Growing Banksias in tropical North Queensland
This article is extracted from Yuruga Newsletter
Vol 11 No 3 (August 2003)
The focus of this article is for gardeners in tropical Australia.
However, the basic principles apply for throughout Australia
with minor modifications for local conditions.
Banksias, named after Joseph Banks who collected the first specimens in 1770, are amongst the best known Australian wild-flowers.
With their absolutely magnificent flowers and characteristically Australian appearance, everyone wants to plant these wonderful plants in their gardens, and books and magazines are full of enticing photos of amazing banksias to grow.
But … there’s a trap of course! Most of the fantastic banksias featured in glossy books and magazines and on television programmes are from south west Western Australia and are quite unsuitable for planting in gardens in tropical north Queensland. This is because the climate of south west WA is almost the exact opposite of north Queensland. South west WA experiences cold wet winters and hot dry summers while here in the monsoon tropics of north Queensland we have warm dry winters and hot wet summers. Unfortunately, banksias from south west WA simply cannot handle a tropical wet season, and they quickly succumb and die.
So, the solution is quite obvious ….. simply plant Queensland banksias! And luckily, there’s several really nice ones to choose from, as you can see from those illustrated here. With the exception of the Hinchinbrook Banksia (Banksia plagiocarpa) which has quite specific cultivation requirements, all the banksias described here are remarkably easy to grow and are suitable for gardens right across tropical north Queensland.
Banksia flowers are renowned for their copious production of nectar, and so banksias are wonderful plants to attract honeyeaters to your gardens. Banksia flowers are stunning in a vase or in floral art, and the gnarled seed pods that form after the flowers have finished make terrific dried arrangements and ornaments.
There’s a few tricks you need to know in order to grow banksias successfully:
- Firstly, as a general rule they do not like wet feet and so they should be planted in friable, well drained soil. The exception to this rule is the Swamp Banksia (Banksia robur) which is more than happy in sodden ground – the more water the better as long as the soil does not turn sour.
- Secondly, to get lots of flowers they should be planted in an open position that gets full sun for most of the day.
- Thirdly (and very, very importantly!) be very careful what fertiliser you use. Banksias are extremely sensitive to phosphorous. It is very easy to poison them by inadvertently applying a fertiliser with too much phosphorous, and this is true of most general garden fertilisers. The golden rule is to make sure that the fertiliser you use has a phosphorous content of 3% or less. Look for a fertiliser that is specifically labelled as suitable for natives, and check the phosphorous level on the label before you use it! For more information, pick up the Yuruga Information Sheet “Fertilising Native Plants” next time you visit Yuruga Nursery.
Hill Banksia (Banksia spinulosa)
Banksia spinulosa is one of the showiest of the banksias, bearing a multitude of large bright orange brushes for a long period each year. This plant is a dense hardy shrub growing to about two to three metres in height, and is a prolific flowerer. A plant in full flower makes a superb floral display, and attracts a host of honeyeaters.
Best planted in a full sun position, this shrub makes an excellent screen plant and retains its compact habit with minimal pruning.
Hinchinbrook Banksia (Banksia plagiocarpa)
Banksia plagiocarpa is a stunning and unusual banksia. Quite rare in the wild (it is found only on Hinchinbrook Island and the adjacent coastal mainland) it is a small tree growing to about 3- 4 metres high. This banksia has fantastic velvety bronze new growth, attractive toothed leaves, and the most fantastic flowers which start out as blue-grey buds, opening to yellow.
This banksia is much sought-after in the cut flower industry. However, it is the most difficult to grow of the Queensland banksias, preferring the cooler, moister conditions found in the Atherton and Malanda areas of the Tablelands.
Coast Banksia (Banksia integrifolia)
Banksia integrifolia is a small, gnarled tree with an interesting form. This species is quite tolerant of windy coastal conditions and salt spray, and it makes an excellent feature, especially in coastal gardens where it thrives on sandy soils.
It has grey-green leaves which are silvery-white beneath, and bears yellow banksia flowers for a long period during the year.
Mountain Banksia (Banksia aquilonia)
Banksia aquilonia is an attractive small tree in the garden, with lovely decorative foliage and yellow banksia brushes. This banksia occurs naturally in the rainforest margins on the mountains throughout north Queensland. Easy to grow, it is happy in dappled shade and also makes a very attractive pot specimen especially if it is kept heavily pruned to encourage the formation of dense foliage.
Giant Candles (Banksia ‘Giant Candles’)
Banksia Giant Candles is a hybrid between the Heath Banksia (Banksia ericifolia) and Banksia spinulosa, and it displays the best features of both its parents. A large shrub growing to 3 – 4 metres high, it has fine soft foliage and a dense compact form which lends it to use as an excellent screen plant.
The flowers are spectacular, giant, candle-like, bright orange brushes up to 30 cm long, and they are borne in profusion. Preferring a well-drained, sunny, open position, this superb banksia attracts myriads of nectar-feeding birds when in flower.
Cape York Banksia (Banksia dentata)
Banksia dentata is a handsome small tree from the open forests and heathlands of Cape York Peninsula. It has attractive, toothed leaves (hence the name ‘dentata’) which are green above and white beneath, and produces masses of yellow bottlebrush flowers each year, mostly during the dry season.
This banksia has an unusual corky trunk, and often grows into a twisted, gnarled shape which adds a distinctly Australian character to the garden.
Swamp Banksia (Banksia robur)
Banksia robur is a very handsome shrub with enormous, serrated, dark green leaves. It has most unusual flowers which start out as an olive-green colour as buds, open out to beautiful golden brushes, and mature to rich brown spikes before forming decorative pods.
Growing to only about 2 metres tall in most situations, this banksia prefers lots of water and will tolerate swampy conditions.