Scientific name: Banksia marginata
Plant type: Evergreen tree or shrub
Environment: Full sun to part shade, prefers well-drained soil
Bloom: Tight cylinders of yellow flowers, old flower heads will persist on plant
Uses: Screen planting or specimen tree
Australia – 1J, 60B
Silver banksia (Banksia marginata) is a large shrub or tree native to Australia. There it is found in the states of New South Wales, Victoria, and Tasmania, off the southeastern coast. Within this range it has large populations and is not considered to be threatened.
The English common name silver banksia comes from the appearance of the leaves. The small leaves have a dark green upper surface, and the lower side is covered with fine, white hairs that can appear silvery. The flowers are arranged in large conical inflorescences. There are hundreds of small, yellow flowers in these inflorescences which will open starting at the bottom of the cone.
Silver banksia is known to be variable in terms of its habit. The plant will typically range from a medium sized shrub to a tree over 40 ft tall. More extreme examples have been reported, however, including a shrub of less than 8 inches tall and individual trees up to 100 ft tall in Tasmania.
Banksia marginata, like most other banksia species, produces large amounts of nectar making it popular with pollinators. In its native range it is visited by birds, insects, and even some small mammals. The seeds are also eaten by native cockatoos in the region including the yellow-tailed black cockatoo (Zanda funerea).
Silver banksias occur in fire prone regions and have adapted to this. After a fire individuals of Banksia marginata will regenerate through one of two methods. Some release copious amounts of seeds that germinate after fire. Others have a swollen structure above the roots called a lignotuber where it will resprout after a fire. In addition to be being fire adapted, silver banksia is known to be one of the most cold hardy banksias, withstanding temperatures down to 14° F.
Banksia marginata was used by indigenous peoples, such as the Koorie from southeastern Australia, for various uses. Dried inflorescences were used as water strainers and fresh inflorescences were soaked in water to make a sweet drink. Banksia marginata is also popular in cultivation and was first grown in Europe at Kew Gardens in England in the early 1800s. A dwarf selection of silver banksia is even used in bonsai.
IN BLOOM CONTRIBUTORS: Text, Photos, and Profile by Victoria Stewart.