Septic drainfields can be tricky places to landscape over and around. There are a few things that you should be sure not to do over your drain field and you’ll likely have heard that you should steer away from anything except lawn over your drainfield. While this is true, there are plants that can actually be beneficial to plant on top of and near your drainfield.
Don’ts
No edible plants or vegetable gardens- The soil on top of your drain field can become contaminated with viruses or bacteria so it’s best to keep edibles away from the septic area.
No standing water (rain gardens, swimming pools, water features, underground irrigation lines, etc)- You want to avoid any situation where your drain field area could become oversaturated.
No vehicles, heavy machinery, or compaction- Compaction can create create soil and drainage issues, and the weight from the vehicles and heavy machinery can break the underground lines. You’ll also want to avoid digging with machinery or digging down too deep to avoid breaking lines. Septic lines can be as little as 6 inches below the ground.
No decks, patios, driveways, buildings, etc- You don’t want any kind of hard or impervious surface or any type of building located over your drain field as it will impede drainage and will block access to the lines if maintenance or replacement is needed.
No trees, large shrubs, or water-loving plants- Keep these plants and other deep-rooted plants at least 10 feet away from septic lines to avoid roots growing into the perforated pipes and clogging them. Any water-loving or water-searching plants should be kept at least 20 feet away (the further the better with these ones).
Do’s
Test your soil- Because the soil in and around your drain field can be high in salt or other nutrients, it’s a good idea to get your soil tested to see if you need to add any amendments before planting.
Use gloves- Similar to the reasons for not planting edible plants over your drain field, you should wear gardening gloves when handling the soil in the drain field area to avoid viruses and bacteria.
Use shallow-rooted plants- Shallow-rooted plants such as ornamental grasses, native turf grasses, flowers, and herbaceous perennials all work well over drain fields or around septic lids. Shallow-rooted plants can also help prevent erosion especially if you have an elevated mound system or a slope field. Plant roots also help with the purification process and help remove extra nutrients and moisture from the soil.
Use native, drought-tolerant plants- Once established, these plants typically don’t require extra irrigation as they have adapted to the regions’ weather cycles.
Plant Options
Turf Grass: If you have a large area to cover, this is the easiest and cheapest option. The lawn will help hold the soil in place and manage excess water. Grass roots won’t grow deep enough to clog pipes or tanks.
Ornamental Grasses:
Pennisetums such as Hameln, Little Bunny, or Karley Rose– These vary in height and the foliage and flower plumes will hold on through the first couple of frosts providing textural interest in the winter. Spring and summer brings green foliage followed by fluffy flower plumes in summer and foliage turns a golden yellow color in fall. They can be cut back in later winter/early spring before new foliage emerges.
Carex such as Eversheen, Everest, or Evergold- Most sedges (Carex) will work over drain fields as they can handle both sun and shade and are semi-evergreen to evergreen so they provide year-round interest. While we normally love Carex obnupta (Slough Sedge), avoid using this specific one on your drain field as it is a water lover and we don’t want anything that will search for water.
Calamagrostis x acutiflora ‘Karl Foerster’- If you’re wanting to add some height this grass is a great option as it won’t get too out of hand. The foliage mound grows to about 2 feet tall but the flower stalks will reach up to 6 feet tall. Flower stalks appear in late spring/early summer and will continue through fall. Can be cut to the ground in late winter/early spring before the new foliage appears.
Perennials for Sun
Wildflowers such as Echinacea, Yarrow, Rudbeckia, Coreopsis, and Aster- These plants are great to add a pop of color especially around septic lids to help take your eye away from the lids. You can find them in all shades of colors and varying heights to fit any space.
Sedums such as Autumn Joy, Black Beauty, Angelina, and Bertram Anderson- Sedums like Autumn Joy and Black Beauty add a shrub-like feel without introducing fibrous or woody root systems. Angelina and Bertram Anderson are great groundcover options. You’ll find sedums in shades of green, purple, lime-yellow, and burgundy foliage making them great options for adding foliage color and texture.
Campanulas such as Birch Hybrid, White Clips, and Dickson’s Gold- A great low-growing option for septic areas. The green, semi-evergreen foliage is topped with a carpet of bell-shaped flowers in shades of white or purple-blue that will last through the entire summer.
Lavenders such as Hidcote or Alba- While Lavenders are a show stopper in the summer with the purple or white flower spikes, it’s also great as the foliage hangs on into the winter. This can be a good option to substitute for small woody shrubs that won’t work in a drain field. While lavender is edible, just remember not to ingest any plants in or near your drain field.
Arctostaphylos uva-ursi (Kinnikinnick)- This evergreen groundcover has light pink bell-shaped flowers that are followed by ornamental berries. Foliage turns shades of red and gold in fall. Great option to help with erosion especially if you have a mounded system.
Perennials for Shade
Astilbes- One of our favorites for hiding septic lids can also be used over your drain field. The fern-like foliage comes in shades of purple, green, and gold, and the feathery flower stalks in warm colors from pure white to brilliant red in summer.
Brunnera macrophylla ‘Jack Frost’- The silvery green, large leaves will brighten any shaded space and are topped with little blue flowers in spring.
Hellebores- A shady evergreen, these are some of the first flowers to emerge in late winter or early spring. The leathery foliage can be found in green, gray, or silvery shades and flowers can be single or double depending on the look you’re going for. There are a ton of flower color options as well making this a versatile perennials to place in your drainfield or near septic lids.
Asarum caudatum (Western Wild Ginger)- The heart-shaped leaves are evergreen on this slow-spreading groundcover and produces a ginger-like scent when the leaves or roots are crushed. In late winter/early spring, deep maroon star-like flowers appear.
Beesia deltophylla- Similar in shape to Asarum, the glossy evergreen foliage slowly spreads to form a groundcover that’s great for complimenting taller plants. Star-shaped flowers rise above the foliage in spring.
Septic areas can feel daunting to tackle so if you’re not sure where to start, feel free to contact us! What plants have you found that do well in your septic drain field or near your septic lids? Let us know in the comments, we’d love to hear from you!
~Colleen
Great article!! Thank you.
Thank you!