Banksia robur
swamp banksia
Open shrub. Branches hold very wide, lush leaves with serrated edges. Large tan to purple-red-brown flowers. Tolerates more water and heavier soil than most banksia.
 Height | 4–10ft |
|---|---|
 Width | 4–6ft |
 Tolerates | Drought, Moist Soil, Pots |
 Water needs | Moderate |
Banksia are from mediterranean climates of Australia and adapt well to California, particularly along the coast. Once established they will grow and look their best with deep watering every other week to once a month during summer. We have a friend who grows this plant in heavy clay in an area that has ground water (to the point that it weeps during the winter) in SSZ 16. The plant seems content to grow happily without additional water during winter, and only a deep once a month hand watering during summer. | |
 Hardy to | 26°F |
 Exposure | Part Sun – Full Sun |
 Plant traits | Flowering, Foliage Feature, Shrub |
 Indoor / outdoor | Outdoor |
 Drainage | In Ground: Cactus Mix, In Pots: Cactus Mix, Tolerates Heavy Soil, Tolerates Sandy Soil |
 Fertilizing | Bloodmeal, Fish Emulsion, Low Needs, No Phosphorus |
 Origin | E Australia |
 California native | No |
 Sunset zones | 14–24 |
Growing Notes
Chlorosus can be common with this plant (irregular yellowing of leaves due to a PH imbalance). Correct this by adding cottonseed meal or cheated iron.
Special Interest
This plant displays cauliflory, where flowers can emerge on the trunk instead of among the branches, often at the base. Just one more reason this lovely banksia!
The above information reflects the observations of Grubb and Nadler and our extended plant community. We always consider input from fellow horticulturists and welcome feedback from those with additional information on the culture of this plant.
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