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Mowing and Tree Trimming

Mowing & Brush Cutting

Seasonal mowing is performed by highway maintenance crews with tractor/mower units between three (3) to four (4) times per year between May 1 and November 1 to improve safety and aesthetics. Approximately 6,000 acres of County-maintained right of ways are cut /mowed annually (The DPW&T cuts approximately 2/3 (or 867 lane miles) of the 1,300 lane miles within the County highways maintenance system. The balance of the lane miles are within subdivisions which are usually address by the residents).When hand mowing, safety shoes, goggles, and ear protection and other personal protective equipment (PPE) are required to be worn.Approximately eight (8) tractor mowers and two boom-axes (approximately 10 staff members / 25% county highways staff) are dedicated to mowing operations during the mowing season. It takes road crews an estimated 8 weeks to make a single pass. As mowing crews finish in their dedicated areas, they are diverted to assist other crews in competing their assigned routes. In certain areas such as grass median islands (ie. FDR and Pegg Road), contractor support may be utilized to provide additional assistance, subject to funding.

Another area of importance is the maintenance of our road right-of-ways. We have an obligation to preserve clear sight lines on our roadways for the safety of our motorists and pedestrians. This task includes the removal of brush and tree limbs that protrude into the road easement. This vegetation can prevent motorists from seeing traffic signs and can also interfere with their ability to see pedestrians. We also mow roadside ditches starting in the Spring to prevent the over growth of these areas with weeds. We mow again in the fall as part of our preparation for snow removal. By keeping the vegetation mowed short the wind can blow the snow across the roadway. If the grass is allowed to remain tall it acts as a snow fence. This causes the snow to deposit on the road creating slippery spots when vehicles traveling over the snow pack it down.

Noxious Weeds

Any herbicide application requires the County to have a Maryland Department of Agriculture (MDA) Certified Pesticide Applicator qualified to perform the work. There is a need to spray herbicides in areas adjacent to guardrails and around posts / sign standards where mowing operations are restricted and manpower is not available to repeatedly return to the same location. The Department obtained its formal individual certifications, in June 1998, to perform this activity. The State performs all other regulated activities. The St. Mary's County Weed Control Program is a cooperative program with the MDA that provides spraying of noxious weeds in the road right-of-ways. Weeds that are sprayed include Thistle, Johnsongrass and Shattercane along approximately thirty (30) County-maintained roadways. In order to provide supplemental funding for this Program, the County maintains an MDA Noxious Weed Control Grant Agreement. The terms of the Agreement extend between July 1 and May 31 each year. The Department of Public Works provides all chemicals (minimum of 5 gallons of Roundup Pro) per year and the Program provides the required supervision, technical support and the spray truck for the spraying operations. A list of locations is provided by the MDA each year. A Pesticide Public Agency Permit (No. 26548) and Public Agency Applicator Certificate (No. 25648 -15648) are renewed on June 30th each year.

Safety First

Employees are trained (or re-training) in and familiar with safety related work practices and safety procedures. The DPW&T is required to certify that their employees have received such training. Proper supervision and on-site inspections further ensure that our employees remain proficient in these operations. Provisions for medical services and first aid, conducting job briefings prior to beginning work, use of personal protective equipment and inspection of critical safety components of mechanical equipment before each use are all part of placing safety of the employees, "first".

Within the four Highway Maintenance Service Districts, problem areas are identified and prioritized for action by the Manager into manageable segments of the roadway. Zone "A" is the area within the roadside shoulders (disturbed by mowing, berm removal, and snow plowing) and is the most intensively managed each year for safety to ensure guardrails, guard posts, signs, other structures, and the presence of the ditch-line is not concealed. Zone "B" is managed for safety in terms of sight distance so that wildlife does not hide and then wander onto the roadway or attempt to cross without warning. It is also managed for drainage, water infiltration, and erosion control every three to five years on an as needed basis and extends from the edge of shoulder a distance of ten feet (10'). Zone "C" extends from the edge of Zone B to the edge of the existing right of way or prescriptive maintenance easement and has the least amount of maintenance activity.

Tree Trimming

Trees are trimmed year-round to remove deadwood, diseased branches, structural defects and to train the growth of young trees and is required for public safety. Trees are also trimmed to maintain adequate clearance for vehicles, cyclists and pedestrians generally 12-14' over the road and 80" over the sidewalk. The Annotated Code of Maryland states that the height of a vehicle and its load may not exceed 13'-6''. Branches obscuring visibility for motorists, pedestrians, traffic signals, stop signs and other traffic control devices are also removed through the use of bucket trucks. "Trimming" may include the removal of vegetation on private property that encroaches into the public right-of-ways. Trees are also trimmed by the various utility companies, most commonly to minimize problems caused by branches rubbing on energized lines. This activity is not regulated by the County. Requests to remove a tree from the public right of way should be made to the Division of County Highways. Upon inspection, the work needed, if any, is prioritized based on the severity of the work needed. That work which has the greatest potential to adversely affect public safety receives the highest priority. The highest priority items are assigned to crews first. In addition, mechanical brush cutting is performed between January 1st and May 1st each year.


In accordance with COMAR Title 08, Subtitle 07, Chapter 02 requirements the Department of Public Works & Transportation maintains a Public Agency Tree Maintenance Permit from the Maryland Department of Natural Resources. This permit does not cover the removal of any trees, which do not pose an imminent hazard and must be renewed annually. The permit is very specific as to the work activities allowed and any deviations must be approved by the Regional Urban Forester. The Highway Maintenance Division has numerous individuals who maintain a Certificate of Registration as Maryland Department of Natural Resources Forest Service Roadside Tree Care Experts. The Department has received its annual Public Agency Tree Maintenance Permit, RTPA No. 2001S1, from the Department of Natural Resources Maryland Forest Service which is valid through December 31, each year, at which time it needs to be renewed.


Trees outside the County-maintained right of way, State protected trees (cedar, red-bud, dogwood & holly), and ornamental trees of specified height and caliper require separate individual permit processing through the Forester regardless of their condition or threat to the public.

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