Banksia blechnifolia | Growing + Care Guide Australia

What is Banksia blechnifolia?

Banksia blechnifolia, or Southern Blechnum Banksia, forms part of the Proteaceae family and features some really fantastic foliage. This species offers stunning serrated, reddish foliage which resembles a fern as well as stunningly long flowerheads. 

While there are over 75 different species of Banksia which grow naturally across most western parts of Australia, Banksia blechnifolia is one of the few which has no underground root stock and grows wide rather than tall. 

As such, it has also been afforded the name ground cover banksia. On average, Banksia blechnifolia will only grow as much as 0.5 metres tall, but one plant can reach as much as 4 metres wide. 

The ground cover banksia Australian native is best known for its fantastic blooms, which flower in spring and range from red, pink, orange and brown. 

Why Grow Banksia Ground Covers

When it comes to the landscaping applications, banksia ground cover varieties like Banksia blechnifolia are fantastic as they take up a lot of space, offer eye-catching flowers and require fairly little care. 

This species of Banksia is great for erosion control and can be used as a ground cover, feature plant or even a border plant amongst your flowerbeds. 

Another great benefit is that the banksia ground cover produces nectar-rich blooms, which will attract a range of bees, butterflied and nectar feeding birds to your backyard. 

How to Grow Banksia blechnifolia

Banksia blechnifolia is particularly hardy and once established grows well when left alone. While it is possible to grow in a container, it’s a fiercely spreading plant so growing in your garden will be your best option. 

Of course, when propagating, you’ll need to start in a pot before transplanting into soil. 

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Propagation of southern Blechnum Banksia is most viable through seeds, as seeds are readily available, and germination only takes a few weeks. You can also propagate using a stem-cutting, but this method is far more difficult.

Propagating Banksia blechnifolia

How to Propagate Banksia blechnifolia from Seed

Growing Banksia blechnifolia from seed is by far the easiest and cheapest method. Seeds are usually readily available from existing plants. Plus, they remain viable for an extremely long time. Here’s what you’ll need to do. 

• Remove seed cone from an existing B. blechnifolia plant. 
• Place the seed cone into the oven at 120°C for an hour. 
• Using a pair of sterilized tweezers, gently extract individual seeds. 
• Fill a pot with 3:1 perlite to peat potting soil mix and wet thoroughly.
• Place the seed on top of the soil and cover with a fine layer of soil. 
• Mist regularly so as to keep soil moist, without dislodging the seed. 

Germination will take place within 3 to 6 weeks. Try to keep your seedling in a semi-humid, bright area while germinating. 

How to Propagate from Cutting

This method is not as widely used as it just not as successful as propagating from a seed. It’s also important to note that it is illegal to remove cutting from banksia plants in the wild, due to the devastating dieback issue Australia is facing. 

However, if you have a Banksia blechnifolia growing in your garden and like a challenge, you can: 

• Remove a stem cutting with a few, strong leaves. 
• Ensure you sterilize your cutting fully with a Dettol and sodium mixture. 
• Once sterilized and dried, dip the cut end into a rooting hormone. 
• Plant into potting mix. 

It’s recommended to try a few cuttings at once, as not all of them will root. 

Where to Grow Banksia blechnifolia

Ground cover banksia grows in a variety of environments and is particularly frost-hardy. In general, it’s recommended to plant your Banksia blechnifolia in a courtyard, at the poolside, in coastal gardens or in rocky terrains. 

You’ll just need to ensure the right amount of sun and average quality soil. 

• Sun - As with most banksia species, this variety loves a lot of sun. Try choosing a spot which gets almost a full day of sun. 
• Soil - Banksia blechnifolia love gritty soil, so sandy or loamy soil is perfect for ideal growth. In general, they prefer saltier soil to try to maintain a soil pH level between 5.5 and 7.0.

How to Care for Banksia blechnifolia

Once established, there’s not much you’ll need to do to keep your Banksia blechnifolia happy. You’ll only need to regulate occasional watering, annual fertilisation and periodic pruning. 

How to Water Banksia blechnifolia

Once your ground cover banksia is established, it won’t need much watering. If it’s the rainy season, you can cut back completely. If it’s a dry season, water only once a week. 

This species is particularly drought-tolerant, so don’t worry too much if you forget to water it. 

Fertilising Banksia blechnifolia

It’s recommended to use a slow-release fertiliser at the time of planting. Try a fertiliser which will last at least 8 to 9 months. Thereafter, consider fertilising every other spring. 

Be sure to avoid any fertiliser with phosphorous, as it can pose deadly for banksia plants. 

Pruning

As with most Banksia varieties, pruning should mainly be done to maintain plant size. Removing old plant cones will also promote frequent flowering.

How long does Banksia blechnifolia take to flower? 

It’s blooms are one of the most attractive features of the Southern Blechnum Banksia, however it will take some time for them to begin flowering. 

This variety will take 4 to 5 years post planting to begin flowering.

Common Banksia blechnifolia Problems

While pests are not a common problem, Banksia blechnifolia is prone to scale and dieback. To manage scale, cut back any infected leaves. Use a rubbing-alcohol or neem-oil to help prevent the spread and rub regularly on twigs. 

The Dieback Issue

Cinnamon fungus, or Dieback, is becoming a major problem for the ecology in Australia. Dieback not only affects the plants but also spreads into the soil. 

Phytoclean is one of the only registered, effective treatments for cinnamon fungus, however, it won’t be effective on curing your plants. 

Should you suspect your plant of having a dieback issue, remove the plant immediately and burn it to avoid spreading the disease to other plants. Then clean your hands, clothing and shoes thoroughly with Phytoclean to further contain the spread. 

Banksia blechnifolia Frequently Asked Questions

How long does it take for banksia to grow from seed?

With most species of banksia, germination should occur within 2 to 8 weeks depending on the conditions. Higher temperatures may inhibit germination. 

Does Banksia blechnifolia have invasive roots?

Banksia roots are not commonly known to be invasive. The roots are actually quite shallow so they shouldn’t damage any foundations or piping. 

What is the lifespan of a banksia?

Most banksias can live for over 100 years. 

How fast do banksia trees grow?

Banksias take about 5 to 6 years to reach their full height and maturity. 

Should I cut off dead banksia flowers?

As banksias flower on old wood, you should avoid pruning them behind the old blooms. For the best results, just snap off spent flowers and you should still get a healthy amount of flowers next year. 

Why is my banksia not flowering?

There are a couple of possible reasons. Firstly, there could be too much shade which will make flowering very difficult for most banksias. Alternatively, if your banksia is growing in heavy soil or clay, it will struggle to grow and flower. Try another spot in your garden with more sun and better soil. 

Do banksias grow well in pots?

If your garden soil conditions are not optimal, you can grow your banksia in containers. Be sure to use containers with good drainage and plant in quality, well-draining soil.