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Grow Guide: Banksia spinulosa (Hairpin Banksia)

Banksia spinulosa is native to the east coast of Australia and can be found in all three states. There are even cold-tolerant varieties that can be grown around Canberra.

This is an easy plant to grow in a home garden and requires very little maintenance once it becomes fully established.

This banksia species will flower from autumn right through to spring and the impressive blooms are highly attractive to bees and nectar-feeding birds.

Banksia spinulosa and Townsend Warbler | Plant care
Banksia spinulosa and Townsend’s Warbler

In addition, the hairpin banksia has lovely needle-thin green leaves and an attractive rounded growth habit.

Banksia spinulosa varieties 

Banksia spinulosa is favoured by horticulturalists and commercial plant growers and many different cultivars have been propagated and produced over the years.

Here are just a few to consider:

Dwarf Banksia spinulosa varieties

  • Banksia ‘Coastal Cushions’
  • Banksia ‘Honey Pots’
  • Banksia ‘Stumpy Gold’
  • Banksia ‘Cherry Candles’
  • Banksia ‘Birthday Candles’
  • Banksia ‘Dwarf Red’
  • Banksia ‘Bush Candles’
Banksia spinulosa Birthday Candles | Plant care
Banksia spinulosa ‘Birthday Candles’ / Photo by Don McCulley / Wikimedia / CC BY-SA 4.0

Taller growing varieties

  • Banksia spinulosa var. spinulosa
  • Banksia spinulosa var. vincentia
  • Banksia spinulosa var. cunninghamii
  • Banksia spinulosa var. collina
  • Banksia spinulosa var. neoanglica
  • Banksia ‘Giant Candles’ – a hybrid between B. ericifolia and B. spinulosa 
Banksia spinulosa cherry candles | Plant care
Banksia spinulosa ‘Cherry Candles’

Choosing a location and preparing the soil

The hairpin banksia can live in most soil types including sand, loam, and clay loam. It does best in a sunny location but can handle a little afternoon shade. However, banksias grown in a more shady location will have fewer flowers.

To prepare the soil for planting your banksia, just work in a little compost or organic matter to help improve the drainage as banksias prefer drier soils. The soil’s pH level should be slightly acidic to neutral.

How to plant a Banksia spinulosa

There’s nothing difficult about planting a hairpin banksia. All you have to do is dig a hole that is large enough to accommodate the roots of the plant. In general, you want the hole to be twice the width of the rootball as this breaks up the surrounding soil and makes it easier for the roots to spread out.

hole for plant | Plant care

The planting hole should be as deep as the rootball as well. Once your hole is ready, take the plant out of the pot and gently tease out the roots a little. Place the plant into the prepared hole and backfill it with soil. Gently press the soil down to help support the plant.

Create a moat around the perimeter of the plant and fill this with water. This will stop the water from flowing away and help it to seep down to where the roots of the plant are.

Cover the soil around the plant with some well-composted mulch.

How to care for a Banksia spinulosa

Once your banksia is well-established, it will require very little maintenance. It’s a good idea to lightly tip prune your young plant in order to encourage a nice dense growth habit.

Banksia spinulosa Hairpin Banksia | Plant care

You can also prune your banksia after it has finished flowering if you wish but this is not really necessary. In fact, the withering flowers will turn into the most attractive seed heads that add to the allure of a banksia. These will eventually fall off the plant on their own.

Banksias are one Australian species that are sensitive to phosphorus. Therefore, you only want to feed your hairpin banksia with a low-phosphorus fertiliser that is specifically designed for Australian natives. You only need to feed your banksia once a year in spring.

Be aware that if you regularly apply mulch to the surface of the soil, there’s really no need to give the banksia any additional fertiliser.

Interesting fact: Banksias have proteoid roots. This allows them to survive in highly infertile soils and why these plants are sensitive to any additional phosphorus. The bottlebrush-like clusters that grow along the lateral roots are designed to process phosphorus that is already present in the soil in order to stimulate good growth.

Because banksias are drought-tolerant, they generally don’t need any supplementary watering once they’ve become fully established.

However, you should give your plant a little extra care in its first two years of growth. Check the moisture level of the soil and if it is dry, give your banksia a good soak.

Banksia spinulosa problems

Being an Australian native plant, the hairpin banksia is highly resilient and is not bothered by many pests except for the occasional caterpillar.

However, when in cultivation in our gardens, banksias may be prone to a few diseases that are mainly caused by inadequate cultural practices. Here’s what to look out for and try to avoid.

Root rot

Root rot is a fungal disease and is mainly a problem in poorly drained soils and as a result of overwatering. To avoid this problem, make sure that your banksia is growing in well-drained soil and never overwater your plant. Once your banksia is suffering from root rot, there’s very little that you can do to save it.

Phosphorus toxicity

As I’ve already mentioned, banksias are sensitive to phosphorus, so you don’t want to add any to your soil. Your banksia will display yellowing leaves with brown tips if it has been exposed to too much phosphorus.

To help neutralise the phosphorus in the soil, apply a liquid seaweed solution such as Seasol

FAQ

How tall does Banksia spinulosa grow?

A full grown Banksia spinulosa that is growing in a relatively protected environment can reach a height of 3 metre. However, those grown in more exposed conditions along the coastline will usually only reach a height of 1 metre.

How quickly do banksias grow?

Banksias are moderately fast-growing and can reach their full height within 5 to 6 years. However, the dwarf varieties tend to be much slower-growing with some only reaching a height of 0.5 metres.

Do banksias have invasive roots?

In general, banksias grown in cultivation do not have invasive roots. Banksia spinulosa, in particular, does not grow large enough to have a problem with invasive roots.

What is the lifespan of a banksia?

Certain species, like the Banksia integrifolia and Banksia spinulosa, can live for over 100 years.

Do banksias tolerate frost?

Once fully established, banksias are frost-tolerant and can even handle salt spray. This makes them ideal for coastal areas.

Can banksia grow in pots?

Yes, the hairpin banksia is perfect for growing in large pots as long as the pot has adequate drainage holes and is placed in a sunny spot in your garden. Try some of the dwarf varieties for a truly stunning display.

Photo of author

Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.

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