What we are talking about is situations where septic tank contents are drained through dripline into the soil. It is a great idea to have the area, planted up to help absorb waste and supress odours. And at the same time boosting the plants into a beautiful [mini] carbon sink!
We often get enquiries from the owner of a lifestyle block or rural property who have got their new septic tank system all installed and just need to plant the disposal field. They are filled with enthusiasm for getting the pretty stuff done until they need to decide what to plant. The problem they have is they know nothing about what varieties they should plant in there. And we get that… What we do know is that the following plant varieties have been proven time and again to thrive in Septic tank fields:
- Apodasmia similis (oioi)
- Austroderia richardii (Toe Toe)
- Carex (secta or virgata)
- Coprosma propinqua
- Coprosma lobster
- Cordyline Austrailis (Cabbage Tree)
- Dacrycarpus dacrydioides (Kahikatea)
- Juncus edgariae (Wiwi)
- Phormium tenax (Flax)
- Plagianthus Regius (Swamp Ribbonwood)
Why are these plants the best for your disposal field?
Disposal fields are generally have wet soils due to the constant source of grey water being distributed into the soil, so it’s important that the plants can handle ‘wet feet’. It is also important that the plants do not have long aggressive roots, as they can cause problems to the dripline once established. The list above contains only native trees, which is great for biodiversity and attracting native birds. It also offers a range of heights which can look really good when planted together and looks good all year as all these natives are evergreen!
Things to Consider:
- Making it look nice: Our preference for making it look good, is to use not too many varieties. Work with the different heights and colours to make it interesting!
- Animal friendly? If animal/stock may go near your effluent field, you may want to ensure that you that the plants you purchase are not toxic to animals, or you could consider fencing off the area.
- Do you have a height limit that you don’t want the plants to grow over? If the disposal area is under power lines or if the trees get too high, will it create shade in the wrong place?
Planting Spacing: You should allow for 1 plant per m2 for instance a disposal field that was 30m x 3m would need 90 plants.
In summary plants for a septic field need to be suited to wet soil and have shallow root that will not cause problems to the dripline. We hope this article has helped you to decide what plants to get for your septic run-off field. As always we're here to help so give us a bell if you need any further help!