Hedgerows Protect California Vineyards

Federal cost-share programs help grapegrowers attract beneficial insects

by Jon Tourney
Jeanette Wrysinski of the Yolo County Resource Conservation District discusses hedgerow site planning and installation near this roadside hedgerow of native trees and shrubs at Oakdale Ranch in Yolo County. Photo by: Jon Tourney
Esparto, Calif.—California farms and vineyards have been planting and maintaining more hedgerows in recent years as a result of increased interest in sustainable farming operations; available expertise and financial assistance from conservation agencies, and better knowledge about hedgerow uses and benefits. A workshop Sept. 8 in Yolo County focused on insectary hedgerows for pollinators and beneficial insects. The 80 attendees, representing a wide range of farming operations and products, learned that hedgerows provide multiple agricultural and environmental benefits.

The workshop was organized and presented by entities that assist farmers and landowners to plan and install hedgerows: the Yolo County Resource Conservation District (RCD), the USDA Natural Resources Conservation Service (NRCS), The Xerces Society for Invertebrate Conservation and the University of California Cooperative Extension (UCCE). Commercial native plant nurseries and consultants Cornflower Farms Inc. of Elk Grove, and Hedgerow Farms of Winters, also presented information.

Yolo County has been proactive in hedgerow and resource conservation projects in recent years. Heather Nichols-Crowell of the Yolo County RCD said projects planned for this winter will add 10,000 linear feet of hedgerows in the county.

Hedgerows for beneficial insects

UCCE Yolo County farm advisor Rachael Long provided an overview of the benefits of hedgerows, based on her 20 years of experience and research. She has written papers about establishing hedgerows for agricultural operations and their ability to enhance beneficial insect populations.

“Hedgerows are rows of trees, shrubs, forbs and perennial grasses that border or surround farm fields. They are extremely beneficial for a number of reasons that include enhanced weed control, air and water quality protection, soil erosion control, increased biodiversity with wildlife habitat—and they enhance beneficial insect populations that serve as pollinators or provide natural enemy activity on pests in adjacent crops,” Long explained.

The workshop emphasized use of native flowering plants to attract beneficial insects: Long listed California native species such as coffeeberry, elderberry, buckwheat, and toyon as plants that attract parasitic wasps.

She observed, “A lot of beneficial insects need nectar and pollen from flowering plants in order to survive and reproduce.” Long’s research has monitored populations of beneficial insects in hedgerows and tracked their movement into adjacent commercial crops. One study monitored beneficial insect populations in a commercial crop: It indicated that 25% of the lacewings, 25% of the ladybird beetles and 45% of the parasitic wasps had come from an adjacent hedgerow. “Insects are using these floral hedgerows, then are moving into crops,” Long said.

Hedgerows also can harbor smaller populations of insect pests, she said, but beneficials far outnumber the pests. In contrast, uncontrolled weeds can harbor twice as many pests as beneficials. Replacing weedy areas with hedgerows and native plants not only enhances beneficial insect populations, it can also be more effective than continual spraying or discing for weed control in hard-to-farm locations.

“Hedgerows help prevent spray drift and dust movement from farm operations,” Long pointed out. “We get a higher number of beneficials in farm fields if we have hedgerows, and I believe if we had more hedgerows, we would have a higher and more significant effect.” She noted that studies are needed to determine the economic value of hedgerows in terms of what they contribute to pest control for farms.

Planning and developing hedgerows
Jeanette Wrysinski of the Yolo County RCD discussed site selection, planning, installation and maintenance of hedgerows. For site selection, Wrysinski advised, “Look at all of your weedy, unused areas; look at the edges of the farm. These are the primary spaces to install native plants and hedgerows.”

Sites may include non-cropped areas along roadsides, agricultural drains, fences, canals and field borders with different elevations. Specific site conditions should be considered, such as soil moisture and condition (avoid sites that flood), access to water to establish plants, traffic from vehicles and farm equipment and space for the size of mature plants. “Take advantage of resources and expertise,” Wrysinski advised. “Many entities, such as RCDs and NRCS don’t charge for consulting and planning advice,” she said.

Overall goals including habitat and insectary issues and the adjacent crop will influence site and plant selection. The landowner’s visual and esthetic goals regarding color and height, also will influence plant selection.

Weed control at the hedgerow site should begin at least one year before planting, with discing and spraying. In California, planting is done in fall or winter, preferably after rain has provided some soil moisture content. Growers commonly install drip irrigation to get new plants established; output emitters are based on each plant’s needs.

Native grasses and forbs can be established quickly to help with weed control and provide flowering plants the first season. Large trees and shrubs are planted 10 to 15 feet apart, small shrubs 7 to 8 feet apart. Plant protectors such as grow tubes or milk cartons are recommended.

Maintenance should be done for at least the first three years, for weed control and to allow native plants to establish. Wrysinski advised placing signs at planted sites—the Yolo RCD makes and sells these—that read “no discing, no spraying” in English and Spanish, so field workers don’t damage young hedgerows by mistake.

Promoting pollinators
Jessa Guisse of The Xerces Society discussed creating habitat for native bees, and the bees’ role in crop production. She said, “About 70% of the world’s flowering plants require a pollinator, and one-third of all the food we eat requires pollination.”

She discussed honeybee population decline in North America. The species was introduced from Europe to pollinate commercial crops. Guisse observed, “Native bees contribute to commercial crop pollination, but are not as recognized for their role as honeybees.”

Because grapes are self-pollinating, attracting pollinators may be less of a concern for grapegrowers, but pollinators can help with vineyard cover crop species by enabling them to produce viable seeds each year. In addition, flowering hedgerows in vineyards can provide sanctuary for pollinators, mitigate population losses of bees and provide credit for growers in sustainable and organic certification programs. 

Taylor Lewis of Cornflower Farms, which grows native plants for wholesale nurseries, and restoration and hedgerow projects throughout California, discussed specific flowering plants for native bees and beneficial insects. A mixed planting of the right native shrubs and grasses can provide blooming flowers for beneficial insects year round.  

The workshop convened at the 400-acre Oakdale Ranch, a diversified farming operation dating to 1850 that now includes walnut orchards, corn and seasonal row crops.

The first of two hedgerow projects on display is a row of native trees and shrubs along an access road. It provides benefits for weed control, soil erosion prevention and habitat for beneficial insects and birds. Valley oak, coyotebush, California rose, California box elder, western redbud, ceanothus and coffeeberry are planted here.

Second was the South Fork Willow Slough Restoration Project—a drainage ditch was cleared of invasive weeds, the channel was widened and improved; the banks were replanted with native riparian trees and vegetation to improve drainage and water quality, and provide wildlife and beneficial insect habitat.

NRCS cost-share programs
Ha Truong, agricultural engineer with the NRCS in Yolo County, said the agency provides free technical services and consultation to farmers and landowners nationwide. NRCS has cost-share financial assistance programs for habitat restoration and improvements, including hedgerow installation projects.

The Environmental Quality Incentive Program (EQIP) was established in the 1996 Farm Bill and reauthorized in the 2008 Farm Bill. An EQIP focus is specialty crop producers, including grapegrowers, to help plan and implement sustainable conservation practices that address soil erosion, air and water quality, plant and animal habitat and energy conservation.

NRCS organic farming programs are also available to assist producers in transitioning to organic practices. Although growers can generally apply for cost-share financial assistance at any time, Truong noted that Nov. 18 is the final day to apply for project funding for the 2012 fiscal year. Growers should contact their local NRCS office for technical assistance and program information. (See the national website for local office locations.)

Littorai looks at hedgerows
Littorai Wines (5,000 cases) of Sebastopol, Sonoma County, was represented at the workshop by John Wilson, who manages the 30-acre winery estate property that includes a 3-acre Pinot Noir vineyard. The estate is a Biodynamically farmed, diversified and integrated operation. Wilson was looking for information to plant a hedgerow on the coastal side of the farm property to serve as a windbreak and to provide habitat for beneficial insects.

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