Back to roots: Embracing native proteas

By Gabrielle Stannus

From the sawtooth foliage of Banksia prionotes to the scarlet flowers of the Tasmanian waratah (Telopea truncata), the Protea family has it all when it comes to adding colour and form to a public landscape or private garden. Whilst many of us may know and use the South African species, e.g. leucadendron and leucospermum, there are plenty of Australian species in cultivation too, although there are more that I would personally like to see join this list. I spoke with David Mathews from Proteaflora about the benefits of, and tips for, using proteas in landscape and garden design.

Whilst heading up to Miena on the Central Plateau in Tasmania for a site visit recently, my partner and I stopped off along the way for a quick walk around Pine Lake, a small waterbody named for the fire sensitive tree species that surround it. The Pencil Pine (Athrotaxis cuppressoides) is a Tasmanian endemic tree or erect shrub found mostly in unburnt, high-altitude areas on or near the Central Plateau¹. I am always excited to see this pine as I use it as a case study for my geography students at the University of Tasmania, asking them to explore possible drivers of its distribution so they can better understand how to plan for and collect biodiversity data.

However, this time when visiting Pine Lake, my attention was captured by some other plants that I must admit I had barely paid more than a passing glance to in the past: Bellendena montana (Mountain Rocket), Orites acicularis (Yellow Bush), and Persoonia gunnii (Mountain Geebung). All three of these plants are members of the Proteaceae. I was entranced by the Mountain Rocket’s display of red seed pods, which follow its white flowers. To achieve this brilliant colour, winter cold is necessary². B. montana is the only species of this ancient genus and is restricted to  alpine and subalpine heaths and woodlands of Tasmania³ . According to the Plants of Tasmania Nursery, it is rarely available. Neither the Yellow Bush nor the Mountain Geebung are commonly found in cultivation in this state, although a close relative to the Yellow Bush, O. diversifolius (Variable Orites) can be picked up at specialist indigenous plant nurseries.

Proteaceae

This walk piqued my interest in the Proteaceae, and I wanted to know more about their availability and use, so I turned to protea expert David Mathews. I must admit I had an ulterior motive. I wanted to share my new-found enthusiasm for the Mountain Rocket with him too! David is the Managing Director of Proteaflora Nursery, although in a former life in New South Wales he taught high school geography. We quickly bonded over biogeography, discussing the various pathways via which proteas may have arrived in this country. Interestingly, I learnt from David that scientists have recently theorised that the iconic ‘Australian’ banksias may have originated in North Africa around 130 million years ago⁴ .

According to the Flora of Tasmania Online, the Proteaceae remains a largely Southern Hemisphere family with about 80 genera and 1700 species, with the most diversity found in Australia and South Africa⁵ . In Australia there are 46 genera (37 endemic) and around 1,100 species, of which the majority are endemic. South-west Western Australia is particularly diverse in species and genera. 16 genera are restricted to north-east Queensland’s rainforests, whilst 12 genera (3 endemic) and 30–33 species (17 endemic; possibly 3 naturalised) are found in Tasmania.

Proteaflora

David’s first foray into growing proteas was not in any of those states listed above, but rather in South Australia, where he grew banksias for cut flower production. He says, “We bought a piece of land just out of McLaren Vale at Blewett Springs on deep sand and set up the banksia plantation. And then my father got into my ear and said ‘I would really like to have an outlet in South Australia. Would you be interested in a small nursery?’” Upon his father’s retirement, David then moved to Melbourne to continue the family business, Proteaflora.

Proteaflora specialises in potted plants, often in flower, supplying retail garden centres and cut flower growers across Australia. They have partner growers overseas in the United States, Japan, South Africa, and Italy, growing under licence and using Proteaflora expertise to produce flowering pot plants. Knowing their South African proteas, especially the leucadendrons and leucospermums, I was keen to find out more about which native cultivars Proteaflora are growing.

Native proteas and their cultivars

“We made a major push into waratahs (Telopea spp.) about 30 years ago. We saw that there was virtually nothing in the nursery market, and thought, ‘This is a wonderful flower, so why not?’ Our first selection was the ‘Shady Lady® Red’, a hybrid (Telopea speciossima x oreades). We selected it because it is garden hardy and will grow anywhere where there is half reasonable soil drainage and is not too hot. We then did some further selection and breeding from that and came up with ‘Shady Lady® Crimson’, a very hardy plant which whilst not quite as hardy as the ‘Shady Lady® Red’, is most suitable for cut flower growers,” David explained. “We then teamed up with Graeme Downe who had undertaken breeding with (Telopea) oreades and (T.) monganesis. Graeme came up with a yellow flowering form, and then a very hardy white. So, we moved them into the ‘Shady Lady®’ series.”

Proteaflora has also researched and developed banksias, including Banksia spinulosa ‘Birthday Candles’, bred and selected originally by Bill Molyneux of Austraflora. This east coast banksia hails from south of Wollongong and is therefore very tolerant of coastal conditions. “This plant piqued our interest in Banksia spinulosa, and we are now in the process of looking for much wider selections of this species, given its hardiness. There is a huge variety within the species, ranging from ‘Birthday Candles’ up to small trees,” explains David.

David says Proteaflora’s interest has recently turned to a banksia from Western Australia with both red and orange flowering forms. “We have released the orange-flowering form of Banksia coccinea, and we have just located a red one from which we plan to build up numbers. B. coccinea has quite a climatic range, and it is suited to the south-eastern end of Australia. It will grow in a slightly heavier soil. We know it will flower in Monbulk (in the relatively cool Dandenong Ranges to the east of Melbourne). We believe that if it will flower here, then it should flower in other parts of southern Australia. We are also looking at grafting Western Australian varieties onto some of the eastern Australian rootstocks. However, it is early days yet in terms of our research and development, and some way off from commercial production.”

Why should you consider proteas?

“In terms of the garden and landscape, I think it is about the attractiveness, the sheer beauty of proteas, both their flowers and foliage,” says David when asked why landscapers and gardeners should consider planting Proteaceae. “I have always thought their appeal is in their flowers. However, speaking with gardeners, they tell me that they find the foliage equally appealing.

“Also, the Proteaceae, both the African and our Australian plants, fit our landscape. The birds and the bees are into them as well, they bring the wildlife into the garden. That is a major attractor for people in their gardens. They want to make their gardens part of nature and proteas can help do this.

“Interestingly, we organised some focus groups about five years ago to find out why people plant proteas. Once the conversation got going, it came out that people actually planted proteas to show off and impress their neighbours!”

Growing media

Whilst speaking with David, he generously shared with me his expert advice on caring for both native and exotic proteas.

“In terms of the soil in the garden, we are looking at an acid soil. By acid soil, I mean a pH sitting around about five and a half although the Proteaceae will tolerate a bit of a range. They want the soil to be reasonably well drained. It does not work if the soil is a brick-making clay! Somewhere between sand and clay (think sandy loam), proteas grow well. The key issue is drainage, and the soil should drain freely through the profile.

“In terms of the nutrients in the soil, proteas require a low phosphorus soil. And again, if you want me to put a number on it, less than 15 parts per million phosphorus; and that is probably what they are most fussy about. If you want to grow them using an artificial soil, then buy a potting mix formulated for natives. In those native potting mixes, they will have the NPK (nitrogen-phosphorus-potassium) ratio right.

“Considering the pH and the phosphorus, the next thing that I really push for is a high level of organics. In constructed soils, the problem usually is that the organics are low. Proteas respond well to organics which bring in biological material helping to conserve moisture, and acts to buffer nutrients that may be slightly ‘out of whack’. As the organic matter in your soil increases, the soil becomes more forgiving in terms of its phosphorus and nitrogen levels.

“Whilst some proteas grow well in a coastal environment, they do not necessarily want to get too close to the beach. I have seen proteas really struggle in beach sands where they are lacking organic matter. There are some banksias that will grow closer to the sea. I have seen Banksia praemorsa growing on more sandy soil. However, the South African Proteaceae tend to do better as you move further away from the beach, back in the sixth or seventh dune, that is, in the soils with higher organics.”

Fertilising

David acknowledged the popularity of proteas with landscapers given their relatively minimal maintenance requirements: “They really do not need a lot of water or fertiliser. So, to that extent, they are easy care.” He recommends that landscapers and horticulturists feed both native and exotic proteas with a fertiliser formulated for Australian native plants, be it controlled release, liquid, or other formulations. Most proteas possess proteoid roots, i.e. rootlet clusters which form along lateral roots. Many of these rootlet clusters are non-mycorrhizal and are highly efficient in phosphorus acquisition⁶ . In these species, proteoid roots and proteoid-like root clusters are abundant when grown on infertile soils.

“The main time that you need a fertiliser is if you are growing proteas in containers. If you put a plant in a container, it is like putting a fish in a tank. You have got to look after it, including regular watering. None of the in-soil rules apply! They want to be out in as much sunshine as possible but can always be moved to a prominent spot for a short period when in full flower. You can put any protea in a pot; however, they will eventually outgrow that container so choose the smaller growing varieties. (Banksia) ‘Birthday Candles’ is good in a pot so long as you water it, says David, adding that the ‘Little Prince’, a South African miniature King Protea also does well in containers.

“If you are growing the Proteaceae in a natural soil, most people get themselves into more trouble by over fertilising them. The default is to leave them alone unless you have got a very good reason to fertilise them. Fertilising proteas when they do not need it may result in them growing too fast and sprawly and they do not look very nice,” David adds.

Pruning

Whilst David cautions against over-fertilising, he is careful to note that this does not mean that proteas do not require your attention in the garden: “There is an old theory going around that if you have a native garden, then you do not need to do anything, that the plants will look after themselves. They do not! Pruning is critical to making these plants look good, whether they are Australian or South African proteas. If you want a general rule for all the Proteaceae, prune and shape them when they flower or just after they flower.”

David’s favourites

When prompted, David was quick to acknowledge that Banksia ‘Birthday Candles’ is his favourite member of the Protea family with pride of place in his home garden: “We have hedged them along our entry pathway, and they make a lovely border hedge. They can be pruned and shaped into anything you like. My favourite non-native is probably the ‘Little Prince’, the miniature King Protea which can be grown in pots.”

Unfortunately, I do not think that I was able to convince David of the cultivation merit of my current favourite native Protea, Bellendena montana. I will just have to speak with local indigenous plant nurseries here in Tasmania to find out if and when this plant may become available. In the meantime, there are plenty of other beautiful and unusual native and exotic proteas for me to consider in my designs, and for you to think about using too!

Postscript: The term ‘protea’ has been used here to denote a member of the Proteaceae more generally and not necessarily a species within the Protea genus unless its full scientific name is provided, i.e. written in italics, e.g. Protea cynaroides.

Gabrielle Stannus

Inwardout Studio

M: 0400 431 277

E: gabrielle@inwardoutstudio.com

References

1. University of Tasmania 2019a, Athrotaxis cupressoides, Key to Tasmanian Vascular Plants, viewed 4 March 2024, https://www.utas.edu.au/dicotkey/dicotkey/CONIFERS/sAthrotaxis_cup.htm
2. Plants of Tasmania Nursery 2019, Plant list by botanical name – B, 17 July 2019, viewed 5 March 2024, https://www.potn.com.au/plant_list_B.html
3. University of Tasmania 2019b, Bellendena montana, Key to Tasmanian Vascular Plants, viewed 4 March 2024, https://www.utas.edu.au/dicotkey/dicotkey/PROTS/gBellendena.htm
4. Lamont, B, Milne, L, Cowling, R & He, T 2024, Banksias are iconic Australian plants, but their ancestors actually came from North Africa, The Conversation, 29 January 2024, viewed 4 March 2024, https://theconversation.com/banksias-are-iconic-australian-plants-but-their-ancestors-actually-came-from-north-africa-221589
5. Gray, AM & Duretto, MF 2019, Proteaceae, version 2019:1, in MF de Salas (Ed.), Flora of Tasmania Online, 31pp. (Tasmanian Herbarium, Tasmanian Museum & Art Gallery: Hobart), viewed 4 March 2024, https://flora.tmag.tas.gov.au/vascular-families/proteaceae/
6. Dinkelaker, B, Hengeler, C & Marschner, H 1995, ‘Distribution and Function of Proteoid Roots and other Root Clusters’, Plant Biology, vol. 108, iss. 3, June 1995, https://doi.org/10.1111/j.1438-8677.1995.tb00850.x