General Planting Procedures for Landscape Work

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Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.


We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.



  1. This specification provides guidance for excavating for and planting new trees, shrubs and groundcover, seeding new lawns, preparing and applying soil amendments, and providing initial maintenance of landscape materials.

  2. When planning for or evaluating landscaping around historic buildings, it is sometimes possible to obtain original landscaping plans in the original drawings.

    1. Such drawings may be available at the building, GSA Regional Office or National Archives.

    2. Such plans, where they exist, typically identify all plantings and their quantities and location.


  1. AmericanHort. The American Standard for Nursery Stock (ANSI Z-60.1-2014). Columbus, Ohio: American Horticulture Industry Association, 2014.

  2. Kelsey, Harlan P., Dayton, William A. Standardized Plant Names. 2nd ed. J. Horace McFarland for the American Joint Committee on Horticultural Nomenclature, 1942.


  1. Design Data/Test Reports/Certificates:

    1. Soils test: Furnish Architect with written soils analysis by recognized laboratory made in accordance with methods established by the Association of Official Agriculture Chemists. Soils analysis shall include recommendations for any changes to specified soil amendments that are deemed necessary as a result of the soils test.

    2. Plant and Material Certifications:

      1. Certificates of Inspection as required by governmental authorities.

      2. Manufacturer's or vendor's certified analysis for soil amendments and fertilizer materials.

      3. Labels substantiating that plants, trees, shrubs and planting materials comply with specified requirements.

      4. Seed vendor's certified statement for each grass seed mixture required, stating botanical and common name, percentages by weight, and percentages of purity, germination, and weed seed for each grass seed species.

    3. Test Reports: Provide report on topsoil analysis from approved testing sources:

  1. Operation and Maintenance Data:

    1. Provide typewritten maintenance instructions for the continuing care of installed plants through the full growing season.

    2. Instructions should convey procedures to be established by Owner for maintenance of landscape work for one full year.

    3. Submit maintenance instructions prior to expiration of required maintenance period(s).


Subcontract landscape work to a single firm specializing in landscape work.


  1. Packing and Shipping:

    1. Deliver packaged materials in containers showing weight, analysis, and name of manufacturer.

    2. Protect materials from deterioration during delivery, and while stored at site.

  2. Acceptance at Site:

    1. Provide freshly dug trees and shrubs.

    2. Do not prune prior to delivery unless otherwise approved by Architect.

    3. Do not bend or bind-tie trees or shrubs in such manner as to damage bard, break branches, or destroy natural shape.

    4. Provide protective covering during delivery.

    5. Do not drop stock during delivery.

  3. Storage and Protection:

    1. Deliver trees and shrubs after preparations for planting have been completed and plant immediately. If planting is delayed more than 6 hours after delivery, set trees and shrubs in shade, protect from weather and mechanical damage, and keep roots moist by covering with mulch, burlap or other acceptable means of retaining moisture.

    2. Do not remove container-grown stock from containers until planting time.


Existing Conditions:

  1. Utilities: Determine location of underground utilities and perform work in a manner which will avoid possible damage. Hand excavate, as required. Maintain grade stakes set by others until removal is mutually agreed upon by parties concerned.

  2. Water Supply: Verify extent of on-site availability and location for this work and conditions of use with the government.

  3. Excavation: When conditions detrimental to plant growth are encountered, such as rubble fill, adverse drainage conditions, or obstructions, notify Architect before planting.


  1. Planting Time:

    1. Proceed with complete landscape work as rapidly as possible, working within seasonal limitations for each kind of landscape work required.

    2. Schedule a specified maintenance period following date of substantial completion.

  2. Coordination with Lawns:

    1. Plant trees and shrubs after final grades are established and prior to planting of lawns, unless otherwise acceptable to Architect.

    2. If planting of trees and shrubs occurs after lawn work, protect lawn areas and promptly repair damage to lawns resulting from planting operations.


  1. Warranty lawns, trees and shrubs through specified maintenance periods, and until final acceptance.

  2. Remove and replace trees, shrubs, or other plants found to be dead or in unhealthy condition during warranty period.

    1. Make replacements during growth season following end of warranty period.

    2. Replace trees and shrubs which are in doubtful condition at end of warranty period; unless, in opinion of Contracting Officer, it is advisable to extend warranty period of a full growing season.

  3. Another warranty inspection will be conducted at end of extended warranty period, if any, to determine acceptance or rejection.

  4. Only one replacement (per tree, shrub or plant) will be required at end of warranty period, except for losses or replacements due to failure to comply with specified requirements.

  5. Whenever observed by the Contractor or notified by the Contracting Officer, the Contractor shall immediately correct unsatisfactory conditions at no added cost to the Government. This shall include damage to the buildings and ground resulting from these Contractor activities.


  1. Begin maintenance immediately after planting.

  2. Maintain trees, shrubs, and other plants until final acceptance, but in no case, less than 60 days after substantial completion of planting.

  3. Maintain trees, shrubs, and other plants by pruning, cultivating, and weeding as required for healthy growth.

    1. Restore planting saucers.

    2. Tighten and repair stake and guy supports and reset trees and shrubs to proper grades or vertical position as required.

    3. Restore or replace damaged wrappings.

    4. Spray as required to keep trees and shrubs free of insects and disease.

    5. Water trees, plants and groundcover beds within the first 24 hours of initial planting and not less than two times per week (including rain) until acceptance.

  4. Maintain lawns for not less than the period stated below, and longer as required to establish an acceptable lawn.

  5. Maintain lawns by watering, fertilizing, weeding, moving, trimming, and other operations such as rolling, regrading and replanting as required to establish a smooth, acceptable lawn, free of eroded or bare areas.

  6. Upon completion of the maintenance period and prior to final inspection, all lawn areas shall be fertilized by the contractor with post-planting commercial fertilizer (16-6-8) at the rate of 6 lbs. per 1,000 square feet.

  7. The Contractor shall be responsible for a period of one year after completion of plant installation to maintain all planting and work incidental thereto by replanting, plant replacements, watering, weeding, cultivating, fertilizing, pruning, controlling insects and diseases, maintaining guy wire and by performing all other operations of care for promotion of root growth and plant life so that all work is in a continuing satisfactory condition throughout the maintenance period.

  8. All planting and plant materials required by this Contract shall be in a condition acceptable to the Contracting Officer at the end of the maintenance period.

  9. The Contractor shall replace any planted trees that are dead, or are in an unhealthy or unsightly condition or have lost their natural shape, or both, due to dead branches, excessive pruning, inadequate or improper maintenance, within the warranty period. However, replacement shall be made during the next planting season, after the need becomes apparent, notwithstanding that such planting season may run beyond either the maintenance period or the warranty period.



  1. Topsoil: Topsoil will be protected in place for re-use in landscape work. If quantity of stockpile topsoil is insufficient, provide additional topsoil as required to complete landscape work.

  2. Soil Amendments:

    1. Sawdust: Neutralized fir or redwood shavings, free of chips, stones, sticks, soil, or toxic substances and with 7.5 pounds of nitrogen uniformly mixed into each cubic yard of sawdust.

      1. Particle size, dry weight basis: percent passing sieve size 95-100 1/4" mesh 0-3 no. 40 mesh

      2. Organic content: 94% as determined by ash analysis

      3. Chemistry: Minimum 0.8% nitrogen and 0.8% dilute acid soluble iron based on dry weight. Salinity shall not exceed 2.5 millions per centimeter as measured in the saturation extract.

    2. Commercial Fertilizer: Complete fertilizer of neutral character, with some elements derived from organic sources and containing the following percentages of available plant nutrients:

      1. Pre-Planting: Provide fertilizer with not less than 6% total nitrogen, 20% available phosphoric acid, and 20% soluble potash.

      2. Planting Tablets: Tightly compressed, long- lasting, slow release fertilizer tablets manufactured expressly for placing in the root zone of plants and providing not less than 20% total nitrogen, 10% available phosphoric acid, and 5% soluble potash.

      3. Post-Planting: Provide fertilizer with no less than the percentages of total nitrogen, available phosphoric acid, and soluble potash indicated. Provide nitrogen in a form that will be available to lawn during initial period of growth; at least 50% of nitrogen to be organic form.

    3. Peat: Shall be a Federal Specification Q-P-166 domestic product. Moss peat shall be horticultural grade (fine shreds). Reed-sedge is not acceptable.

    4. Bone Meal: Finely ground, having a minimum analysis of four percent nitrogen and 20% phosphoric acid, delivered in unopened bags showing weight, analysis and manufacturer's name, shall be stored in weatherproof storage place and in such a manner that its effectiveness will not be impaired.

    5. Agricultural Gypsum: Commercially packaged powder form, calcium sulfate dihydrate at 95% minimum by volume.

    6. Soil Sulfur: Minimum 98% elemental sulfur.

    7. Iron Supplement: Iron sulphate, long lasting, pelletized, and shall contain the following minimum available percentages by weight: nitrogen 1%, iron 12%, zinc 1%, total combined sulfur 17%, sulfate sulfur 7%, calcium 3%, magnesium 1.5%, cobalt .004%, copper .06%.

  1. Plant Materials:

    1. Quality: Provide trees, shrubs, and other plants of size, genus, species, and variety shown and scheduled for landscape work and complying with recommendations and requirements of "The American Standard for Nursery Stock" (2014).

    2. Deciduous Trees: Provide trees of height and caliper scheduled or shown and with branching configuration recommendation by "The American Standard for Nursery Stock" for type and species required.

      1. Provide single stem trees except where special forms are shown or listed.

      2. Container-grown deciduous trees will be required subject to specified limitations of "The American Standard for Nursery Stock" for container stock.

    1. Deciduous Shrubs: Provide shrubs of the height specified by architect and with not less than minimum number of canes required by "The American Standard for Nursery Stock" for type and height of shrub required.

      • Container-grown deciduous shrubs will be required subject to specified limitations for container grown stock.

    1. Coniferous and Broad-Leaf Evergreens: Provide evergreens of sizes specified by architect. Provide normal quality evergreens with well-balanced form complying with requirements for other size relationships to the primary dimension shown.

      • Container-grown evergreens will be required subject to specified limitation for container grown stock.

    1. Grass Seed: Provide fresh, clean, new-crop seed complying with tolerance for purity and germination established by Official Seed Analysts of North America. Provide seed mixture composed of grass species, proportions and minimum percentages of purity, germination, and maximum percentage of weed seed, as specified.

  1. Ground Cover: Provide plants established and well-rooted in removable containers or integral peat pots and with no less than minimum number and length of runners required by "The American Standard for Nursery Stock" for the pot size shown or listed.

  2. Miscellaneous Landscape Materials:

    1. Wood Headers and Edging

      1. Of sizes shown and following wood species.

      2. All Heart Redwood.

      3. Provide wood stakes of the same species, 2" by 2" by 24" long and with galvanized nails for anchoring headers and edging.

    2. Mulch: Organic mulch free from deleterious materials and suitable for top dressing of trees, shrubs, or plants and consisting of fir bark chips, medium texture.

    3. Stakes and Guys:

      1. Provide stakes and deadmen of sound new hardwood, treated softwood, or redwood, free of knot holes and other defects.

      2. Provide wire ties and guys of 2-strand, twisted, pliable galvanized iron wire, not lighter than 12 gallons, with zinc-coated turnbuckles.

      3. Use tree ties to protect tree trunks from damage by wires.

    4. Wrapping Material:

      1. Shall be 8- 10 inch width two-ply bituminous laminated crepe paper strips.

      2. Tying twine shall be a lightly tarred medium or coarse sisal yarn at top and bottom.

    5. Anti-Desiccants:

      1. Shall be sprayable, water insoluble vinyl-vinylidene complex which will produce a moisture retarding barrier not removable by rain or snow.

      2. The resultant film when applied shall have a moisture vapor transmittance rate of not more than 10 grams per 24 hours at 70% humidity.

      3. Evidence shall be furnished that the material meets these requirements and is safe for both deciduous and evergreen plants before any application shall be made.

    6. Polystyrene Board Insulation: Closed-cell expanded polystyrene beads molded into rigid insulation boards complying with FS HH-I 524, Type I, Class A, 8.0 psi compressive strength, 2.5% maximum water absorption and 1-1/2" thick.

    7. Metal Pipe Liner: AASHTO Designation M245-78; Precoated, Galvanized Steel Culverts and Underdrains; Type I Pipe.


  1. Tests/Inspection:

    1. Inspection of Growing Site:

      1. The Contracting Officer reserves the right to inspect and select by tagging plant materials before delivery from the growing sites. This does not preclude the right of rejection at the project site.

      2. Provide the Contracting Officer the proposed delivery schedule dates sufficiently in advance to allow for these inspections.

    2. Testing: Provide tests and report of topsoil proposed for use. These shall be by the local State Agricultural Experiment Station or any agricultural laboratory recommended by the US Department of Agriculture.

    3. Inspection: The Architect may inspect trees and shrubs either at place of growth or at site before planting, for compliance with requirements for genus, species, variety, size, and quality. Architect retains right to further inspect trees and shrubs for size and condition of balls and root system, insects, injuries and latent defects, and to reject unsatisfactory or defective material at any time during progress of work. Remove rejected trees or shrubs immediately from project site.

  2. Verification of Performance:

    1. General:

      1. Ship landscape materials with certificates of inspection required by governing authorities.

      2. Comply with regulations applicable to landscape materials.

    2. Do not make substitutions. If specified material is not obtainable, submit proof of non-availability to Architect, together with proposal for use of equivalent material.

    3. Analysis and Standards:

      1. Package standard products with manufacturer's certified analysis.

      2. For other materials, provide analysis by recognized laboratory made in accordance with methods established by the Association of Official Agriculture Chemists, wherever applicable.

    4. Trees, Shrubs and Plants:

      1. Provide trees, shrubs, and plants of quantity, size, genus, species, and variety shown and scheduled for landscape work and complying with recommendations and requirements of "The American Standard for Nursery Stock".

      2. Provide healthy, vigorous stock, grown in recognized nursery in accordance with good horticultural practice and free of disease, insects, eggs, larvae, and defects such as knots, sun-scald, injuries, abrasions, or disfigurement.

    5. Label at least one tree and one shrub of each variety with a securely attached waterproof tag bearing legible designation of botanical and common name.

    6. Where formal arrangements or consecutive order of trees or shrubs are shown, select stock for uniform height and spread, and label with number to assure symmetry in planting.

    7. Supply Source:

      1. Prior to bidding, verify sources of supply to insure that all plants shown, of the sizes, species, variety and quality required can be supplied.

      2. Failure to provide may result in the Contracting Officer obtaining the items and the Contractor being held liable for these costs in accordance with the Contract requirements.



  1. General:

    1. Lay out individual tree and shrub locations and areas for multiple plantings.

    2. Stake location and outline areas and secure Architect's acceptance before start of planting work.

    3. Make minor adjustments as may be required.

  2. Preparation of Planting Soil:

    1. Before mixing, clean existing soil of roots, plants, sods, stones, clay lumps, and other extraneous materials harmful or toxic to plant growth.

    2. Mix specified soil amendments and fertilizers with existing soil at rates specified. Delay mixing of fertilizer if planting will not follow placing soil within a few days.

    3. For pit and trench type backfill, mix planting soil prior to backfilling, and stockpile at site.

    4. For planting beds and lawns, apply amendments on surface of soil and mix thoroughly before planting.

  3. Preparation for Planting Areas and Lawns:

    1. Prior to preparation of unchanged areas, remove existing grass, vegetation and turf. Dispose of such material outside of Owner's property. Do not turn existing vegetation over into soil being prepared for planting.

    1. Preparation of Unchanged Grades: Where areas are to be planted that have not been altered or disturbed by excavating, grading, or stripping operations, prepare soil for planting as follows:

      1. Till to a depth of not less than 6 inches.

      2. Apply soil amendments and initial fertilizers as specified.

      3. Remove high areas and fill in depressions.

      4. Till soil to a homogenous mixture of fine texture, free of lumps, clods, stones, roots and other extraneous manner.

    2. Fine-grade areas to smooth, even surface with loose, uniformly fine texture.

      1. Roll, rake, and drag planting areas, remove ridges and fill depressions, as required to meet finish grades.

      2. Limit fine grading to areas which can be planted immediately after grading.

    3. Moisten prepared planting areas before planting if soil is dry. Water thoroughly and allow moisture to dry before planting. Do not create a muddy soil condition.

    4. Restore planting areas to specified condition, if eroded or otherwise disturbed, after fine grading and prior to planting.


  1. Excavation for Trees and Shrubs:

    1. Excavate pits, beds, and trenches with vertical sides and with bottom of excavation slightly raised at center to provide proper drainage.

      1. Loosen hard subsoil in bottom of excavation.

      2. For all trees and shrubs, make excavations at least half again as wide as the ball diameter and equal to the ball depth.

    1. Dispose of subsoil removed from planting excavations. Do not mix with planting soil or use as backfill.

    2. Fill excavations for trees and shrubs with water and allow water to percolate out prior to planting.

  2. Planting Trees and Shrubs:

    1. All plants shall have planting tablets placed three inches below grade at the following rates during planting:

      1. (2) - 21 gram tablets per each one gallon plant.

      2. (4) - 21 gram tablets per each five gallon plant.

      3. (6) - 21 gram tablets per each fifteen gallon plant.

      4. (1) - 21 gram tablet per each linear four inches boxed material size.

    2. Set stock in planting hole, plumb and in center of pit or trench with top of ball at same elevation as adjacent finished landscape grades.

    3. When stock is set, place additional backfill around base and sides of ball, and work each layer to settle backfill and eliminate voids and air pockets.

      1. When excavation is approximately 2/3 full, water thoroughly before placing remainder of backfill. Repeat watering until no more is absorbed.

      2. Water again after placing final layer of backfill.

    4. Set container grown stock, as specified; cut cans on two sides with an approved can cutter; remove bottoms of wooden boxes after partial backfilling so as not to damage root balls.

    5. Saucer the top of backfill to provide room for mulching.

    6. Mulch pits, trenches, and planted areas. Provide no less than two inches of mulch, and work into top of backfill and finish level with adjacent finish grades.

    7. Prune, thin out, and shape trees and shrubs in accordance with standard horticultural practice.

      1. Prune trees to retain required height and spread.

      2. Unless otherwise directed by Contracting Officer, do not cut tree leaders, and remove only injured or dead branches from flowering trees, if any.

      3. Prune shrubs to retain natural character.

      4. Remove and replace excessively pruned or malformed stock resulting from improper pruning.

    8. Guy and stake trees immediately after planting, as indicated.

    9. After all plants are installed, broadcast all planting areas (excluding lawn areas) with post-planting commercial fertilizer (12-12-12) at the rate of 8 lbs. per one thousand square feet.

  3. Seeding New Lawns:

    1. Do not use wet seed or seed that is moldy or otherwise damaged in transit or storage.

    2. Sow seed using a spreader or seeding machine. Do not seed when wind velocity exceeds 5 miles per hour. Distribute seed evenly over entire area by sowing equal quantity in two directions at right angles to each other.

    3. Sow not less than the quantity of seed specified or scheduled.

    4. Rake seed lightly into top 1/8 inch of soil, roll lightly, and water with a fine spray.

    5. Broadcast all lawn areas with post-planting commercial fertilizer (16-6-8) at the rate of 6 pounds per 1000 square feet after lawn seed installation, in addition to the fertilizer called for in soil preparation in this specification.