Why do wildflowers grow where they do?
By Conservancy Science Director Mike White
Most people are interested in when wildflowers are going to bloom, but a closer look at where they bloom is just as interesting. First a little wildflower Ecology 101. The wildflowers at Tejon can be divided into two broad categories: annuals and perennials (bulbs). In the Mediterranean climate of California, winter rains trigger germination of annual wildflower seeds in the soil, which grow into mature plants that flower, set seed, die, and drop their seeds into the soil which wait for the next rainy season.
Annual plants get all of their water and nutrients from the soil they grow in and the water it holds, and they survive the dry season or drought years by remaining as a seed in the soil. Perennial plants on the other hand, remain alive through the dry season with an underground bulb or tuber that stores water and nutrients. The bulbs send out leaves after the onset of winter rains and then a flower stalk that sets seeds, which fall to the ground the same way an annual’s do. However, bulbs can also propagate themselves by dividing – budding off bulblets. Like annuals, perennials rely on water and nutrients in the soil, but unlike annuals, they have their own underground storage structure, which helps them survive when conditions for growth and flowering are not appropriate. Being an annual plant or a perennial with an underground storage structure are adaptations that allow these plants to thrive in environments with uncertain amounts of rainfall. Why do we care about all of this? Because when these plants thrive, we get wildflowers!
So back to why wildflowers grow where they do. While wildflowers get their water and nutrients from the soil, the amount of water and nutrients depends on the type of soil and where it is located (for example its elevation or amount of rainfall, slope and aspect, the direction the slope faces). Different species of wildflowers are adapted differently to these environmental conditions. For example, our grassland/rangeland research has shown that different “communities” of plants (a community is a group of species that tend to co-occur) can be found in distinct Ecological Sites on Tejon. An Ecological Site is an area of land that has a unique combination of physical features that create unique environments for plants.
Plant communities that are dominated by different wildflower species create the mosaic of colors that we see painted across the landscape, and that mosaic is a product of the weather and underlying environmental variation that occurs across a landscape such as Tejon. As a preview of what we might expect in this year’s wildflower show, we share a few of these communities for your enjoyment.
California goldfields, here with California poppies, can carpet sandy desert soils. Also found in this community is one of the few native annual grasses that occur on Tejon, small fescue (Festuca microstachys).
California poppies, sky lupine, and popcorn flowers are common in relatively flat sandy areas of the San Joaquin Valley.
Yellow hillside daisies and purple phacelias are clay soil lovers in the Antelope Valley. This is a unique community of plants found on clay soils derived from ancient lakebed deposits.
California poppies and coreopsis cover slopes with sandy soils derived from these eroding granite boulders.
Common goldenstar, a relative of the lily family, is common across a range of habitats including valley grassland, oak woodland and yellow pine forest.
Goldenstars (top) and brodiea are perennial bulbs that grow together in clay soils, often with nonnative annual grasses.
Blue dicks (a perennial) and the rare Tejon poppy (an annual) on the unique Pleito clay soils of the Tejon Hills.
Buttercups (yellow), blue-eyed grass (purple), and death Camas (white) are all perennials found in a unique marsh habitat in the Antelope Valley. Note a different community of yellow hillside daisies and California poppies on the slopes in the background.
A day of pipe capping on Tejon Ranch
On Sunday, February 26th, twenty volunteers joined the Conservancy to cap over 160 open pipes on a corral adjacent to both oak woodlands and a large Eucalyptus grove teeming with a diverse community of birds.
The Audubon Society and several agencies including USFWS, BLM, and NRCS have advocated for capping open-topped pipes due to their potential to kill wildlife by entrapping birds, lizards, and small mammals.
Photos by Conservancy Volunteer Chris Gardner.
Many thanks to the stupendous volunteers who donated their Sunday to helping conserve the wildlife on Tejon Ranch!