This publication summarizes the steps involved in establishing hedgerows on farms in California and concludes with a discussion of potential food safety issues associated with hedgerows and attracting wildlife to farms. Farm Plan When considering habitat restoration work on farms it is important for landowners to develop a whole farm plan to integrate their conservation goals and methods with current farming operations. Examples of habitat restoration goals include the use of hedgerows for soil erosion reduction, wildlife enhancement, increasing biodiversity, water and air quality protection, windbreaks, attracting beneficial insects for pest control and bees for pollination in adjacent crops, and weed control. The goals of the restoration work will affect the types of plants selected and where the project should be established on the farm. Consult an aerial map of the farmland to assess the topography, hydrology and drainage, crop production areas, non-crop areas, and buildings before defining the appropriate use of the land for different types of restoration purposes. Also consider potential funding sources, since restoration projects can be expensive. A good source of information for cost-share programs and additional farm plans is your local Natural Resources Conservation Service as well as the Yolo Resource Conservation District , Robins et al. 2001, and CAFF 2004. Site Selection Once a farm plan has been developed, select sites for the proposed work. The most suitable areas for restoration projects include non-cropped areas along roadsides, agricultural drains, fences, canals, marijuana grow system field borders with different elevations, and gullies. Sites should be easily accessible by equipment for project construction and maintenance. Access to water during the growing season is essential for establishment of shrubs and trees for at least the first 3 years or until the plants are well rooted to survive California’s long, dry summers.

Site Analysis After selecting a site for a hedgerow, analyze the area to determine which design and plants would perform best. Some hedgerows fail because the plants used are not well adapted to the local field site conditions. Determine the soil type, assess the area for potential flooding, and identify obstructions such as overhead wires that would limit tree planting. High and low spots that have standing water should also be noted, as well as potential for plant injury from nearby livestock, or competition from established vegetation such as shading from trees, equipment traffic, and herbicide drift. Planning and Design Once the site has been analyzed, make a drawing of the area that shows the size of the restoration project, types of plants to be incorporated in the design, and the planting layout. In general, linear plantings are the easiest to maintain with the large-scale equipment such as mowers, disks, or sprayers commonly used on farms. A single strip of shrubs and/or trees bordered by strips of native perennial grasses, and/or sedges and rushes if riparian, and a forb strip works well as a hedgerow design on field crop farms . Access roads separating the hedgerow from the crop help prevent birds from feeding on newly emerged crop seedlings, which may occur when native grasses and shrubs are planted adjacent to the crop.Figure 1 shows a typical plant spacing for trees, shrubs, and forbs. In mixed perennial plantings one grass type may initially dominate the stand, but over time other species will begin to emerge. In addition to the forbs listed above, the forb strip seed mix can include lupines , clovers , tarweeds , vinegar weed , and California poppy . Additional trees include oaks , California sycamore , and California buckeye . A more complete list of plants and perennial grasses adapted to various regions in California and information on where to purchase them can be obtained from the Resource Guide for Hedgerows in California and the Pictorial Guide to California Native Grasses . For large-scale plantings of shrubs and trees, place orders at least 6 months in advance to ensure plant availability.

Site Preparation and Planting Hedgerow sites should be disked and shaped to prepare the area for planting, providing a good seedbed for the native perennial grasses and forb seed mix. Although the grass seed can be planted into ground that has not been recently worked using a no-till drill, weed control will become more difficult and costly later on. Some hedgerows are planted flat, others on raised 60-inch beds. If the site is flood-irrigated and soils are heavy with a high water-holding capacity, use only plants that tolerate flooding. Space the larger shrubs at a 15-foot spacing and the smaller ones in between the large ones at 7.5 feet . Trees need a 20- to 30-foot spacing, depending on the variety. Fertilize the shrubs and trees with compost or a slow-release fertilizer at recommended rates at time of planting. Plant the native perennial grasses at 12 to 14 pounds per acre and the forb strip at 15 to 20 pounds per acre. Use a no-till drill for the native grasses because the long awns on some varieties tend to get stuck in the drills. Sometimes a carrier such as bran may need to be added to the seed mix to achieve this low planting rate. Perennial grass seed can also be broadcast at 20 to 25 pounds per acre, and forbs at 20 to 30 pounds per acre, then lightly harrowed by dragging a chain across the site to cover the seed. The best time to plant perennials in California is in the fall when cooler and wetter conditions help plants establish before the summer heat sets in. Irrigate every 1 or 2 weeks during the growing season for the first 3 years, or until the plants are well rooted. The duration and frequency of the irrigations will depend on plant evapotranspiration rates and soil type. So, for example, plants in sandier soils on hot days will need more frequent watering than those in heavier clay soils with a high moisture-holding capacity. After 3 years, the hedgerow plants will still benefit from an occasional summer watering. In areas lacking access to water, water tanks can be used with pumps to pressurize and deliver the water through drip lines. Native perennial grasses and many direct-seeded forbs go dormant in the summer and do not need to be irrigated.

Bird herbivory on new forb seedlings can be prevented by the use of bird scare tape on poles and netting. Weed Management Weed control is the most difficult and challenging part of establishing hedgerows of native grasses, trees, and shrubs on farms. For hedgerows of shrubs and trees , the most cost effective and long-term solution for weed control is to use mulches, such as walnut shells or compost, or weed mats. Preemergence herbicides such as Ronstar can be used, but they may not provide enough broad-spectrum weed control. That is, several weeds may be controlled, but others often take their place. Roundup provides effective weed control, but drift to nearby hedgerow plants must be prevented when spraying,especially when the plants are small. Once the hedgerow plants establish, they will help shade out competing weeds. For establishing native perennial grasses and forb strips, let the winter rains bring up the first flush of winter weeds prior to planting; control these by harrowing or spraying with Roundup. A second application of Roundup can be made about a week after planting to help control the faster growing annual weeds before the perennial grasses emerge . Walk the area to make sure the native grasses have not emerged prior to spraying with Roundup or you will lose the stand. These may be difficult to identify so if you are not sure, either skip the Roundup spray or call someone with experience in native grass plantings for help in identifying the seedlings. If drill-seeded, look for rows of seedlings. For broadleaf weed control in native grasses a number of herbicides can be used, including the phenoxys MCPA and 2,4-D, curing and drying weed as well as Buctril , Garlon , Milestone , and Vista . Be sure to check with your local agricultural commissioner for restrictions on the use of these materials, especially with the phenoxys that cannot be used after March 1 in many counties. These herbicides may also injure newly emerging native grass seedlings, so wait until the grasses are at least several inches tall before applying them. Grass weeds in native perennial grass stands are difficult to control. Preemergence herbicides do not give a broad enough spectrum of annual grass weed control, and there are no registered postemergence herbicides that can be used in mixed native grass stands without injuring them. To help the perennial grasses compete, mow annual grasses in the spring before the weeds set seed during the first 2 years of stand establishment. Weed whacking, weed wicking, and spot spraying with herbicides will also help maintain a healthy stand. Burning the native grasses in the fall helps control weeds, but do not burn on a hot day or the native grasses will be injured. Be careful as well not to burn the native shrubs, which can be injured or killed by fire. More information on weed control can be obtained through the University of California Gophers and voles will feed on the roots and crowns of establishing shrubs and trees, sometimes causing extensive plant losses. To prevent vole damage, place plastic tree tubes around plants at the time of planting to keep the rodents from girdling them. In severe vole outbreak years, apply zinc phosphide, diphacinone, or treated grain to control these pests. These rodenticides are available through some county agricultural commissioner offices. Follow the label carefully to avoid poisoning non-target species such as birds. Monitor and trap for gophers when activity is observed. Poison baits are also available for gopher control. Barn owl boxes can also be placed in the hedgerows to attract owls that prey on these rodents.Once established, hedgerows of shrubs, trees, sedges, and native perennial grasses compete fairly well with weeds, but they still require yearly maintenance to keep weeds under control. Grasses should be mowed, grazed, or burned every couple of years to maintain the health of the stand, with the timing and frequency dependent on the weed complex and severity in the stand. In general a good time to mow established grasses is after July, when the bird-nesting season is over. Monitor shrubs and tree plantings yearly for rodents and weeds, as weedy hedgerows tend to attract insect and rodent pests that may cause problems for adjacent crops. Established hedgerows of shrubs and trees may also benefit from an occasional summer watering, especially during drought years.The cost of establishing a hedgerow for the first 3 years is estimated to be $3,847 for a 1,000-foot-long hedgerow with a single row of shrubs and trees bordered by native perennial grasses . This cost includes labor for site analysis and design and field preparation, including disking and shaping the site and preparing a seedbed. The cost also includes plants, seed mixes, fertilizers, and labor for planting. Weed control costs include mulches, herbicides, and hand-hoeing; although high initially, these costs will decline as the native perennial grasses and shrubs mature and outcompete weeds. Irrigation costs include drip tube and emitters as well as labor for installing the system and irrigating the plants for at least 3 years. Vertebrate pest control costs include tree tubes to protect young plants from voles and squirrels, rodenticides, and trapping. Additional costs to manage the hedgerow will be incurred beyond 3 years, but these costs should be minimal, consisting of mowing or spot treatments with herbicides and the occasional watering during the summer or drought years. NRCS cost-share programs are available to help plant hedgerows on farms, covering from 50 to 75 percent of the costs, depending on the program and hedgerow type.Outbreaks of the food pathogens Escherichia coli O157:H7 in leafy green vegetables, as well as outbreaks of serovars of Salmonella enterica in nut crops, have prompted a variety of preharvest food safety concerns about management practices including establishing wildlife habitat and related potential vector attractants to farms. These concerns are largely focused on raw horticultural foods. Although various types of E. coli naturally occur in many animals , research indicates that domestic cattle are the primary reservoir of toxin-forming pathogens such as E. coli O157:H7 associated with foodborne illnesses.