November 28, 2023
The Searles Gardening Team
Many myths about Australian native plants believed to be fact may lead gardeners to lose plants. Plants that naturally populate in the Australian bush do so only in regions that suit their needs.
Parent plants already survive there because it has the right soil type, rain levels, amount of sunlight, nutrients available in the region, and number of pests. Often, plants growing in the dry bush look sparse, and those in the rainforests look lusher. Gardeners often fail to grow Australian natives from regions outside the plants' natural requirements or expect a dry climate variety to look lush in the rainforest setting. Be mindful of their natural growing habits and select plants suitable for your climatic area.
Plants native to rainforest regions will always need plenty of water, not just while establishing. A tree such as Tristaniopsis laurina, or the water gum grows along rivers and creeks and needs a steady supply of water, so the roots grow deep to anchor it into the ground. A dry forest shrub such as Leptospermum polygalifolium will need regular watering until it is established, which may take up to 18 months. A good rule of thumb for watering is once a day for the first week, every second day for the second week and twice a week until established. Deep watering is best practice when you water so the roots grow deeper into the soil and cope better with dry, harsh weather.
In their natural growing regions, there would be leaf litter, animal droppings, decaying wood, or animals releasing nutrients into the soil. This process may not be the same in your garden, so a healthy plant needs to receive extra nutrients externally. Synthetic fertilisers release nutrients to the plant, and organic fertilisers help improve the soil and provide nutrients to the plants. Note on the bag of fertiliser how often to reapply and consider applying a soluble fertiliser (one you add to water) to give them a well-rounded balance of nutrients. Use a fertiliser specific for Australian native plants as it is low in phosphorus. A higher level of phosphorus will kill some species. Searles Native Plant Food can be applied every 8-10 weeks during main growing season (spring to autumn).
For many plants, a trim after flowering will assist the plant in its shape or form. It also removes dead or damaged branches and helps promote more flowering and a lusher look. Many Callistemons look sparse if left to their natural growing height, but trimmed callistemons in topiary forms look lovely.
Not every plant can withstand frost, snow, humidity, heavy rain, low rain, etc. It is essential to choose a plant suitable for your region. Unless you go to extreme measures to accommodate a plant's needs not suited to that region, they will not last long. Plant a Grevillea in heavy clay, and once it gets past the initial planting hole and into the clay, it will likely die from root rot in wet weather. It is fine when it is just getting hand-watered in the dry times, but once a wet season hits, they do not often survive.
Some but not all Australian native plants only grow in soils with low phosphorus. Use one specific to their needs to ensure you are not planting them into the ground or a pot with higher phosphorus levels. Searles Native Plant Specialty Mix, for both garden and pot use, is low in phosphorus but loaded with nutrients to keep them happy and healthy. This mix is perfect for all Australian native plants. Also, some native plants hate their roots teased before repotting and may die. Grevillea, Protea and Banksia are some of these.