Previously we have discussed the importance of finishing the job, which means the site is cleaned up and the backfill is done properly and leveled. In many cases, this is where the homeowner takes over and finishes the landscaping.

This is a major reason we suggest a follow-up visit about a month after installation. During that visit, you can make sure that everything is working properly and that the landscaping is completed — in a manner that will not harm system performance.

In the past, we have suggested that installers might be able to expand business opportunities by taking on the landscaping. Even if this is not where you want to go with your business, it is important that you be able to provide the homeowner with some basic information on the do’s and don’ts of landscaping.

Basic principles

These recommendations reflect our Minnesota location in that they are suited to more humid and cooler climates. However, the underlying principles apply anywhere. The right vegetative cover helps keep the soil in place, lets the system function at its best by removing moisture and nutrients from the soil, provides an insulating layer, and makes the area more attractive.

However, planting the wrong vegetation can interfere with system performance. Trees, shrubs and any herbaceous plants that have extensive root systems should not be placed on or near the system. Herbaceous plants such as turf grasses, wildflowers and native grasses are suitable for cover.

Check with your local univer-sity Extension office for a list of plants that fit this category. Alternatively, you can visit with local landscapers and nurseries for such a list.

Turf grasses have fibrous roots that hold soil in place, require maintenance similar to a lawn and are available in many varieties, including shade-tolerant, to suit site conditions.

Wildflowers and native grasses are an attractive alternative to turf grass and provide the same benefits with less maintenance and more drought tolerance. It is important to plan the site carefully to avoid problems with plant establishment caused by soil compaction.

Working with mounds

Minnesota and other Midwestern states have many mound systems. While mounds are not always desirable from a homeowner’s perspective, they do not have to look like a “big pile of dirt.”

The right landscaping can minimize the visual impact and maximize protection of the system. You can change the mound’s shape to incorporate landscaping ideas. It can serve as a privacy barrier, a windbreak, or as a screen to block unsightly views. Here are some guidelines to follow:

• Topsoil or cover should be at least 6 inches and no more than 30 inches deep.

• Use minimal tiling when planting.

• Use plants that prefer dry soils near the septic system. This will prevent their roots from interfering with the system. The larger the plant, the more extensive (though not necessarily deeper) the root system.

• Do not place trees or shrubs on the mound. For aesthetics, the mound can be framed with trees and shrubs, which should be kept at least 20 feet from the edges of the system. Trees known for seeking water such as poplar, maple, willow and elm should be planted no closer than 50 feet. Shrubs should not be planted on mounds or drainfields.

• Minimize traffic over the system. Never drive across the system, as this can cause soil compaction and lead to erosion problems. In winter there should be no activities over the top of either a mound or a drainfield.

• Do not plant edible plants on the mound or drainfield.

• Annually inspect systems for animal burrowing and tunneling. Control animals at the first signs, before they do extensive damage.

• Root barriers (geotextile fabric impregnated with a herbicide that kills plant roots) have been used on mounds. They are expensive to install, and if you select plantings properly, such a barrier should not be necessary.

Erosion control

While the plants are establishing (the first two years after planting) it is important to place a mulch or an erosion control blanket on mounds or sloping sites to reduce runoff and erosion.

Turf grasses work well for this purpose. Low-maintenance grasses such as fine fescues make a dense cover and only need to be mowed a few times a year. Fine fescues such as creeping red, hard, sheeps and chewing fescues are shade-tolerant and often are mixed with Kentucky bluegrass.

To establish grass cover, there are two primary methods: seeding and sodding. Here is a summary of the pros and cons of each:

Erosion control is important when establishing grass. An erosion-control blanket can be laid after seeds have been planted. This will help retain moisture and protect the seeds and soil. Another product available is an erosion-control blanket with seed. These blankets are made of organic material that will decompose over time.

Winter insulation

Vegetative cover is critical to insulate the system over winter. Well-established vegetation helps hold snow in place where it can insulate all parts of the system. Snow keeps the heat from the sewage and soil from escaping and keeps the frost layer shallow. In the absence of snow cover, a dense vegetative cover acts as an insulating layer, helping prevent the system components from freezing.

Following these basic land-scaping principles will result in improved system performance and prevent problems. To find out more about landscaping and homeowner maintenance, visit the University of Minnesota Onsite Sewage Treatment Program web site: http:// septic.umn.edu.

Some material in this article was taken from information provided by Jessica Wittwer of the University of Minnesota Onsite Program.