Article

Landscapes and Vegetation


Landscapes

The first impulse in cemetery preservation efforts is usually to protect or treat the grave markers.  After all, they are the obvious historic resource.  But the condition of the stones is often indicative of a neglected landscape that is contributing to the deterioration of those historic resources.  An untended landscape with overgrown vegetation and volunteer growth can create excessive shade and detrimental microclimates, fostering biological growth and choking out grasses or ornamental plantings.  Inappropriately located paths, or paths that have inadequate widths can force pedestrians onto turf near graves, causing compaction and erosion.  Formerly gravel paths and roads, now largely paved, create new drainage patterns with higher velocity run off into undersized storm water systems.  Left unpruned, trees can grow into hazards with the potential to cause catastrophic damage to headstones and buildings during storm events.  So, while the preservation of markers should be a high priority for many cemetery managers, deteriorating stones should always be considered a symptom, not a singular disease, within the living organism that is the historic landscape. The following are some of the best practices for cemetery landscape preservation,

Pathways and Drives

While there were few of these in our early graveyards, they were an integral part of the larger landscape of the rural cemetery and later movements. The original grass or gravel surfaces were later paved with harder, impervious materials. Today it is often impractical to return to the earlier, softer, erosion-prone paving materials because of reduced staffing and budgets. It is important to maintain pavement profiles such that these routes do not collect or deter surface storm water which can lead to erosion.

Older cemeteries often do not have the generous turning radii at intersections that our contemporary vehicles require. Planned rerouting of traffic and/or provision of unobtrusive protective devices like bollards, wheel stops, or wood guardrails may be required.

Vegetation

Trees, shrubs and hedges often contribute significantly to the character of the cemetery landscape. Over time, woody plants mature and decline due to age and disease. Dead branches in specimen trees can pose threats to visitors, monuments, and structures. Proper maintenance, including pruning, integrated pest management, and periodic replacement ensures that character-defining vegetation remains a part of the cemetery. The periodic pruning of trees in historic burial places is essential to plant health and can allow light and air to reach the ground, instead of creating shaded, wet microclimates that might kill turf or foster biological growth on stones. Potentially hazardous dead wood should be removed every year, with safety pruning occurring every five years. Early removal of volunteer growth and invasive plants can prevent roots from damaging built features or crowding out historic plantings.

Plant replacements should be based on historic research, where possible, and be appropriate in terms of location, species, mature size, and maintenance requirements. The use of invasive, non-native and/or exotic plants should be avoided. Winged Euonymous (Burning Bush), a popular plant because of its striking fall color, fits into this category as it was imported from Asia in the mid-1800s and can be invasive. Substitutions or replacements should be similar in scale and character. In this case, Highbush Blueberry could be appropriate in that it also has brilliant fall color. Managers should be aware of the potential for unmarked burials when undertaking tree removals or planting projects, and an archaeological assessment may be needed.

  • Managing Gravesite Vegetation

    Managing Gravesite Vegetation

    This video is part of a series of presentations and media for people interested in learning about preservation techniques to stabilize the nation's historic gravesites. In this presentation, the Center's Chief of Historic Landscapes program, Debbie Smith, will discuss how to manage vegetation in a gravesite.

    Duration:
    18 minutes, 47 seconds
  • Removing Invasive Plants

    Removing Invasive Plants

    This video is part of a series of presentations and media for people interested in learning about preservation techniques to stabilize the nation's historic grave sites. In this presentation, the Chief of Historic Landscapes Program, Debbie Smith, will discuss how to review and document a grave site's flora with particular emphasis on invasive species.

    Duration:
    15 minutes, 2 seconds
  • Herbicides

    Herbicides

    This video is part of a series of presentations and media for people interested in learning about preservation techniques to stabilize the nation's historic gravesites. In this presentation, the Center's Chief of Materials Conservation, Mary Striegel, will discuss recent research investigating the effects of herbicides on historic materials and appropriate products to use in your historic site.

    Duration:
    5 minutes, 32 seconds
  • Overview of Herbicides

    Overview of Herbicides

    Sigfredo E. Faría discusses a variety of herbicides and their proper uses.

    Duration:
    3 minutes, 24 seconds

Turf

Grass is the primary ground cover on most historic cemeteries and should generally be maintained as lawn for cemeteries built after 1831. A relatively high frequency of mowing is often better to prevent grass from growing too thick, making it more difficult to remove and thus creating a potential for harm to grave markers. It is also best not to mow grass too short as that creates conditions amenable to weed infestation.

Overdressing turf in the fall with compost is a natural solution for maintaining health. If fertilizer is needed, use only natural organic fertilizers to prevent long term damage to grave markers, particularly those made of marble and sandstone. Natural organic fertilizers have a much lower salt index than synthetic organic or synthetic inorganic fertilizers. After application be sure to remove fertilizer residue from grave markers with a low-pressure hose or spray bottles. Maintaining a proper soil pH is important not only for plant growth but also to help protect grave markers. A pH of 6 to 7 is recommended for turf in Massachusetts and can usually be achieved by adding limestone to acidic soils.

To control weeds, diseases, and insects, utilize alternatives to chemicals and establish a monitoring system for early detection in accordance with Integrated Pest Management (IPM) practices. Exercise caution when using herbicides and pesticides as many of them also have a high salt content that can damage stone markers and create unsightly “dead zones” in a historic landscape.

Mulching practices can be adapted to decrease the maintenance burden of leaf removal as well as promote composting. At Mount Auburn Cemetery mowers are equipped with mulching blades with exhaust chutes padded with fire hose to prevent marring stones. Mulching mowers collect leaf debris that has been cleared from sensitive stonework and drainage areas with blowers. Special blades on the mower cut and mulch in one pass, leaving mulch to decompose over winter, enriching soil with nitrogen.

Erosion and Compaction

Erosion is unsightly and presents a direct threat to the cemetery because it rapidly hastens degradation of monument foundations, paths, walls, and landforms. Controlling erosion by maintaining vegetative cover and properly managing overland storm water flow is essential. In areas without storm drainage systems, like our earliest burial grounds, it is imperative to prevent concentration of overland flow to avoid potential erosion. This entails providing smooth gradients that will spread the surface water evenly over the landscape.

Compaction, or the consolidation of earth, retards vegetative growth by reducing the soil’s water holding capacity and air spaces. This, in turn, leads to erosion. Compaction is typically caused by overuse, either vehicular or pedestrian. To relieve these effects, managers should try to redirect vehicular and pedestrian movement so as to minimize compaction. Then, periodic aeration in the late summer or early fall with a core aerator may often be desirable. Aeration should be limited to a depth of 6 inches to protect against potential damage to buried resources, and aeration equipment should remain at least 12 inches away from grave markers.

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Last updated: October 13, 2022