As internationally-recognized leaders in the sustainable landscaping movement, Owen Dell and Associates, LLC is at the forefront of proactive change. We constantly strive to reduce the negative environmental impacts of our work and to be sure our actions are consistent with our philosophy. Wherever it is practical to do so, the following standards will be applied to your project unless you wish us to do otherwise. We realize that although landscaping has many positive benefits, there are still unavoidable negative consequences. We will make every effort to reduce those, now and in the future.


Here are the standards we use in designing projects and which we require contractors and others related to the project to uphold. This is a brief summary of a much larger set of guidelines. Please look them over. We welcome any suggestions for improvements. 


WOOD PRODUCTS Use certified sustainably harvested lumber and wood products exclusively when they are available. Provide a copy of the certification for all materials delivered to the site. Advise if certified materials will not be used for part or all of the project. Suggest alternatives such as recycled plastic lumber, salvaged lumber or wood harvested from urban trees.

STONE PRODUCTS Do not harvest materials from intact natural ecosystems. Obtain boulders and paving stone from responsible sources. Protect watersheds and streams when harvesting materials.

IMPORTED SOIL Do not obtain soil from natural areas. To the degree possible, ensure that suppliers protect against erosion and other environmental damage in the course of their operations, and that the product is free of toxins and non-degradable rubbish.

FERTILIZERS All fertilizers must be made from 100% non-chemical sources, i.e. “organic” fertilizers. Pre-approved brands include Gro-Power, Dr. Earth, Whitney Farms. Others are acceptable if authorized prior to bidding. Read labels carefully to be sure of content.

PESTICIDES No pesticides not listed as OMRI-approved shall be used on any project without prior authorization.

HERBICIDES Minimize the use of glyphosate-based and other non-organic approved herbicides. Where practicable, use alternative methods of weed control such as hand weeding, grubbing, heat treatment, sheet mulching, or alternative herbicides. Inquire prior to bidding about specific weed control specifications for each project.

AMENDMENTS AND OTHER ORGANIC MATERIALS Purchase organic materials from responsible sources. Do not use materials that are contaminated with noticeable quantities of non-degradable rubbish, detectable chemicals, etc.

PLANTS To the degree possible, obtain plants from nurseries that practice integrated pest management and protect air, soil and watersheds from pollution. Do not dig plants from the wild or purchase wild-harvested plant materials.


REFUSE DISPOSAL Dispose of all refuse in an approved facility. Recycle all greenwaste, broken concrete, asphalt and wood products in an approved manner. Reuse materials such as drip tubing, lumber cutoffs, etc. whenever possible. Where applicable, leave chipped organic material on site to be used as mulch.

SLOPES When working on slopes, take whatever precautions are necessary to prevent erosion and siltation of waterways. These may include appropriate grading practices, use of erosion control fabrics, soil binding agents, approved cover crops, drainage systems, silt fences, and other practices agreed upon in advance of bidding.

WATERWAYS Protect all streams and creeks from damage. Do not allow employees to use streams as bathrooms. Always provide portable toilets where other facilities are not available.

EXISTING VEGETATION Protect from damage all existing vegetation that is to remain, including damage to the root zone. Do not park vehicles or equipment, or store heavy materials within the root zone of trees. Locate all staging areas away from trees. Do not trench within the dripline of any mature tree without prior approval. Where necessary, install protective fencing at the dripline of mature trees. Do not prune existing plants without prior approval.

SITE MANAGEMENT Do not store hazardous materials on site. Maintain a clean site at all times during the project.

IRRIGATION Do not allow any irrigation within at least 8 feet of the trunk of any native oak tree. Do not allow any irrigation system to overspray planted areas or to generate significant spray drift or runoff. Include in all bids two follow-up visits to reprogram controller/s and modify watering schedule as required by maturing plantings and seasonal changes.

NOISE CONTROL Minimize use of power equipment. Operate noisy equipment within community guidelines as to hours of operation. No radios are allowed on any jobsite.

DUST CONTROL Blowers are not to be used unless approved in advance. Practice approved standard dust control techniques during grading and earth-moving operations. Operate off-road equipment at slow speeds to avoid raising dust.

AIR POLLUTION Minimize the use of diesel or gasoline-driven power equipment (chainsaws, tillers, weed-eaters, etc.). Do not disable any required emission control devices on power equipment or vehicles. Use electric or hand tools where it is not cost-prohibitive. Do not use any product containing volatile organic compounds (pesticides, oil-based paints, other petroleum-based products) without prior approval.

WORKER’S RIGHTS Comply fully with all legally-required fair employment practices, including OSHA standards, federal anti-discrimination laws and all federal, state and local employee laws and regulations. Provide a workplace that is safe for workers, clients and others. Pay all workers a living wage.