Native plants and water-use: some common misconceptions

At SKINC we feel that it is an over-simplification to say that all native plants (or all indigenous plants) are drought-proof, low-water use, and never need to be watered. The following are our responses to statements that we frequently hear.

"Native plants don't need water"

Plants naturally grow in an association with other species that like the same conditions - this is called a vegetation community. The major communities present in the Port Phillip area are Coastal, Wetland, Grassy Woodland and Heathland.*

If plants come from a Coastal community they are used to growing in dry sandy soils and are very likely to thrive with minimal or no watering. If plants come from a Wetland environment (which includes plants that are fully submerged year round as well as plants that are only seasonally inundated) they will not be happy in a dry situation with no watering. Using such plants doesn't mean that you have to water regularly - a better way of gardening is to place these plants where there is permanent or even irregular standing water. Plants from a Grassy Woodland or Heathland community lie somewhere between these two extremes, with each plant species having different water needs.

Before choosing a plant always check its water requirements.

*for more detail on local vegetation communities see Indigenous Plants of the Sandbelt (p. 13)

"Australian plants have survived for thousands of years without irrigation so they're the best for your garden"

It's true that Australian plants have evolved many strategies to survive in poor soils and tough climate. However these strategies don't always ensure luxuriant looking plants in tough seasons. Some of these strategies include drawing nutrients down into the root systems during summer eg. lilies die down over summer and re-sprout in autumn, and grasses brown off over summer and become green again with autumn rains.

Having a garden that looks good throughout summer may mean mixing local plants that are not at their peak at this time, with local plants that do maintain their good looks all summer, and with exotic drought-tolerant plants such as those from Mediterranean or desert environments.

"So if this is a drought tolerant plant I don't need to water it, do I?"

After plants leave SKINC they will either be planted in the ground or kept as pot plants.

All plants need water to establish in the garden. Plants must get a good watering in when first planted. Whilst getting established (usually a plant's first year in the ground) it will also need some additional water. How much it needs will depend on the season in which it is planted and how long it takes to get its roots established. After this first year you may never need to water your native plants again - depending on that plant's tolerances.

Pot plants always need to be watered. A plant in the ground can extend its roots to make use of any soil water available. A plant kept in a pot can only access the water in an extremely limited area. Pots also dry out faster than open ground. There will be variation in the length of time you can go between watering depending on the species i.e how long can a plant tolerate drying out. Observe your plants and work out the optimum length of time you can hold off watering. On very hot or windy days all plants in pots will suffer unless watered. Putting a saucer under each pot will reduce watering as plants will be able to draw up water from here.