Ask Mr. Smarty Plants

You really have to consider the whole system when planting over it, because of the damage roots can cause. The tank should be sealed to prevent roots invading it, but you don't want to take any chances, and certainly the lateral lines are not protected.  

You don't want any woody plants close to your lateral lines, as in trees and shrubs. They are the ones that send roots out far beyond their driplines, sneaking up on you. But you also should not leave that area completely bare, because you know it wouldn't stay bare, it would get weedy and unless it was mowed, some of those "weeds" would grow up to be woody plants.

After doing some research on landscaping over septic systems, the piece of information we were most interested in was that perennial short grasses should be planted above the lines. Apparently, the shorter the grass, the shallower the roots. Furthermore, the grasses will assist in evaporation from those lines, and should thrive with that unaccustomed dose of moisture. We could find no specific information on Clay County, Indiana nor any advisories concerning septic systems there. So, we're going to assume that the use of native grasses over the entire system is the safest, most economical way to maintain that system. We will check with the USDA Plant Profile on each plant to assure that it is native to your area in west central Indiana.

We're going to go to our Native Plant Database, go down to COMBINATION SEARCH, select on Indiana, and then "Grasses/Grasslike Plants" under Habit. From this list, we'll select some shorter grasses suitable for your purposes. These plants are all commercially available, and if you have difficulty locating sources for plugs, sod or seeds, go to our Native Plant Suppliers section, type in your town and state in the "Enter Search Location" box and you will get a list of native plant nurseries, seed suppliers and landscape and environmental consultants in your general area.  We would also suggest you contact the Purdue University Cooperative Extension Office for Clay County, which may have material available that will help you with your project.

Since you didn't specify if you have sun or shade, soil moisture, etc., you may want to go back to the Native Plant Database and put in your own requirements. Follow each link to the webpage on that grass for information on height, propagation, etc. Since this is part of your yard, we tried to choose grasses that would be attractive on their own, and do well in a nice meadow planting.

Grasses for septic system in Poland, Indiana

Bouteloua curtipendula (sideoats grama)

Carex blanda (eastern woodland sedge)

Calamagrostis canadensis (bluejoint)

Chasmanthium latifolium (Inland sea oats)

Elymus canadensis (Canada wildrye)

Elymus villosus (hairy wildrye)

Hordeum jubatum (foxtail barley)

Schizachyrium scoparium (little bluestem)

Pictures from our Image Gallery:

Bouteloua curtipendula

Carex blanda

Calamagrostis canadensis

Chasmanthium latifolium

Elymus canadensis

Elymus villosus

Hordeum jubatum

Schizachyrium scoparium