Waranga News

Banksias brighten up a winter garden

2020-06-18

Banksias brighten up a winter garden image

The onset of winter brings the striking flowers of the many Banksia species to the fore.

These striking and attractive Australian native plants have tough, often serrated leaves and large, erect cones of stiff flowers in shades of greenish-white, yellow and orange through to pink and red. Banksias range from ground covers, low growing shrubs to small trees and are great plants to attract bees and nectar feeding birds into the garden. Banksias also make great cut flowers indoors where they’ll release their honey scent.

Banksias also produce very distinctive woody seed pods which you’ll instantly recognise as the big bad Banksia men if you’ve read the children’s book “Snugglepot & Cuddlepie” by May Gibbs.

There are more than 170 species of banksias with all but one being endemic to Australia .Probably the most common species grown in the home garden are Banksia spinulosa, Banksia speciosa and Banksia ericifolia while the cultivars ‘Giant Candles’ and ‘Birthday Candles’ are also popular with their prolific flowering.

How to grow Banksias

Choose a sunny position where the soil is free draining to avoid them developing root rot. They are quite happy in sandy soils but will appreciate a little organic matter being added. Clay soils will definitely need improving with gypsum and you should also raise the garden bed to assist with drainage. Apply liquid seaweed in the first few weeks to help settle the banksia into its new home.

Banksias lack a main taproot and can take two years to fully establish themselves. Keep an eye on them for their first two summers and provide extra water during hot periods if needed. After that they’ll be quite drought resistant.

If you want to grow banksias from seed the good news is the seeds are very viable and will easily germinate in a few days. Extracting the seed from the cone however is the tricky part! They are deep inside the cone and the capsules only open after exposure to high temperatures eg bushfires. To mimic this place the cone in an oven for 1-2 hours at 100-150 degrees celcius and the capsules will open releasing the seed. Watch that the cone doesn’t catch alight.

Sow the seed either directly into a garden bed or in very free draining native potting mix. Water in with liquid seaweed and before you know it, you will have baby banksias!

Fertilising Banksias

Banksias have special roots called proteoid roots which help them to grow in our low nutrient Australian soils. As such they require little fertilising and are particularly sensitive to high levels of phosphorous, especially when they are young. Once or twice a year, apply a certified organic fertiliser which is labelled safe for natives or has a phosphorus content less than 2%.

If you have young plants that you want to push along then apply liquid seaweed every 2-4 weeks as this are safe for all natives.

Pruning Banksias

Generally banksias require little pruning. Simply trim off any dead branches which may appear and prune back to restrict the size/shape if needed. Finished flower spikes left to age on the plant become quite striking in their own right.