Riparian

Oioi

Oioi is a rush-like plant with jointed, cylindrical stems and grows in coastal wetlands, salt marshes, and estuaries around New Zealand.

Oioi’s dense root system helps bind and stabilize muddy and sandy soils in wetlands and estuaries.
This prevents erosion from wind, waves, and tides,protecting coastlines and riverbanks.
Acts like a natural filter, trapping sediment, nutrients, and even pollutants as water flows through the wetland.
This helps clean water before it reaches streams, rivers,or the ocean.

Harakeke has strong, fibrous roots that anchor soil and help prevent erosion during floods or heavy rainfall.
This reduces sediment entering rivers, which keeps water cleaner and protects habitats for freshwater species.
It's commonly used in riparian planting(planting along waterways) to stabilise banks and improve water quality.
It’s hardy, fast-growing, and thrives in wet soils,making it ideal for restoring damaged wetlands and streams.

This Secta is a large, tussock-forming wetland plant.
It is found around lakes, swamps, slow-moving streams,and riparian margins.It stabilizes soil and prevents erosion.
Its dense root system holds the soil together, especially on stream banks and in wetlands.
It acts like a natural sponge, trapping sediment, excess nutrients-like nitrogen and phosphorus- and pollutants before they enter freshwater.

Manuka is a small shrub or tree with tiny, pointed leaves and white/pink flowers.
Its very common across NZ, especially in poor soils and regenerating land.
Its hardy and can stabilise soil and prepare it for larger trees.
Its short but very strong roots filter sediments before they reach the waterway, improving water quality.
Irrelevant, but it produces its famous Manuka honey, known for its antibacterial properties and of course phenomenal taste.

Kanuka are very similar to Manuka but grow much larger (up to 15 meters in height) and are much more resilient to harsh conditions.
It offers shade and cooling to stream margins,which helps reduce water temperature and support the habitat of fish like tuna (eels).
They're often used in riparian plantings to restore forest cover along streams.

It is New Zealand’s tallest native tree and it can reach over 60m tall.
Their root systems absorb water, reducing surface flooding and allowing floodwaters to slowly filter into the ground.
It stops poor quality water with unwanted minerals and pollutants like fertilizer, which if to much is applied to farms it's runoff could lead to things as followed:

Rapid algae growth (algae blooms)
Reduced water clarity.
Depletion of oxygen in the water.
Due to this tree also being very tall, its canopy when fully grown shades water which is very important because most freshwater species preference cool clean water.
This is also helpful because invasive algae like Didymo (Didymosphenia Geminata) which chokes out the waterway by forming a sludgy carpet over the surface of the water don't like cool water, they thrive in warm sun exposed ponds, lakes, and streams.

Raupō (also known as Bulrush) is a dense bush looking similar to Oioi just with large brown bulbs on upper section of its tall slim leaves.
Its dense enjoined root systems can stretch over 60cm into the mud and soil trapping sediments and filtering runoff on backsides.

Totara is a hard, tough-wooded tree of about 25-30 meters tall.
Although they take time to grow, Totara trees can be stabilizing your wetland bank, with its dense root network, shading the water, acting as a buffer for nutrient and sediment runoff (especially on pasture edges), and producing berries do feed native bird life.
But it gets better! It's truly a long-term investment with it's life span of well over 1000 years if undisturbed!

So, we know a variety of plants and trees works best to avoid many things.
A few of these we now know to be erosion, sediments, pollutants, dirty water, warm water.
But if we plant we can stabilize banks, filter and trap sediments, stop those unwanted pollutants and chemicals from entering our water ways, filter and shade water with trees and plants to better support the less resilient species that live in our wetlands!