California takes on invasives (an inside look)

Most of the plants used in gardens and landscaping do not invade or harm wildland areas. But a few species can – and do – escape from cultivated areas into open landscapes and cause a variety of ecological problems. They crowd out native plants, insects and animals, and can lead to flooding, fire and crop losses. Invasive species are a leading threat to biodiversity, second only to habitat destruction. And the economic cost is as significant as the ecological cost. In California alone, $87 million in taxpayer funds go to fighting invasive plants and animals every year.

How can the horticulture industry simultaneously serve its customers, protect wildlife and wildlands and save Californians millions of dollars? By stopping the spread of invasive plants. Industry leaders are participating in an initiative called California Horticultural Invasives Prevention (Cal-HIP) to halt introductions of invasive plants – which damage local ecosystems and are expensive to control or remove once they take hold.

Cal-HIP members are devising ways to voluntarily avoid growing, selling or promoting problem plants. Through the PlantRight campaign, the group is educating horticultural businesses about the problem and the ways they can transition to noninvasive plant material. After a year and a half of focusing on industry education, the PlantRight campaign is preparing to launch a public education effort to engage gardeners in preventing the spread of invasive plants. By timing the outreach effort in this fashion, the increase in consumer demand for noninvasive plant material will come as a support to California’s responsible, proactive businesses rather than a threat. With both the industry and the public on board, we can stop introductions of invasive plants and gradually eradicate the ones already causing problems in California wildlands.

Catalyst for change

Sustainable Conservation manages this Cal-HIP program. It is an independent nonprofit organization based in San Francisco that specializes in partnering with business sectors to find solutions to environmental problems. Sustainable Conservation’s experience with complex collaborations is ideal for managing a group like Cal-HIP, which brings together very different sectors of the plant world, including nurseries, retailers, scientists, environmental groups and government agencies.

Sustainable Conservation also raises funds to support the program. Funding includes grants from philanthropic groups like the Seaver Institute, National Fish and Wildlife Foundation, Annenberg Foundation and the Ahmanson Foundation.

Diversity counts

California is a large and ecologically diverse state. It has everything from vast mountain ranges to rich agricultural valleys to a long coastline. Each environment is home to different plants and animals -- so what is invasive in one area may not be a problem in another. PlantRight was designed to be mindful of differences in major ecological zones. Each plant was carefully analyzed to reflect its invasiveness in each of five major regions of California.

Since 2004, Cal-HIP has brought together leaders from all sectors of the horticulture industry with environmental groups, public gardens and arboreta, scientists and government agencies to collaborate and determine which invasive plants pose the greatest threats to each region.

Cal-HIP bases decisions on credible scientific research.

California Association of Nurseries and Garden Centers and other Cal-HIP partners adopted the Voluntary Codes of Conduct designed at the Missouri Botanical Gardens in 2001. These codes were created by a diverse team of nursery and landscaping professionals, scientists and environmental groups to find practical ways to avoid introducing invasive plants into the environment. Cal-HIP followed these guidelines to create a workable plan for California businesses and home gardeners to prevent invasive introductions.

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- Terri Kempton

Terri Kempton is project manager of California Horticultural Invasives Prevention (Cal-HIP); www.plantright.org.

A glance at the list

Cal-HIP reviewed plant species in the nursery causing invasive problems in the state. The group spent months analyzing data, visiting invasion sites, talking with experts and promoting research to answer remaining questions. The result is a realistic list of the top invasive species that can be prevented by removing them from the trade and replacing them with safer alternatives. Here is an abbreviated list of the plants in each region. Look at the full list on www.plantright.org.