biologist and the president of Laguna