Mitcham pond and rain garden

Graham in Whitehorse

Our wetland garden is based on a small pond and cascade that was professionally constructed about 6 years ago. 

The area has a thick rubberised membrane overlaid with rocks, pebbles and mulch.  The water is sourced by diverting one of the downpipes draining part of our nearby house roof.  There is a buried pit with waterproof lining with a pump that recycles the water back up to the top of the cascade.  This creates a gentle flow through the system.  Any overflow from the system discharges to a series of earthen sumps lower down the garden.  This only occcurs after exceptionally high rainfall.

The wetland is planted with local Australian plants – mostly indigenous species. 

It’s constantly evolving with some species thriving, others struggling.

Best species have been:
 
  • Carex fascicularis
  • Nymphoides montana 
  • Mazus pumilio
  • Ranunculus glabrifolius
  • Lythrum salicaria
 
All of these now naturally reproduce in the wetland.  Some regular control is needed to stop Carex and Ranunculus from taking over.
Geranium solanderi and Patersonia occidentalis both do well in the margins as well as the Carex and Mazus. 
 
The water supply seems quite nutrient rich (lots of possum poo on the house roof is probably the main culprit) .
 
Southern Brown Tree Frogs and Striped Marsh Frogs seem to come and go, but I haven’t seen evidence of breeding.  Insect life in summer is pretty interesting with Dragonflies and Damselflies common.  Blue Banded bees love the Lythrum when it’s in flower.
 
The water flow seems to avoid mosquito larvae becoming an issue but no doubt inhibits other aquatic species.
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