There has been a renewed interest of late in Australian native plants as drought conditions continue and gardeners and garden designers alike look for indigenous trees, shrubs and flowering plants that have the best chance of thriving in the local growing conditions. Here are just a few general tips for choosing and growing native plants.
Choosing plants
Before you buy any plants, take a tour of established native gardens in your area and visit the local botanic gardens in you have one. If you do this during a hot, dry summer you will get a good idea of which plants are most drought-resistant.
Ask are your local garden centre or a specialist native plant nursery for recommendations of plants that are indigenous to your area or for native plants that match your local growing conditions.
Know your soil
Familiarise yourself with your soil. If you are lucky you will have a well-balanced loam, neither sandy nor stiff with clay, as this is as desirable for native plants as it is for exotics. If you don’t, you can improve your soil by digging in organic matter or you can make an effort to identify plants that can tolerate sand and clay.
The most important thing is that the soil be well-drained. Some native trees and shrubs don’t mind damp soil but most need good drainage — and poorly drained soil is a breeding ground for root fungus (die-back), perhaps the most serious problem with native plants.
Bushland gardens
If you are making a garden on former bushland and want to save some of the trees, try not to change the level of the soil around them. Heap extra soil around the roots and the plants may suffocate. Lower the soil level and you may expose formerly buried roots, or worse, cut a significant number and you run a real risk of losing your tree.
Some native trees are particularly sensitive to being disturbed, including some eucalypts and rainforest trees.
Sourcing plants
The biggest range of native plants will be found at a specialist native plant nursery. You don’t necessarily have to visit them as you can buy online or over the phone and the plants will be sent out to you. Garden centres are now stocking a greater selection of native plants and the same rules apply as when buying exotics. Read the plant label to check if the growing conditions and mature height of the plant is correct for your garden, and check that the plant is upright, the leaves are healthy and the plant is not pot-bound.
Pot bound is bad
Native plants should not be pot-bound. If you discover that the roots are wrapping around the rootball inside the container instead of mainly heading downwards then remedy this at once. You can either tease them out or take a sharp knife and make a couple of vertical slashes (not too deep) to the circling roots; the new roots will grow out from where you cut.
Generally, native roots are not good at breaking out of circles and a plant placed in the ground in a pot-bound state may starve because its roots never make it out into the open ground.
Pests and diseases
If the plant is flourishing in a soil and climate congenial to it, it should be able to defend itself against most pests and diseases. However, there are things to watch out for. Scale insects, for example, are bothersome to a wide range of plants but can be crippling to some tea-trees and young eucalypts, especially those not growing in their place of origin. A spray of white oil will kill off the scale.
Other things to keep an eye out for include norers, which tend to target acacias and ink disease (a fungus) can affect kangaroo paws, especially when they are grown in humid climates. If you suspect an insect infestation or the onset of a disease, consult a reliable reference book or a specialist native plant nursery.