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The Science of Seeding


How habitat restoration managers use science to spread native seed, and how you can help.

While hiking or out on a trail ride, have you seen colored wooden stakes and wondered what they were or how they got there? Tips of stakes can be blue, red, yellow or white, and are evidence of one of the many restoration projects being managed by the Irvine Ranch Conservancy.

The stakes represent planting done by Conservancy staff and volunteers in areas singled out for habitat restoration. In one such site, Bee Flat Canyon, the Conservancy is restoring over 80 acres of diverse habitat:  grassland, coastal sage scrub, chaparral, and oak woodland. Bee Flat Canyon is located in OC Parks’ Limestone Canyon Nature Preserve. 

Restoration efforts start by clearing invasive plants, or weeds. Conservancy staff and volunteers help to remove the weeds. After two years of growing and removing weeds the site is finally ready for planting.

In the fall, native plant seeds are prepared. “Native plant seed is expensive, which can limit how much restoration can be done,” says Habitat Restoration Project Manager Lars Higdon. “The Irvine Ranch Conservancy grows many of its seeds at its local Native Seed Farm. This helps to reduce cost and ensures availability of important species.”  

The Conservancy’s science staff considers many variables to determine which native species to plant.  Historic area photographs along with nearby land not overtaken by invasive species provide clues about which native plants will thrive. Plant seeds are mixed by hand and broken into three separate groups: shrubs, wildflowers, and grasses. Separating these different groups helps improve their success and reduces cost.

Native plants are selected for planting depending on their different growth rates. “Annual wildflowers, like California poppies, are quick to germinate, compete well with weeds, but fade away within the first couple of years,” says Higdon. “Perennial shrubs, such as coastal buckwheat, may take as long as three to four years to mature from seed but once established, cast enough shade to keep out the weeds over the long run.”  

Before seeding, stakes are placed out in rows running horizontally on the slope, and seed mixes are hand seeded into their corresponding color strip. Blue stakes are for shrubs, red for wildflowers, and yellow for native grasses. White stakes mark empty rows to allow easier access for volunteers and Irvine Ranch Conservancy Staff.

For upcoming volunteer opportunities please visit