Delaware Code
Subchapter VII. Projects Requiring Landscape and Reforestation Activities
§ 211. Planting standards.

(a) All landscaping and planting activities undertaken as part of the Department of Transportation's obligation to mitigate the removal, cutting or clearing of landscape improvements pursuant to this part must be conducted pursuant to a landscape plan prepared by the Delaware licensed and registered landscape design professional or by the Delaware Department of Transportation, and must be conducted:

(1) To promote transplant survival;
(2) In compliance with federal law and regulation;
(3) In compliance with any Department of Transportation design specifications relating to obstructions in the right-of-way, and the distance that landscape improvements must be planted from the travel lanes of the roadway for safety purposes and corresponding to any policies related to context sensitive design;
(4) In compliance with the Department of Transportation's landscape and reforestation policies developed in conjunction with the Department of Agriculture and the Department of Natural Resources and Environmental Control or other such public or private agencies as the Department of Transportation may deem appropriate; and
(5) To be maintainable with resources available to the Department at the time of planting, to include any permanent agreements entered into relating to maintenance.
(b) A landscape plan prepared by a Delaware-licensed and registered landscape design professional or by the Delaware Department of Transportation for use in completing the minimum landscaping and planting activities required by this part may include whatever components the Department of Transportation determines are necessary or appropriate for the area in which the activities will take place, but must at a minimum:

(1) Screen, while maintaining transportation safety standards, at least 50 percent of the frontage of industrial properties and the back sides of nonagricultural, commercial properties;
(2) Use an appropriate combination of trees, shrubs, groundcovers, and grass or sod, both within median areas and along all roads, for aesthetic and screen purposes; and
(3) Select from upper, medium and lower canopy trees, both within median areas and along all roads where space is safely available, that:

a. Are no less than 1 inch in diameter, as measured 6 inches above the established ground level when planted;
b. Are planted in sufficient quantities to achieve an aesthetically pleasing view and/or, if outside the right-of-way, wildlife habitat when fully grown.
(c) All landscaping and screening shall be in conformance with any context sensitive design and vegetative policies that are in effect at the time of the project.
(d) No landscape improvement determined to be an invasive species shall ever be knowingly planted, authorized or required by the Department of Transportation.