Banksia marginata

Silver Banksia, Honeysuckle

Family: Proteaceae

A shrub to tree, growing to 12 m tall with tessellated bark. It has a much wider distribution compared to other banksias, growing to as far west as the western plains in NSW, found in all coastal, tablelands and western slope subdivisions, extending into Victoria, Tasmania and South Australia. It is found in dry sclerophyll woodland, forests and heathlands and shrublands, on sandstone or sandy soils usually as well as sandy loams.

The leaves are alternate to pseudo-whorled, heavily clustered along the stems, linear to oblong, to 60 mm long and to 10 mm wide, dark green above and with a silver surface of hairs underneath which is very eye-catching when plants are blowing in the wind. The leaf margin can be entire or strongly toothed, mostly in the upper part and somewhat recurved.

The inflorescences of banksias are generally referred to as spikes or a spike-like structure which consists of fused racemes of paired flowers (hence it gets referred to as a conflorescence). There can be 100s of flowers in each spike. The flowers of banksias have 4 tepals (petals or sepals) in a tubular formation, 4 anthers hidden inside and an elongated carpel (female part) where the style and extends outwards forming the edge of the spike (somewhat similar to individual grevillea and hakea flowers).

In this species, the spikes are generally to 10 cm long and up to 5 cm wide, with each flower thin but up to 3 cm long, bright deep yellow to pale yellow and can be produced in large number, creating a stunning chandelier-like effect, especially when plants are symmetrically rounded and short.

The spike then turns into a cone-like structure of follicles; a fruit which splits open on one side. Each follicle has one or two winged seeds which is actually a fruit in itself called a samara. The follicles can take a long time to mature and open, usually needing a fire or a drying out period. Each “cone” can produce a fair amount of seed with this species having follicles to 17 mm long.

In the garden

A popular plant in the garden and reported to be not overly fussy regarding soil type, though they mostly grow naturally on sandy soils. Advice is that it is best to grow local forms in your garden (or as close as you can find).

Plant in a sunny spot and allow for drainage but plants will tolerate some moisture. Many banksias benefit from growing on a slight slope. Do not mulch too heavily and try to keep grass away from the trunk. Very hardy once established. It is excellent for attracting honeyeater and other birds.

Slow growing but will grow consistently if happy and will form a very nice shrub after a few years.

Will likely grow to about 3 to 4 m in a garden (although this will take time) and tends to spread widely, so allow some space. Very suitable for sandy gardens.

Do not apply a high phosphorus fertiliser as Proteaceae are generally sensitive.

Prune after flowering or harvest cut flowers. Can be trained into a denser shape with periodic pruning. This species can be shaped into a dome where foliage will extend to ground level, creating a very attractive and dense plant. Reported to tolerate frost.

Susceptible to Phytophthora and any other root rotting fungus.

Propagation

Propagation from seed is very reliable and not too difficult.

Other information

A similar species is Banksia canei (Mountain Banksia), which is found in the subalpine regions of NSW and Victoria. B. canei has stronger leaf venation and more strongly pointed leaf tips.
Cultivars available include “Minimarg” and “Bright”. Both are likely just natural forms of the species from specific areas.

This species can regenerate after fire from the seed bank or from a lignotuber as well as branch buds (epicormic shoots). However, it is reported that some forms of the species do not exhibit a lignotuberous capacity.

Banksia – named in honour of Joseph Banks (1743 – 1820), famous naturalist and botanist on the Endeavour and other expeditions, and President of the Royal Society for over 40 years. The genus was named in his honour by Linnaeus filius (Carl von Lynne – the Younger, son of the famous Carl von Lynne (Linneaus)).

marginata – Latin referring to “with a distinct border” referring to the leaf margins which are prominently reflexed and toothed in some forms.

Not considered to be at risk in the wild. Very common

http://anpsa.org.au/b-mar.html
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Banksia~marginata

https://www.anbg.gov.au/gnp/interns-2012/banksia-marginata.html
https://www.gardeningwithangus.com.au/banksia-marginata-minimarg-banksia/

By Dan Clarke