What are Banksia trees?
The Banksia tree is a very distinctive plant with an iconic appearance due to its cone-shaped fruits that remain firmly closed for many years. The Banksia is named after the botanist Sir Joseph Banks and remains one of the most popular trees found in Australian gardens.
Are Banksia trees native to Australia?
So, are Banksia trees native to Australia? Yes, and no! You see, there are 173 different Banksia and all of them except for one occurs in naturally in Australia. This one exception is the Dentata (a tropical Banksia), that can be found on islands to the north of Australia, including New Guinea and the Aru islands.
The greater diversity of Banksia can be found in the South-West of Australia (with 60 different Banksia species being recorded) and they remain a very important part of Australia’s flora on the East coast as well.
There are also a few Banksias that are found in both the arid areas of Australia and its rainforests.
The beloved Banksia tree is a protected species by the Australian Government.
How big do Banksia trees grow?
So, how big do the esteemed Banksia trees actually grow? Banksias can range anywhere from a low-growing shrub, all the way up to a whopping 25-metres tall (and beyond).
These plants tend to grow best in well-drained soils with plenty of sunlight.
Most Banksia trees respond rather well to a light pruning – however, the Lighnotuber species can be heavily pruned.
For feeding, only fertilisers that are low in phosphorous should be used.
The species that are native to Western Australia are unfortunately prone to a root-rot fungus and thus typically does not grow well in high-humidity regions in Australia.
Are banksias slow or fast growing trees?
Banksia are actually a slow-growing tree, however, they are very long-lived and can take several years to properly flower. They have beautiful foliage and develop a unique, gnarled and ‘warty’ grey trunk as they age.
Are banksias toxic?
As for the toxicity of Banksias, the trees are not regarded as toxic at all.
How to care for a Banksia tree
The Banksia tree is so popular in Australian gardens because it boasts nectar-filled flowers that attract all manner of bees and birds. They also make wonderful cut indoor flowers when they release their delightful ‘honey’ scent.
If you want to grow and care for a Banksia tree of your own, here’s everything you need to know…
First, you must choose a sunny situation for your Banksia to be planted. You need free-draining soil in order to prevent the tree from developing root rot. These trees are happy in sandy soils, though they do appreciate a little organic matter from time to time.
As for clay soils, they need to be enriched with gypsum with a raised bed to assist with drainage other the Banksia will not thrive.
The main taproot of the Banksia tree can take up to two years to be fully established. Make sure that you keep a close eye on them during the first two summers of their lives, and ensure that they have plenty of extra water when necessary during especially hot periods. Following that, Banksia tends to be rather drought-resistant.
Particularly if you are growing a Banksia from a seed, you’ll be pleased to learn that they germinate easily and can take as little as a few days to establish.
Fertilising your Banksia
Banksia have very special roots (aka proteoid roots) that can help them to grow comfortably in Australia’s low-nutrient soil. As such, they don’t tend to require much in the way of fertilisation at all. That, and as mentioned above, they are particularly sensitive to phosphorous.
However, if you do want to apply some organic fertiliser for good measure, we recommend doing so twice a year while double checking the labels to ensure that they are indeed safe for natives and have less than 2% phosphorous.
What are the most common pests, diseases, and problems for Banksia trees?
While the Banksia trees are relatively resilient and have great survivability, like all trees, they are not entirely impervious to pests and diseases. Here are some of the more common issues faced by Banksia trees:
- Caterpillars are notorious for attacking Banksia. Keep a close eye on yours – particularly for signs of leaves and foliage being eaten.
- Scale are pesky sap suckers that, if left untreated, can cause sooty mould to develop – which can be especially dangerous for Banksia trees.
- Root rot occurs when there is poor drainage and this disease can be very dangerous for a Banksia tree. If you notice the leaves turning brown, while clinging to the braches, your Banksia could be in serious trouble. The best way to prevent this is by improving soil drainage and adding organic materials like compost in order to rebalance the helpful microbes in the soil.
- Phosphorous toxicity, as mentioned earlier, is a very real risk for Banksia trees so you must monitor the amount of phosphorous that your tree encounters. If your Banksia has yellowing leaves with brown tips and edges, it could be a result of this ailment. You can alleviate this by adding OCP eco-seaweed to your soil, thus building up the strength and vitality of your Banksia on a weekly basis. Adding iron is also a very effective means of reducing excess phosphorous levels.
Pruning a Banksia
Again, most species of Banksia enjoy a light pruning once a year. If you do plan to prune your Banksia, make sure that you are very careful as this is a protected species, native to Australia. When in doubt, hire professional tree pruning by Lakeside Trees and Stumps to be on the safe side!
