|Banksia menziesii subsp. var.||Firewood Banksia, port wine banksia, strawberry banksia|
Banksia menziesii, commonly known as firewood banksia, is a species of flowering plant in the genus Banksia. It is a gnarled tree up to 10 m (35 ft) tall, or a lower spreading 1–3 m (4–10 ft) shrub in the more northern parts of its range. The serrated leaves are dull green with new growth a paler grey green. The prominent autumn and winter inflorescences are often two-coloured red or pink and yellow, and their colour has given rise to more unusual common names such as port wine banksia and strawberry banksia. Yellow blooms are rarely seen.
Generally grows on sandy soils, in scrubland or low woodland. Banksia menziesii provides food for a wide array of invertebrate and vertebrate animals; birds and in particular honeyeaters are prominent visitors. A relatively hardy plant, Banksia menziesii is commonly seen in gardens, nature strips and parks in Australian urban areas with Mediterranean climates, but its sensitivity to dieback from the soil-borne water mould Phytophthora cinnamomi makes it short-lived in places with humid summers, such as Sydney. Banksia menziesii is widely used in the cut flower industry both in Australia and overseas.
Banksia menziesii grows either as a gnarled tree to 10 m (35 ft), or a lower spreading 1–3 metre (4–10 ft) shrub, generally encountered at its northern limits in the vicinity of Eneabba-Mount Adams; thus, it declines steadily in size as the climate becomes warmer and dryer further north. In the shrub form, several stems arise from the woody base known as the lignotuber. The trunk is greyish, sometimes with shades of brown or pink, and the 2–3 cm (1 in) thick rough bark breaks away easily. The new growth is covered in fine brownish hair, which wears away after two or three years, leaving smooth stems and leaves. Stems which will bear flower spikes the following year are generally thicker and longer. Oblong in shape and somewhat truncate at the tips, the leaves are grey-green in colour, 8–25 cm (3–10 in) long and up to 4 cm (1.6 in) wide. The new leaves are paler and finely downy. The leaf margins are serrated with many small 1–2 mm long triangular teeth. The lower surface of the leaf has a midrib covered in fine pale brown hair.
Flowering occurs in autumn and winter, peaking from May to July. Overall the inflorescences, or flower spikes, take around eight months to development from the first microscopic changes in late spring. Ovoid to cylindrical in shape, the flower spikes can be up to 7–8 cm (2.6–3.4 in) wide and 4–12 cm (1.6–4.8 in) high. They are composed of numerous individual flowers; one field study south of Perth recorded an average of 1043 per flower spike, while another on plants in cultivation in South Australia recorded an average of 720. B. menziesii has more flower colour variants than any other Banksia species, with flower spikes occurring in a wide range of pinks, as well as chocolate, bronze, yellow and white, and greenish variants. They are particularly striking closeup but can look indistinct from a distance. They are most attractive in late bud, the styles contrasting well to the body of the inflorescence, the whole looking like a red- or pink-and white vertical candy striped bloom. The inflorescences are generally a deeper red after colder weather and further into the winter. Anthocyanin pigments are responsible for the red and pink shades in the flowers.
Old flowers usually fall off the spikes quickly, with up to 25 large beaked follicles developing. A mottled dark brown and grey in colour, these can be prominent and quite attractively patterned when newly developed. Oval shaped, they are 2.5–3.5 cm (1–1.4 in) long by 1–1.5 cm (0.4–0.6 in) high and 1–1.5 cm (0.4–0.6 in) wide. Overall, only a small fraction of flowers develop into follicles; the proportion is as low as one in a thousand. The plant is dependent on fire to reproduce as the follicles only open after being burnt, each one producing one or two viable wedge-shaped (cuneate) seeds, on either side of a woody separator. The colour and level of pigmentation in the seeds foreshadows the eventual colour of the inflorescences. Kevin Collins of the Banksia Farm recalled that for many years pale seeds were discarded by seed collectors who thought they were infertile. Later, he learnt that pale seeds yielded yellow-coloured blooms, dark grey the usual red-coloured, and black a distinctive bronze-coloured bloom.
Seedlings have obovate cotyledons 1–1.4 cm (0.4–0.6 in) long by 1–1.5 cm (0.4–0.6 in) wide, and the leaves which develop immediately afterward are crowded and very hairy. They have serrate margins. Evidence of thickening to form a future lignotuber, as well as minute buds, has been detected from the bases of seedlings at five months of age.
The plant is fairly easy to grow in a mediterranean climate with good drainage and a light (sandy) soil It generally does poorly in eastern Australia, although it is grown commercially in southeastern South Australia as a cut flower crop. It is also grown in California and Hawaii.
The plant favours sandy well-drained soils and a sunny position and can be heavily pruned if necessary, as new growth can arise from the lignotuber.
Seeds do not require any treatment prior to planting, and take 26 to 40 days to germinate. Seeds that grow into yellow-flowered plants are pale and unpigmented, while future bronze- and red-flowered plants are dark greyish and black respectively. It generally takes about five to seven years to flower from seed. Although it is readily propagated by seed, experiments with in vitro propagation found Banksia menziesii to be more difficult than other species trialled.
Pests and diseases
With medium to high susceptibility to Phytophthora cinnamomi dieback, it is unreliable in conditions which favour the growth of the soil-borne water mould, such as summer humidity or poor drainage. The use of phosphite fungicides does reduce the spread of Phytophthora.
- ↑ Cowling, Richard M.; Lamont, Byron B. (1985). "Variation in serotiny of three Banksia species along a climatic gradient". Australian Journal of Ecology 10 (3): 345–50. doi:10.1111/j.1442-9993.1985.tb00895.x.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Template:The genus Banksia L.f. (Proteaceae)
- ↑ Fuss, A. M.; Pattison, S. J.; Aspinall, D.; Sedgley, M. (1992). "Shoot growth in relation to cut flower production of Banksia coccinea R.Br. and B. menziesii R.Br. (Proteaceae)". Scientia Horticulturae 49 (3–4): 323–34. doi:10.1016/0304-4238(92)90168-C.
- ↑ Fuss, A. M.; Sedgley, M. (1990). "Floral initiation and development in relation to the time of flowering in Banksia coccinea R.Br. and B. menziesii R.Br. (Proteaceae)". Australian Journal of Botany 38 (5): 487–500. doi:10.1071/BT9900487.
- ↑ Whelan, Robert J.; Burbidge, Allan H. (1980). "Flowering phenology, seed set and bird pollination of five Western Australian Banksia species". Austral Ecology 5 (1): 1–7. doi:10.1111/j.1442-9993.1980.tb01225.x.
- ↑ Clifford, S. C.; Sedgley, M. (1993). "Pistil structure of Banksia menziesii R.Br. (Proteaceae) in relation to fertility". Australian Journal of Botany 41 (4–5): 481–90. doi:10.1071/BT9930481.
- ↑ 7.0 7.1 7.2 7.3 Collins, et al. pp. 266–67.
- ↑ Asenstorfer, Robert E.; Morgan, Anne L.; Hayasaka, Yoji; Sedgely, Margaret; Jones, Graham P. (2003). "Purification of anthocyanins from species of Banksia and Acacia using high-voltage paper electrophoresis". Phytochemical Analysis 14 (3): 150–54. doi:10.1002/pca.696. PMID 12793461.
- ↑ Young, Andrew Graham; Clarke, Geoffrey Maurice (2000). Genetics, demography and viability of fragmented populations. Cambridge University Press. p. 256. ISBN 0-521-79421-8.
- ↑ 10.0 10.1 Collins, Kevin (2004). "Seed variation in Banksia menziesii". Banksia Study Group Newsletter (ASGAP) 6 (1): 1. ISSN 1444-285X.
- ↑ Mibus, Raelene; Sedgley, Margaret (2000). "Early lignotuber formation in Banksia – Investigations into the anatomy of the cotyledonary node of two Banksia (Proteaceae) species". Annals of Botany 86 (3): 575–587. doi:10.1006/anbo.2000.1219.
- ↑ Sweedman, Luke; et al. (2006). Australian seeds: a guide to their collection, identification and biology. CSIRO Publishing. p. 203. ISBN 0-643-09298-6.
- ↑ Tynan, K. M.; Scott, E. S.; Sedgley, M. (2000). "Banksia propagation. In-vitro multiplication of Banksia species". Australian Plants 21 (166): 79–82.
- ↑ McCredie, T. A.; Dixon, K. W.; Sivasithamparam, K. (1985). "Variability in the resistance of Banksia L.f. species to Phytophthora cinnamomi Rands". Australian Journal of Botany 33 (6): 629–37. doi:10.1071/BT9850629.
- ↑ Shearer, B. L.; Crane, C. E.; Fairman, R. G. (2004). "Phosphite reduces disease extension of a Phytophthora cinnamomi front in Banksia woodland, even after fire". Australasian Plant Pathology 33 (2): 249–254. doi:10.1071/AP04002.