Conservation Buffers in Organic Systems: Oregon Implementation Guide

The purpose of this document is to provide guidance in installing practices for use as buffers in organic production systems in order to meet the National Organic Program (NOP) regulations. Conservation buffers are generally strips of vegetation placed in the landscape to influence ecological processes and provide a variety of services.

Conservation Buffers in
Organic Systems
Oregon Implementation Guide

March 2014
National Center for
Appropriate Technology (NCAT)
Oregon Tilth
Xerces Society

Purpose…………………………………………….. 3
Table 1.
Primary and Secondary
Benefits of Buffer-Related Practices….. 4
Buffer Site Design……………………………… 5
Site Preparation………………………………… 6
Table 2.
Weed Management Options…………….. 7
Short-Term Maintenance and
Planting Considerations………………….. 10
Long-Term Maintenance
of Buffers…………………………………………. 11

Figure 2. This hedgerow protects the adjacent crop from dust and reduces the risk
of dust-induced mite infestations.

Appendix A.
Seed Suppliers and Plant Lists ……….. 12
Appendix B.
Classes of Organic Herbicides…………. 13
Appendix C.
References………………………………………. 14

Funded by a grant from
Western Sustainable
Agriculture Research
and Education (WSARE).

Copyright © NCAT and Oregon Tilth 2014

Authors Rex Dufour, (National Center for Appropriate Technology NCAT); Sarah Brown, Ben Bowell and Carrie Sendak
(Oregon Tilth); Jennifer Miller (Northwest Center for Alternatives to Pesticides); Mace Vaughan, Eric Mader, Jessa Guisse,
Jolie Goldenetz Dollar, and Brianna Borders (Xerces Society)
Reviewers Giulio Ferruzzi, Thad Heater, Dean P. Moberg, Albert Mulder, and Loren St. John (Natural Resources Conservation Service); Gwendolyn Ellen (Oregon State University); Jennifer Reische (Clackamas Soil & Water Conservation
District); Richard Straight (USDA National Agroforestry Center)
Design and layout Karen Van Epen (NCAT)
Photos Rex Dufour (NCAT) unless otherwise noted.
Figure 1. (front cover) Four-year-old demonstration hedgerow with ninebark and checker mallow at the USDA NRCS
Plant Materials Center, Corvallis, Oregon. The hedgerow is a collaborative project of the Xerces Society, the Farmscaping
for Beneficials Program at Oregon State University and the NRCS Plant Materials Center.
Photo: Gwendolyn Ellen, Oregon State University, 2011.
For more information or questions, contact Ben Bowell at or 503-580-4767


The purpose of this document is to provide guidance
in installing practices for use as buffers in organic
production systems in order to meet the National
Organic Program (NOP) regulations. Conservation
buffers are generally strips of vegetation placed in the
landscape to influence ecological processes and provide
a variety of services. They are called by many names
including wildlife corridors, greenways, windbreaks,
and filter strips. (Bentrup, G. 2008)
In the context of organically managed systems, buffer
zones are required under NOP rules if there is a risk
of contamination, via drift or flow, of substances not
allowed under organic regulations. Situations in which
buffers will likely be required by the certifier, according
to NOP rules, include:
➣ An organic field bordering a conventional field on
which prohibited substances are being used.
➣ An organic field bordering a roadway to which prohibited substances are applied (usually to control weeds).
➣ An organic field bordering residential housing in
which prohibited substances are being applied.
➣ An organic field that has, or is immediately adjacent
to, fencing made of lumber treated with prohibited
When buffers are required in organic production systems,
they represent an opportunity to implement conservation
practices that benefit the operation by creating habitat
for beneficial organisms (birds, pollinators, or parasites
and predators of crop pests), as well as providing a barrier
against weed seed migration, preventing wind damage to
crops and protecting water quality. In doing so, buffers
may simultaneously meet other NOP regulations which
require that organic operations “maintain or improve the
natural resources of the operation” (NOP Sec 205.200)

and, in perennial systems, can be used to introduce
biological diversity in lieu of crop rotation.
According to the NOP, buffer zones between organic
crops and non-organic crops must be of sufficient size
and structure to prevent drift or runoff of non-approved
substances. Although there are no specific size requirements, typically a buffer zone is 25- to 30-feet wide. The
organic producer can grow non-organic crops in the
buffer zone, leave it fallow, or plant this area to hedgerows,
windbreaks, meadows, or beetle banks, as appropriate.
If a crop is taken from the buffer zone it will need to
be harvested separately from the organic crop and the
producer must document that it was harvested, stored,
and sold as non-organic.
If the organic certifying agency has determined that a
buffer is needed, they must also approve the design of
the buffer. NRCS staff can work with the landowner to
identify additional conservation objectives for the buffer
(see Table 1), which may include habitat for parasitoids
and predators of crop pests, reducing soil erosion,
protecting water quality, wind or dust breaks, habitat
and cover for other wildlife including pollinators, and
aesthetic considerations.
Hedgerow Planting (422) is a focus of this document
as this practice can readily address NOP requirements.
However, buffers may be created on organic operations
using other NRCS conservation practices, such as
Field Borders (386), Herbaceous Wind Barriers (603),
Windbreak/Shelterbelt Establishment (380), Riparian
Forest Buffer (391), Filter Strip (393), Riparian Herbaceous Cover (390) or Conservation Cover (327). All of
these practices can be designed to have multiple benefits
for the operation.

Relevant National Organic Program (NOP) Regulations
Section 205.202 Land Requirements

Section 205.2 Definition of Buffer Zone

Any field or farm parcel from which harvested crops
are intended to be sold, labeled, or represented as
“organic,” must:
(c) Have distinct, defined boundaries and buffer zones
such as runoff diversions to prevent the unintended
application of a prohibited substance to the crop or
contact with a prohibited substance applied to adjoining
land that is not under organic management.

An area located between a certified production operation
or portion of a production operation and an adjacent land
area that is not maintained under organic management.
A buffer zone must be sufficient in size or other features
(e.g., windbreaks or a diversion ditch) to prevent the
possibility of unintended contact by prohibited
substances applied to adjacent land areas with an
area that is part of a certified operation.


Table 1.

Primary and Secondary Benefits of Buffer-Related Practices

NRCS Practice
and Definition

Primary Benefits/Functions of Practice

Secondary Benefits /
Functions of Practice

Field Borders (386) Strips of
permanent vegetation
established at the edge or
around the perimeter of a

➣ Reduce erosion from wind and water.
➣ Protect soil and water quality.

➣ Manage pest populations.
➣ Provide wildlife food and cover.
➣ Provide food, shelter and overwintering sites for
beneficial invertebrates as a component of
integrated pest management.

Hedgerow Planting (422)
Establishment of dense
vegetation in a linear design
to achieve a natural resource
conservation purpose.

➣ Habitat, including food, cover, and corridors for
terrestrial wildlife.
➣ Enhance pollen, nectar, and nesting habitat for
➣ Provide food, shelter and overwintering sites for
predaceous and beneficial invertebrates as a
component of integrated pest management.
➣ Intercept airborne particulate matter.
➣ Reduce chemical drift and odor movement.
➣ Create screens and barriers to noise and dust.

➣ Create food, cover, and shade for aquatic
organisms that live in adjacent streams
or watercourses.
➣ Increase carbon storage in biomass and soils.
➣ Create living fences.
➣ Delineate boundaries & contour guidelines.
➣ Prevent weed seed migration into the field.

Herbaceous Wind Barriers
(603) Herbaceous vegetation
established in rows or narrow
strips in the field across the
prevailing wind direction.

➣ Reduce soil erosion from wind.
➣ Reduce soil particulate emissions to the air.
➣ Protect growing crops from damage by wind or
wind-borne soil particles.

➣ Enhance snow deposition to increase
plant-available moisture.

Establishment (380)
Linear plantings of single
or multiple rows of trees or
shrubs or sets of linear

Riparian Forest Buffer (391)
An area of predominantly
trees and shrubs located
adjacent to and up-gradient
from watercourses or water

➣ Create shade to lower water temperatures to improve
habitat for fish and other aquatic organisms.
➣ Create wildlife habitat and establish wildlife
➣ Reduce excess amounts of sediment, organic material,
nutrients, pesticides and other pollutants in surface
runoff and in shallow ground water flow.
➣ Provide protection against scour erosion within the
➣ Restore natural riparian plant communities.

➣ Provide a source of detritus and large woody
debris for fish and other aquatic organisms and
riparian habitat and corridors for wildlife.
➣ Moderate winter temperatures to reduce
freezing of aquatic over-wintering habitats.
➣ Increase carbon storage in plant biomass and
➣ Provide a harvestable crop of timber, fiber,
forage, fruit, or other crops consistent with
other intended purposes.

Riparian Herbaceous Cover
(390) Herbaceous vegetation
tolerant of intermittent
flooding or saturated soils that
is established or managed in
the transitional zone between
terrestrial and aquatic habitats.

➣ Provide food, shelter, shading substrate, habitat and
pathways for movement by aquatic, semi-aquatic and
terrestrial organisms.
➣ Improve and protect water quality by reducing the
amount of sediment and other pollutants in surface
runoff and in shallow ground water flow.
➣ Help stabilize stream bank and shorelines.
➣ Increase net carbon storage.

➣ Provide food, shelter and overwintering sites
for beneficial invertebrates such as insect
predators, parasitoids and native pollinators for
IPM and crop pollination.

Conservation Cover (327)
Establishing and maintaining
permanent vegetative cover.
This land is removed from
production permanently for
the life of the contract.

➣ Reduce soil erosion and sedimentation.
➣ Improve water quality.
➣ Enhance habitat for wildlife, predacious insect
invertebrates, and pollinators.
➣ Improve soil quality.
➣ Stabilize slopes.

➣ Improve air quality.
➣ Manage crop pests.
➣ Provide better access to agricultural equipment
when soils are moist.


Reduce wind erosion.
Protect growing plants.
Provide shelter for structures and livestock.
Provide wildlife habitat.
Improve irrigation efficiency.

➣ Manage snow.
➣ Provide a tree or shrub product.
➣ Provide noise and visual screens.
➣ Enhance aesthetics.
➣ Increase carbon storage.
➣ Delineate property and field boundaries.
➣ Prevent weed seed migration into the field.
➣ Provide food, shelter and overwintering sites
for beneficial invertebrates such as insect
predators, parasitoids and native pollinators for
IPM and crop pollination.

Note: All primary benefits and the majority of secondary benefits are taken directly from NRCS practice standards.
A few secondary benefits were added by reviewers of this document.

Buffer Site Design
Site Selection
➣ Location: The overall design of a buffer site must meet

NRCS practice criteria as well as the standards of the
producer’s certifying agency and the National Organic
Program. To address NOP buffer requirements, the site
selected should be adjacent to an area from which there
is a risk of contamination from pesticides or chemical
fertilizers not allowed in organic systems. This is commonly along property lines, but in situations where the
producer has both organic and conventional operations,
the buffer could be in the middle of an operation at the
boundary between the two types of production.
➣ Width and height: The site selected for the buffer
should be wide enough and have space for plants to
grow tall enough to intercept any significant pesticide
drift from the adjacent conventional operation.

➣ Irrigation access: The site should also have access to

irrigation water to establish the plants and, in drier
areas, address long-term water needs. Drip irrigation
works well for plugs or potted plants. For native grasses
and wildflower mixes that are broadcast, planting
should be done during the rainy season, with back-up
sprinkler irrigation.
➣ Soils: Soil type will influence the plants that will
thrive in an area. Amending planting holes with good
quality compost also improves growth rate.
➣ Sunlight: Most native perennial shrubs, forbs, and
grasses do best in locations with full sunlight. Plants,
however, should be selected based on the site conditions
and some varieties thrive in shade.
➣ Accessibility: The site should be accessible to equipment
for site preparation, planting and maintenance.

Plant Selection
The choice of plants for a buffer will vary based on
goals and objectives of the producer and site limitations.
Many potential goals are listed as benefits in Table 1 and
include habitat creation, erosion reduction and water
quality protection.
➣ Pesticide drift mitigation: If the objective is pesticide
drift mitigation to address NOP requirements, buffer
plants should be selected to provide enough height,
leaf area, and structural diversity to intercept anticipated
contamination, especially pesticide drift, from adjacent conventionally managed land. For buffers with
a high risk of frequent exposure to insecticides, the
buffer should have approximately 40-50% porosity
in multiple rows to allow the wind to go through the
trees—not up and over—and ensure droplets are
captured by the leaves. The design of a buffer should
focus on leafy canopy (e.g., evergreen, conifers, and
small needles) rather than nectar and pollen resources
of beneficial insects. For design details, see Windbreaks
Designed with Pollinators in Mind, listed in Appendix
C. The method of pesticide application (e.g., aerial
application via plane or application by back-pack
sprayer) will also be factored in by the certifying
agency when determining the size and structure of a
buffer zone.

➣ Pollinators and beneficials: If the landowner’s goal

is to provide habitat for beneficials, then the design
should focus on providing year-round nectar and pollen
resources as well as nesting and overwintering habitat.
Native plants often provide the greatest benefit.
➣ Planting stock: As crops in the buffer cannot be
sold as certified organic, producers are not required to
use certified organic seeds and planting stock. Seeds,
however, must not be treated with non-approved
synthetic substances to prevent contamination of
the adjacent organic crops. Producers should always
check with their certifier before planting or applying
anything new on their operation.
➣ Runoff filtration: A mixture of perennial grasses and
forbs can be established for this purpose. The more
diverse the vegetation, the more effective the buffer will
be at slowing down the run-off and allowing the soil
and roots to absorb it. For riparian areas, adding trees
and shrubs to a buffer may also provide shade to cool
the water in support of desirable aquatic organisms,
and habitat for birds and other terrestrial organisms.
➣ Seeding wildflowers: Wildflowers can be planted
from seed within or adjacent to hedgerows to provide
plant structure and diversity. Seeding requires excellent
site preparation to reduce weed pressure since weed
control options are limited when the wildflowers start

Plant Selection, continued
to germinate. For more information on establishing
wildflowers from seed, see Conservation Cover (327)
for Pollinators: Specifications and Implementation
Requirements, listed in Appendix C. Transplanting
may improve chances of establishment, but will be
more expensive than seeds.
➣ Multiple functions: Grasses, forbs, shrubs, and trees
have different functions and characteristics within
the ecosystem and understanding these will allow
the landowner to better design a buffer to meet their
objectives. In most situations, buffers designed to
meet a grower’s primary objective(s) can also meet
several secondary objectives by including two or more
of these groups of plants. For example, the dense root
systems of perennial grasses are ideal for filter strips,
but adding forbs creates a more diverse filter strip
which can provide habitat for beneficial insects and is
more resilient to seasonal variations in weather.
Adding shrubs and trees further diversifies buffer

structure. Use of different plant types should be
evaluated based on the landowner’s objectives and
resource concerns, which might include: aesthetic
value; bloom time; flower shape, size, and duration
of bloom (in support of predators, parasites and
pollinators); nesting and perch habitat for birds and
raptors; use as windbreaks and road dust barriers;
ditch stabilization or revegetation; or providing shade
for stream cooling and fish habitat.
➣ Plant growth and development: The buffer zone’s
interaction with adjacent crops is dynamic and will
change with time. Plants in the buffer zone will
increase in size and change the ecology of the area by
providing shade, wind protection, new micro-climates,
new habitat including overwintering habitat, and new
food sources such as nectar, pollen, berries, seeds, fruit,
and alternative prey. Deer may browse on buffer zone
plants, as well as crops; rabbits, ground squirrels and
rodents may take advantage of buffer zone habitat.

Site Preparation
Site preparation is one of the most important
components to successfully establishing a buffer. On
an organic operation this can present a unique set of
challenges since chemical herbicides are generally not
allowed. Competition from weeds can envelop a poorly
prepped site, killing off many of the buffer plants (see
Figure 7). Investing time—in many cases an entire
growing season—and effort in creating a well prepared
buffer planting site will pay off in lower maintenance
and plant replacement costs, and a better growth and
establishment rate for the buffer plants. The focus of site
preparation in the buffer area should be:

In areas with poor drainage or high rainfall, planting on
raised beds or berms could be used to address issues of
wet soils in a buffer. Most native perennials will flourish
in a well-drained environment. Or select wetland plant
species adapted to such conditions which would provide
benefits to wetland-dependent wildlife species.
Site preparation weed management options are provided
in Table 2 and largely focus on trees and shrubs used to
meet NOP buffer requirements. Pictures of proper site
preparation and maintenance are provided on the
following pages.

➣ Reduce the weed seed bank in the top soil layers
➣ Eliminate all perennial weeds
➣ Avoid disturbing the soil after the weed seed

bank and weed pressure are reduced.

Resources for Buffer Design
Xerces Society for Invertebrate Conservation.
Pollinator Habitat Installation Guides

Conservation Buffers: Design Guidelines for
Buffers, Corridors, and Greenways. Bentrup, G.
2008. Gen. Tech. Rep. SRS-109. Asheville, NC.
Department of Agriculture, Forest Service, Southern
Research Station. 110 p.

Table 2. Weed Management Options
METHOD: Stale Seedbed
Where to Use:
➣ Where weed pressure is low to moderate
➣ Total time: Four to six weeks
➣ Areas with a low risk of erosion
➣ Begin: Any time
➣ Areas accessible to equipment
➣ Plant: Fall or early spring
Basic Instructions:
1. This can be done in various combinations: Tillage-Irrigation-Light Tillage-Mulch, or Tillage-IrrigationFlaming-Mulch, or Tillage-Irrigation-Organic Herbicide-Mulch
2. Where weed pressure is low, till the existing vegetation for the length and width of the hedgerow.
3. Irrigate with sprinklers or natural rainfall.
4. To kill emerging weeds, do very shallow tillage (Lilliston or harrow), or use flame weeders or organic
herbicides. It’s critical to flame or herbicide the weeds when they’re small (2 to 3 inches) to kill them.
Use of an organic herbicide might require multiple applications.
5. Mulch with weed barrier cloth, weed-seed-free straw mulch, wood chips, or other materials.
Organic Herbicides: Herbicides approved for use in organic systems are generally much less effective than
conventional herbicides such as glyphosate. Organic herbicides are most effective when used on small
plants (1 to 3 inches). See Appendix B for more information about types of organic herbicides.
Mulches: Weed barrier cloth is very effective in suppressing weeds, but does not allow for ground-nesting
native bees or other beneficial invertebrates to tunnel in the soil. When it is used in a cropped area, the NOP
stipulates that synthetic mulch must be removed at the end of the season. Buffers are generally considered
non-cropped areas, unless crops are produced in the buffer zone. In some cases burlap is used as a long-term
substitute for synthetic materials. Care should be taken in the selection of mulches in riparian areas as they
can be washed into waterways. Organic mulches of straw, wood chips and other materials can be effective
weed barriers, and once these materials degrade, ground-nesting bees are able to access the soil surface.
A six-inch layer of straw mulch will generally last only one season.
METHOD: Smother Cropping
Where to Use:
➣ Where weed pressure is low to moderate
➣ Areas with a low risk of erosion
➣ Areas accessible to equipment

➣ Total time: One to three months
➣ Begin: Summer
➣ Plant: Generally quick-growing summer cover
crops are used and planted once temperatures
have warmed enough in the spring or summer.
➣ Smother crop method may be used prior to
use of stale seedbed in the spring or summer

Basic Instructions:
1. Select quick-growing crops appropriate for the site. Buckwheat, millets, and sorghum-sudan
grasses are usually best. Clovers are too slow to effectively compete with weeds and legumes will
fix unnecessary nitrogen.
2. Seed into prepped bed immediately after finished working the soil; use a seeding rate 1.5 to 3 times the
normal rate to create an effective smother crop more quickly.
3. Once mature, incorporate the cover crop while minimizing soil disturbance.
4. Ideally follow smother crop with appropriate version of Stale Seedbed technique described above.


METHOD: Solarization
Where to Use:
➣ Where weed pressure is moderate to high
➣ Begin: Works best during mid-summer
➣ Areas with a low risk of erosion
➣ Plant: Fall or winter
➣ Areas accessible to tillage equipment
➣ Timing will vary between 4 and 8 weeks
➣ Locations with full sun, warm weather,
depending on sun intensity and temperature
and dry summers
during solarization
Basic Instructions:
1. Mow, rake, harrow, or till and smooth the site in the spring, raking off debris, if necessary.
2. After smoothing the site, irrigate thoroughly and lay clear UV-stabilized plastic, or “regular” clear 1 ml
plastic (Molinar, R. 2013, pers. comm.), burying the edges to prevent airflow between the plastic and
the ground. Check with your local extension service for which plastic they recommend. Weigh down
the center of the plastic if necessary to prevent the wind from lifting it. Use greenhouse repair tape for
any rips that occur during the season.
3. Remove the plastic in early fall (remember that non-UV stabilized plastic, although less expensive than
UV-stabalized plastic, will disintegrate if left too long in the sun) and immediately install transplants. Refer
to the Planting Considerations section of this document for specific bed-preparation recommendations.
4. Once the plastic is removed, avoid disturbing the soil as much as possible because disturbances bring
viable weed seed to the surface.
“Regular” Plastic vs. UV-Stabilized (UVS) Plastic: UVS plastic is much more expensive than “regular”
clear plastic, and is only needed if the farmer intends to keep the plastic on the ground beyond 5 – 6
weeks. In hotter areas, 1 ml of clear plastic (non-UV stabilized) can provide excellent results in four weeks
if done during midsummer (mid-June to September). High tunnel greenhouse plastic can be used as a
source of UVS plastic if other sources are not available.

Site Preparation Examples
Figures 3, 4, 5, and 6 show preparation at a single location.

Figure 3. The producer started in October with a weed-free planting
bed created by disking the soil to remove weeds.


Figure 4. The same site after a January rainstorm, a couple of months
post planting.

Figure 5. The site in May, six months after planting. Weed management
was done with a combination of hand weeding and straw mulch. Note
the fruit trees in wire cages for deer protection. This grower includes
fruit trees in hedgerows for himself and the workers on the operation.

Figure 6. The site in June, three years later. Bare spots in the buffer are
still being mulched with straw.

Figure 7. This hedgerow has become overwhelmed with grass weeds.
Many of the plants succumbed to the weedy competition, even though
they had the carton protection, which helps mark the plants for
agricultural workers, and protects the young plants from wind and
sun and, to a lesser extent, from weed competition. The grower might
have been better off using a plastic weed barrier, more aggressive site
preparation, or thick mulch.

Figure 8. A two-year-old hedgerow with a plastic weed barrier mulch
has been very effective in keeping weeds from growing but prevents
perennial forbs, such as yarrow, from expanding beyond the holes
in which they were planted. The plastic weed barrier also prevents
beneficials such as ground-nesting bees, predacious ground beetles,
and spiders from accessing the soil.


Short-Term Maintenance and Planting Considerations
The more densely the buffer area is planted, the more
quickly a weed-suppressive cover will be established. This
is a cost-benefit decision, as high density plantings also
cost more due to the greater number of plants or seeds
used. Combinations of perennial trees and shrubs with
understories of native grasses and wildflowers can be used
in various ways. If seeds are used to plant the buffer (as
opposed to plugs or transplants) weed control prior to
planting must be very thorough. It is impractical to weed
the seeded area once the buffer plants germinate. It may
be worthwhile to increase the seeding rate by up to 50%
or more in order to achieve a weed-suppressive cover
more quickly. Alternatively, a focus on seeding perennial
wildflowers will allow for mowing annual weeds. Siteappropriate native plants may also aid in successful buffer
establishment because they require less water and nutrients.
Regular shovels are usually adequate for transplanting
most woody nursery stock. However, dibble sticks or
mechanical transplanters are sometimes helpful for plugplanting. Power augers and mechanical tree spades can
be helpful for larger plants. Depending on weed pressure,
hedgerow plants can be installed through planting holes
cut into landscape fabric, after which the fabric is
typically covered with mulch. While this practice may be
highly effective for weed control, it likely reduces nesting
opportunities for ground-nesting pollinators and other
wildlife. Hedgerows should be installed without, or with
minimal, landscape fabric when possible.
➣ Amendments: Most native plants are adapted to

a variety of soil conditions and do not need any
specific amendments. However, in areas where the soil
is compacted, degraded, or depleted, compost should
be used during planting. Compost should be free from
weed seeds, aged properly, and mixed thoroughly with
soil in the holes during planting. Where rodent damage
may occur, underground wire cages around roots are
recommended. Plant guards also may be needed to
protect plants from above ground browsing or antler
damage by deer. Newly planted areas should be clearly
marked to protect them from mowing and herbicides.

➣ Plant size: Consider size at maturity when planting.

Most woody shrubs can be spaced on 4- to 10-foot
centers and most herbaceous plants spaced closer on
1.5- to 3-foot centers. It is helpful to measure the planting areas prior to purchasing transplants and to stage
the transplants in the planting area prior to installing
them in the ground.


➣ Transplanting: Transplanting often occurs in the

spring, but can happen anytime the ground can
be worked. It should be timed to avoid prolonged
periods of hot, dry, or windy weather. In drier regions,
it is important to plant early to allow root growth
before the summer. Regardless of when planting
occurs, however, the transplants should be irrigated
thoroughly immediately after planting. Holes for
plants can be dug and pre-irrigated prior to planting
as well. Some woody native shrub and tree cuttings,
commonly called slips, can be planted directly into
the ground. For woody species, dormant transplants
often more successful. Specific species readily root and
can be planted in the fall before the rainy season.

➣ Irrigation: In most areas that do not receive abundant

fall and winter rains, native and drought-tolerant woody
plants should be irrigated with at least one inch of water
per week (except during natural rain events), for the first
two years after planting. Long, deep watering is best
to encourage deep root system development. Shallow
irrigation should be avoided. Drip irrigation is useful,
although it may be cost-prohibitive in large buffer areas.
Other methods that allow for deep watering can also be
successful. It is advisable to irrigate at the base of plants
and avoid overhead irrigation that would encourage weed
growth. Plugs are more amenable to drip irrigation, but
drip lines with closely spaced emitter holes can be used
for irrigation of native annuals. Once plants are established, irrigation should be removed or greatly decreased.
In areas with very little precipitation, irrigation may be
needed for the lifespan of the buffer. Non-native plants
may require more frequent irrigation, and may still
require supplemental irrigation once established.

➣ Mulching: To reduce weed competition and retain

moisture during the establishment phase, plantings
should be mulched. Recommended materials include
wood chips, bark dust, weed-free straw, nut shells,
grapeseed pomace, or other regionally appropriate
weed-free mulch materials.

➣ Mowing: Mowing is a good method to control

weeds during buffer establishment and for long-term
maintenance. Mow weeds when they are flowering
to prevent weed seed formation. Set mower height
above the establishing herbaceous buffer plants (8” or
higher) to prevent injury to them. This should be
done during a time when birds and other desirable
wildlife are not nesting. If the buffer/hedgerow has
no understory, mow close to the ground.

Long-Term Maintenance of Buffers
Buffer zones require maintenance, and the type of
maintenance depends on what has been planted and
its location. The most important maintenance considerations are irrigation, weeding, and replacing dead plants.
An important component of reducing plant mortality
in the buffer zone is making sure workers know which
plants are “keepers”. Flag or stake the plugs and transplants
so that workers can differentiate buffer zone plants from
weeds and don’t destroy them by hoe, weed-wacker,
mowing, mulching, or flaming.
➣ Irrigation: Long-term irrigation needs will vary greatly

based on geography. In drier areas native woody
plants and perennials often require two to three
years of irigation to insure their long-term survival.
Drip irrigation is usually sufficient, and longer,
deeper watering intervals will support deeper root
penetration. As stated above, in regions with very
little precipitation, irrigation may be needed for the
lifespan of the buffer. Use of overhead irrigation will
likely encourage weed growth and may interfere with
weed management practices.

➣ Weed management: As noted earlier, reducing

stressed from drought.
➣ Burning: Burning can sometimes revitalize grassy

buffers by getting rid of old thatch and providing
more space for some of the native plants. Mowing is
another way that a buffer zone can be revitalized and,
as mentioned above, both should be done in blocks to
minimize disturbance of wildlife.

➣ Replacements: W


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