Use caution when planting around septic systems
By Tim Daly
Gwinnett County Extension Agent
Throughout Gwinnett County, many homes have septic systems. Homeowners frequently contact the Extension office inquiring what they can plant on and around it to avoid causing harm to the system.
Many plants are beneficial in these areas in that they manage the amounts of soil moisture and absorb nutrients. However, the use of the wrong type of plants can damage the septic system and lead to costly repairs. By following some simple guidelines, plants can be installed in these areas that will not disrupt the septic system.
Certain plants by their nature have a greater potential to disturb the septic drain field systems. Shallow rooted annual and perennial herbaceous plants can be planted closer to the drain fields since they do not have invasive roots. Turfgrass can be grown over the drain field and is beneficial since it helps hold the soil in place. Trees and shrubs should be planted away from it since they have extensive root systems. A good rule of thumb is to use the ultimate mature height of the selected tree as the minimum planting distance from the septic drain field. Avoid plants with aggressive, water loving deep roots that typically thrive in wet locations and can clog or disrupt the pipes in the system. Some plants, such as willows and river birches, are known for invading septic lines. Others to avoid include magnolias, poplars, red maples, sugar maples, and elms. The extra moisture and nutrients are favorable to the growth of the roots of these plants causing the lines to become clogged. You can plant shallow root trees and shrubs, such as crabapples, dogwoods, hemlocks, hollies and arborvitae towards the drier ends of the drain lines.
Avoid the placement of groundcovers, such as English ivy or liriope, over septic drain fields. They can form thick mats and collect leaf debris preventing the soil from being able to dry out.
Locate vegetable gardens away from the septic drain fields. The vegetables, especially root vegetables, could become contaminated with disease-causing microbes. Different soil types vary with their ability to filter contaminants; however, there is no way to be certain that everything is filtered out. Additionally, frequent tilling and working of the soil could damage the lines.
Avoid the application of excessive amounts of mulch or soil on top of the drain field. Raised beds should not be installed over it. These actions can cause the soil to become compacted and by preventing soil moisture from evaporating can lead to detrimental impacts on the performance of the system.
Use care when choosing plants to install around your septic drain field. The use of proper ones will reduce the likelihood of damage to the system and provide an attractive landscape.
Timothy Daly, is an Agricultural and Natural Resource Extension Agent with Gwinnett County. He can be contacted at 678-377-4010 or firstname.lastname@example.org