Swamp Banksia

Swamp Banksia (Banksia robur) is the banksia for the wet corner of the garden, the one spot where most shrubs rot. It settles at around 2.5m tall and 2.5m wide as a spreading shrub, with broad leathery leaves the size of your hand and upright spikes that open lime green and age to bronze gold. Honeyeaters work those spikes for weeks, and the spent cones hold their shape long after flowering.

Why you'll love it

• It genuinely handles wet feet. Most banksias demand sharp drainage. This one grows in coastal swamps, so a damp low spot suits it rather than kills it.
• Flowers that last. The spikes shift from green through yellow to bronze over several weeks, then persist as sculptural cones.
• Bold foliage all year. Serrated leaves up to 30cm long give a coarse, architectural texture against fine leaved natives.
• Birds and pollinators. Nectar heavy flowers pull in honeyeaters, native bees and butterflies.
• Poor soil is no obstacle. Sandy, low fertility ground is its natural home, so it asks for very little.

Where it works best

Mass planting. Plant 1.5m apart. At that spacing the plants merge into a continuous low thicket within about three seasons.

Damp and low lying ground. Swales, the base of a slope, a dam edge or a bed that stays soggy after rain. This is where it beats every other banksia.

Coastal gardens and borders. Salt tolerant and comfortable in humidity, so it holds up on exposed sandy blocks. Repeat it along a border at 1.5m for rhythm.

Growing Swamp Banksia in Australia

Position and climate. Full sun brings the heaviest flowering, though it accepts part shade with a looser habit. This is a plant for tropical, subtropical and warm temperate gardens. It takes light frost only, so cold tablelands and hard frosting southern gardens sit outside its range.

Soil. Sandy and slightly acidic is ideal, and poor ground is fine. Unlike its relatives it does not need mounding for drainage. Keep phosphorus away from it: use a native specific fertiliser, never a general garden blend.

Water and feed. Deep water twice a week through the first summer, then it looks after itself. A light dose of low phosphorus native fertiliser after flowering is all it wants. Mulch 75mm deep, clear of the stem.

Pruning. Tip prune after flowering to hold it compact. It reshoots from a woody lignotuber, so an old leggy plant can be cut back hard and will regrow from the base.

What to expect when it arrives

It is grown in four sizes: tube, 140mm in packs of ten, 200mm in packs of six, and a single 300mm pot. Tube and 140mm plants are the sensible choice for a mass planting, arriving young and single stemmed but quick to establish. The 200mm and 300mm sizes give a bushier plant and bring first flowering closer.

Plants travel upright and are delivered Australia wide, with delivery from $29.95 and a minimum order of $300 before delivery. Advanced and large stock is freighted at cost. Expect little visible movement for the first month, then steady growth, with first flower spikes usually in the second or third year. Every plant is covered by our 30 day healthy plant guarantee.

Plant care guides and related reading

• Compare the full banksia range
• Native plants that bring birds into the garden
• Plants for coastal and salt exposed gardens
• Shrubs suited to mass planting

Common questions

How big does Swamp Banksia actually get?

About 2.5m tall and 2.5m wide in a garden, growing as a spreading shrub rather than a tree. Older listings quoting 10m are describing a different species entirely.

Will it survive in soil that stays wet?

Yes, and that is its advantage over other banksias. It grows naturally in coastal swamp country and copes with ground that holds water for days after rain, though it will not sit in a permanent pond.

What fertiliser should I use?

A low phosphorus native fertiliser, applied lightly after flowering. Standard garden fertilisers carry enough phosphorus to damage banksia roots, so check the label before you feed.