The riparian zone of a property is the interface between land and a river, stream or waterway. When planting a riparian zone it is important to consider the following:
1. Purpose of planting: You will need to understand what the purpose of planting the riparian zone is for your property. It may fall into one of these categories:
- Bank Stability
- Fish Habitat
2. Distance will dictate: If the distance between the fence and stream edge is less than 3.0m the ability to achieve the above purpose is limited so anything less than 1.5m is best left in rank grass, apart from planting the odd specimen tree for aesthetics.
3. Planting only one side: Where the drain/stream requires regular cleaning, plant the “northern side” of the riparian zone with the taller trees to help shade the waterway and use low growing plants on the southern bank with just the odd tall tree. This will allow the digger to operate over or around them.
4. Flooding: In streams that flood, only plant sedges in the “flood zone” because the taller plants are prone to entrap debris, divert rushing water and compound the erosion. Avoid planting flaxes in the flood zone as they are prone to washing out and causing debris build-up downstream.
5. Erosion: Steep stream edges often suffer from erosion therefore consider battering the bank edge back and planting with sedges. Sedges help reduce water velocity when it floods and also make sure you comply with any local consents.
6. Fencing: Try not to plant so close to the fence that the plants interfere with the electric fence.
7. Spraying: Spray before planting a riparian zone, consider the existing vegetation and whether to blanket or spot-spray. For pasture grass it is recommended to spot-spray as the remaining grass will help suppress weeds between new plants. However, if the area is covered with Kikuyu grass it is better to blanket spray.
8. Spacing: Plant spacing for the flood zone in the riparian zone is roughly 1.0 x 1.0m for the sedges and for the trees and shrubs, 1.6×1.6m.