Grevillea – Life expectancy

There are over 340 different species of Grevillea with a quite variable life expectancy within this group. Some shrub species may only live for 5 to 10 years in their natural conditions, while others, such as the G. robusta (a rainforest tree from northern New South Wales and southern Queensland which is known as the ‘Silky Oak’), live for well over 150 years. Broadly speaking, most species have a life span range of 15 - 30 years.

With the ongoing drought conditions, many plants in the home garden are under considerable stress and many shrubs with shallow root systems, even our Australian natives, are particularly vulnerable and Grevilleas are no exception. It is important to mulch around the plants and keep them watered in summer. Grevilleas are also susceptible to some pests including insects and soil borne diseases.

Grey water

Some of the plants suitable for filtering grey water include:

Submerged and emergent species

• Baumea rubiginosa
• Baumea tetragona
• Crassula helmsii
• Eleocharis sphacelata
• Isolepis fluitans
• Ottelia ovalifolia
• Potamogeton tricarinatus
• Myriophyllum crispatum
• Myriophyllum simulans
• Triglochin procera
• Triglochin striata
• Ranunculus amphitrichus
• Isolepis inundata
• Persicaria decipiens
• Eleocharis acuta

Emergent species

• Alisma plantago-aquatica
• Baloskion tetraphyllum
• Villarsia exaltata
• Villarsia reniformis

Please note:

• Although not as good for filtering as submerged species, emergent species will help stabilise sloping edges if developing a landscaped wetland.
• If the system is connected to storm water pipes from a roof, then the size of the wetland/pond that is to be used will be determined by the volume of water passing through it.
• The speed of water flowing through the pond must be sufficiently slow to allow satisfactory filtering.
• It may be necessary to occasionally drain the wetland and defoliate the plant material to remove any accumulated heavy metals and toxins.
• Thorough research should be undertaken before installing a grey water system.