Various Banksia species have been introduced into South Africa for the cut-flower industry. However some of these species show invasive tendencies. Ten Banksia species have been identified by the Invasive Species Pogramme as invasives and we are looking to find and remove populations that are problematic. We respect the flower growing trade and the benefits the flow from them and we do not intend to remove populations that are currently being managed by flower farms, but we do want to keep a record of all naturalising populations. Please contact us if you see any of these species spreading by themselves: Banksia ericifolia, Banksia serrate, Banksia intergrifolia, Dryandra formosa, Banksia speciosa, Banksia coccinea, Banksia hookeriana, Banksia prionotes, Banksia spinulosa and Telopea speciossima. Contact: Ernita van Wyk (firstname.lastname@example.org) or Nolwethu Jubase (email@example.com).
Banksia is a large genus of trees and shrubs consisting of 172 species in the Protea family that are widespread in Australia (D. Moodley et al). Over the last few decades at least fourteen Banksia species have been introduced to the fynbos areas of South Africa, mainly for the cut-flower industry (floriculture) (S. Geerts et al). Because of the commercial importance of these Banksia species and in general the increasing interest in this family in horticulture, introduction pathways are increasing. Banksia species were predicted to be high risk introductions in South Africa; specifically B. ericifolia was classified as a potentially invasive species in fynbos (Geerts et al. 2013). Five Banksias species are known to be naturalising in South Africa in various localities in the Western Cape Province but are not legally declared according to the Conservation of Agricultural Resources Act (CARA) or the National Environmental Management: Biodiversity Act (NEM:BA). There has been a suggestion that naturalising members of the Banksia genus in South Africa should all be classified as NEMBA 1a, based on research on B. ericifolia showing that fire can drive long lag phases and that this may lead to a false assumption that these species may pose low risk (Geerts et al). The majority of Banksia species produce showy inflorescences with copious amounts of nectar to attract birds. Banksia species in South Africa usually set two seeds per capsule, except for Dryandra formosa previously known as Banksia Formosa which sets one seed per capsule (D. Moodley et al). Winged seeds are stored in woody follicles which open after fire (serotiny) with some species releasing seeds upon maturity. There is no seed bank in serotinous species. The character most commonly associated with Banksia is the flower spike, an elongated inflorescence consisting of a woody axis covered in tightly-packed pairs of flowers attached at right angles.
The following is a description of ten Banksia species that SANBI’s Invasive species programme has identified as species that are able to naturalise and invade Fynbos. Please assist us by notifying us of populations of these species that are spreading where they shouldn’t.
The South African National Biodiversity Institute’s (SANBI) Invasive Species Programme, funded by the Department of Environmental affairs, aims to reduce the threat of biological invasions through detection, identification assessment and management of invasive species that may be contained or eradicated.
Common name: heath-leaved Banksia, needle-leaf Banksia
Banksia ericifolia is a proposed 1a NEMBA and is native in Australia, Invasive in United Kingdom and Hawaiian islands. Banksia ericifolia is a large shrub of 3-6 m tall. Leaves are small, narrow linear dark, 9-20 mm long and 1 mm wide, two small teeth at the tips, crowded leaves, alternately arranged on the branches. It has a smooth grey-coloured bark with thin lenticels, thickened with age. Flowers are long orange or yellow candle-like flowers appear from April to September in South Africa, spikes 7-22 cm tall and 5 cm wide; hooked styles projecting from the axis of the flower spike. Old flower spikes fade to brown and grey with age. Seeds are retained in woody follicle, cones.
Common name: Saw Banksia; Old man Banksia
Banksia serrata is a tree that can grow up to 15 metres tall in favourable conditions. Sometimes it is much lower, forming a gnarled and stunted small tree with blackened rough bark as a result of surviving many bushfires. It has a creeping habbit. Although the species does not develop a lignotuber, the thick rough bark allows it to regenerate by sending out epicormic shoots from beneath the bark a week or so after the fire has passed. Plants of B. serrata therefore are able to resprout after fire. If fires occur before newly established plants are fire-tolerant, populations will decline.
Common name: Coast banksia
B.integrifolia is an attractive shrub or tree that can grow up to 20 metres tall with upright, cylindrical heads of pale yellow flowers. It is a popular garden plant and easily recognized by their characteristic flower spikes and fruiting “cones” and heads. Leaves are evergreen, linear to oblanceolate or obovate, greyish-green above, silvery beneath, entire or with a few teeth towards the tip, 5-15 cm long and 2-7 cm wide. The leaves are borne alternately on the stem. Flowers are usually pale yellow to yellow, but may be greenish or pinkish in bud. The fruit is cone-like, with scattered fertile capsules, which open with two rounded, woody lips. The winged seeds are flattish and black. Unlike most other species in the genus, B. integrifolia does not require bushfires to trigger the release of the seeds from the fruit.
Common name: Showy dryandra
This species used to be called Banksia formosa but it is now Dryandra Formosa. D. Formosa is a medium to large shrub which may reach 3 metres x 2 metres (sometimes larger). The leaves are linear, 50-180 mm long by about 10mm wide and regularly toothed to the mid rib with triangular lobes. The flower clusters may be up to 100 mm in diameter and occur at the ends of the branches in spring. They are usually yellow to orange in colour and are popular as cut flowers.
Common name: Showy banksia
Banksia speciosa is a dense, rounded medium-sized tree or large shrub which grows to 8m tall in height and whose flowers are often commercially used in cut-flower arrangements. B. speciosa leaves are green above and white underneath. The linear leaves may reach 45 cm long, and are divided into small, triangular lobes. The leaves are thin with prominent triangular “teeth” along each margin, which are 20–45 cm long and 2–4 cm wide.The prominent cream-yellow flower spikes known as inflorescences appear throughout the year. As they age they develop up to 20 follicles each that store seeds until opened by fire. The fruit is yellow-green and grows 2 to 2.5 inches across, and looks like an apple.
Common name: Scarlet Banksia
Banksia coccinea has only been recorded in three sites in South Africa and has not been recorded to naturalize. This species is generally a shrub to about 4 metres but can grow taller. The leaves are broad with toothed margins. The conspicuous flowers are fairly squat in comparison with other Banksias and bright orange/red in colour. The spikes are about 100mm wide by a similar length and are held terminally on the stems. They are seen in late winter through to early summer (June to January). The seeds are enclosed in follicles attached to a woody cone and are generally retained within the cone until burnt. B. coccinea is fire-sensitive in that it does not have lignotuber for vegetative regeneration after bushfires. The species relies on seed for regeneration.
Common name: Hooker’s Banksia, Acorn Banksia
Banksia hookeriana is an outstanding ornamental rounded shrub 6-8m tall with acorn-shaped orange flower heads. Grown commercially for cut flowers. Tolerant of light frost and extended dry periods. Prefers well-drained soils in full or partial sun. Ornamental landscape shrub often producing over 100 flower-heads per season. The flowers are orange in colour.
Common name: Acorn banksia
Banksia prionotes is often a tall shrub or small tree to about 10 metres. The leaves are linear, about 150-300 mm long by 20 mm wide and have deeply serrated margins. The cylindrical flower spikes are conspicuous as they occur at the end of the branches (terminal). They have a distinct “acorn shape” as the flowers open and are orange in colour about 100-150 mm long by 80 mm diameter. Flowering is usually during autumn and winter. The seeds are enclosed in follicles attached to a woody cone and are generally retained within the cone until burnt. This species is fire-sensitive in that it does not have a lignotuber. It therefore cannot regenerate vegetatively after being burnt in a bushfire and relies on seed for regeneration.
Common name: Hair Banksia
Banksia spinulosa varies greatly in height (1 -3 m) and flower colour, with variations of brown, red, orange and gold. The flower spikes range from 10-20 cm in length. The individual flowers open from the top of the spike and provide a long flowering period from autumn through the winter to spring when the three stages of cone development can be observed – bud, flower spike and seed capsule. Leaves are long and narrow, 3-8 cm long by 2-7 mm wide, and variably toothed. Multistemmed shrub to 3 m high, lignotuber present; bark smooth to tessellated, grey-brown; branchlets tomentose to hirsute. Leaves alternate, scattered, narrow-linear to oblong or narrow-elliptic, 3–10 cm long, 1–10 mm wide, apex obtuse to truncate, base cuneate, margins flat to recurved or revolute, mucronate, usually toothed in upper part, lower surface concealed or conspicuous; petiole 1–3 mm long.
Common name: New South Wales Waratah
Telopea speciosissima is an upright shrub to about 3 metres but is often shorter. It usually grows as a single or few-stemmed plant until it is cut back by fire. The plant then regenerates from an underground lignotuber and may become multi-stemmed. The leaves are large, leathery and may be irregularly serrated. They are up to 250 mm long. The flowers occur in a tight cluster at the ends of the erect stems and, overall, the inflorescence can be 150 mm or more in diameter and is usually a brilliant red. Large, leafy bracts occur at the base of the inflorescence.
Australian Native Plants Society, http://asgap.org.au/d-for.html
Geerts S, Moodley D, Gaertner M, Le Roux JJ, McGeoch MA, Muofhe C, Richardson DM and Wilson JRU (2013). The absence of fire can cause a lag phase—the invasion dynamics of Banksia ericifolia (Proteaceae). Austral Ecology 38:931-941.
Moodley, D., Geerts, S., Richardson, D.M. and Wilson, J.R.U. (2013). Different traits determine introduction, naturalization and invasion success in woody plants: Proteaceae as a test case. PLoS ONE, 8, e75078
New South Wales Flora online, http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Banksia~spinulosa