Grevillea robusta is the largest species in the genus Proteaceae and grows to a height between 18 to 35 metres. It can reach in excess of one metre in diameter.

Grevillea Robyn Gordon – Sometimes referred to as the Spider Flower

Grevillea Robyn Gordon – Possibly the most popular hybrid of Australian gardeners

Grevillea robusta – Known as the Silky Oak

Here are some photos I took of Protea cynaroides. This is the national plant of South Africa, native to the fynbos region. I took the photos at the UC Berkeley Botanical garden.

The name of the plant family Proteaceae and the genus Protea, derive from the name of the Greek god Proteus, who had the ability to change between many different forms. In the family and genus, respectively, there is a vast diversity of flowers and leaves. The genus Protea has more then 92 species. The species cynaroides makes reference to the artichoke-like flowerheads. The artichoke belongs to the genus Cynara. P. cynaroides has the largest flower in the genus.

A thick underground stem makes enables this species to survive wildfires.

This species can be propagated from seeds or cuttings. Cuttings should be semi-hardwood 6-10 cm long and treated with rooting hormone.

Here is a link to additional posts from this site from the Proteaceae family...

Click individual photos below to enlarge…

A variety of Protea blooms

Protea – Symbolizes diversity & courage. Signifies daring and resourcefulness and can stand for change and transformation.

The amazing variety in the size and habit of the plants, and in the size, colour and shape of the flowers of the genus Protea was the reason it was named after the Greek god Proteus, who could change his shape at will.

The Proteaceae are an ancient family, probably one of the oldest groups of flowering plants. Scientific probes into the early history of plant life have shown that the ancestors of today’s Protea were present 300 million years ago.

Protea are best represented in South Africa along the south and south western coastal mountain ranges. The other sub-family is located along the south and south western coastal areas of Australia. No genus is naturally common to both South Africa and Australia. In these areas the flowers are mostly harvested in the wild, though in later years many flower plantations have sprung up for the commercial growing of the flowers. Not all species are commercially viable for one reason or the other.

These beautiful flowers were first grown in the United States in San Diego North County, as well as some ranches in the Santa Barbara area about forty years ago. They were later grown in Hawaii. The climate and soil in these places most nearly duplicates their natural habitat. While most growers in this area are small farmers with 5 acres or less, there are also several large ranches. These beautiful flowers are shipped from here all over the United States, Japan and Europe.

There are many different types of Proteas, here’s some info on a few specific varieties:

Leucospermum cordifolium (Pincushion)

Leucospermum cordifolium

Indigenous to South Africa, it is a rounded spreading shrub up to 2m in diameter and about 1.5m high, with a single main stem and horizontally spreading stems, hard green leaves and 1- 3 large inflorescence’s borne at the end on the stem. The inflorescence’s consist of a large number of small flowers. It is the stiff protruding styles of the flowers which are the source of the common name “pincushion” for this genus. Only a few large, hard, nut-like seeds are produced by each inflorescence. In their natural environment the seeds are collected by ants, stored in the soil, and germinate only after a fire has killed the mature plants and returned the nutrients back to the soil.

Protea cynaroides (King Protea)

Protea Cynaroides

The King Protea is confusing at first glance. The enormous red “petals” seem floral enough, although larger than life but when you look into the center of the thing, you find innumerable downy structures arranged in a beautifully geometrical spiraling pattern.  The King Protea is native to South Africa. In fact, in 1976 it was declared the national plant of that country.  King Protea needs well-drained soil that’s slightly acidic (pH 5.0 to 5.5), and they need fresh air. They are bug-resistant by nature but prone to fungus problems. 

Protea neriifolia

Protea neriifolia

This protea has the distinction of being the first of it’s kind to be mentioned in botanical literature. Discovered in 1597, illustrated in 1605; yet it wasn’t until 1810 when it was officially recognized as a distinct species and therefore described and named. Protea neriifolia is a very widespread species and grows from sea level to 1300m altitude in the southern coastal mountain ranges of South Africa. The blooms of Protea neriifolia are actually flower heads that contain a collection of flowers in the center, which are surrounded by large & colourful bracts.

Lecudendron and Banksia are also popular Proteaceae family members.

Proteaceae is an ancient plant family which, according to some sources, has been around for over 30 million years. Worldwide there are more than 1500 species with most, but not all of them, occurring in the Southern Hemisphere. In Australia alone there are nearly 900 native species.

The name Proteaceae comes from the Greek sea god Proteus, who could change his shape at will. This is an appropriate name, given the wide diversity of forms encompassed by the many species that make up the family. The species most commonly found in Bay area gardens belong to the genus Protea, Leucospermum, Leucodendron, Banksia and Grevillea (see my last post for more information on Grevilleas). All are evergreen plants, and all bear colorful and unusual inflorescences, consisting of many small flowers densely packed into a head or spike.

Plants in the Proteaceae family can be small shrubs, ground covers, screen plants or even large trees. They are fast growing, and their foliage can be fine and needle-like, or large and leathery. They are generally very drought resistant and tolerate, or often prefer, poor soil. All Proteaceae are pollinated by birds and mammals.

Protea is both the botanical and English common name of the genus also known as Sugarbush, which is native to coastal South Africa. The flower heads, consisting of tight clusters of tubular flowers surrounded by brightly colored bracts, are borne at branch ends, looking something like very colorful artichokes. Protea make terrific cut flowers, holding their color and shape for weeks.

Leucospermum, also known as Pincushion, are also native to southern Africa, where they occupy a variety of habitats including scrub, forest and mountain slopes. The leaves of this unusual plant are spirally arranged with a serrated margin. Flowers are produced in dense clusters and often resemble exotic sea creatures. These plants produce abundant nectar, attracting insects and birds to the garden.

Leucadendron, also known as Conebush, is native to Southern Africa as well. Leaves are spirally arranged, but the leaves are simple, entire and often colorful, with a distinct silvery tone produced by dense silky hairs. Leucadendrons have separate male and female plants, which is unusual in the Proteaceae family. It’s long bloom time, combined with colorful leaves and bracts make this an excellent choice for dry sunny gardens.

Banksia originates in Australia, where it is found occupying a variety of landscapes and conditions. Heavy producers of nectar, Banksias form a vital part of the food chain in the Australian bush, providing food for birds, bats, rats, possums, bees and a host of insects. Banksias grow as trees or woody shrubs, and there are both erect and prostrate species available to the home gardener. Leaves are usually serrated, and  the unique flower spike is formed by an elongated inflorescence consisting of a woody axis covered in tightly-packed pairs of flowers attached at right angles. A single flower spike generally contains hundreds or even thousands of flowers. Most Banksias are yellow, but orange, red and pink also occur.

If you have a garden space that is sunny and dry, you might want to try one of these exotic plants.

A grafted tree will typically take up to 7-10 years to begin producing, but will continue to produce for over a 100 years if managed correctly.

The macadamia nut originates in the sub-tropical rainforests of the east coast of Australia in Queensland and New South Wales. The nut has always been an important source of food for Australian aborigines. Modern cultivation of the nut began on Hawaii in the 30s, then in Australia in the 60s. Now it has spread to suitable climates around the world. I have seen it in Kenya and numerous areas of Mexico. I’m curious if anyone has ever tried growing it in Mediterranean climates, such as Greece.

The tree is well-suited for cultivation in Agroforestry systems, and is uses as such in Kenya, where I saw it grown with a coffee understory.

The presence of members of the Proteaceae family (colloqually called “Prots”) in Australian tropical rainforest is a key feature that makes Australian tropical rainforests unique on a global basis. Among the members of the Proteaceae that have taken to rainforest living, some stand out more than others, even when they have not flowers. The Far North Queensland endemic Briar Oak is one such member. What is more interesting is that the leaves of younger plants totally different from those of older plants, hence the specific epithet ‘heterophylla‘. Many other rainforest Prots do this as well (eg, Athertonia, Buckinghamia, Darlingia, Grevillea, Placospermum, Stenocarpus, etc), but Musgravea doesn’t take a particularly trained eye to immediately tell it apart from the other rainforest Prots. Anyone can recognize the lobed leaves which look like giant oak leaves with very closely spaced lobes. The undersides are also silvery. When the tree matures the leaves on display are a normal-looking obovate, and can only be recognized if one is already familiar with the venation.

Unsurprisingly, juvenile plants make good ornamentals.
More on this handsome plant when it shows me the more tender aspects (flowers and fruits) of it’s personality.

Australian botanists have their lingo for members of the Proteaceae. They call them Prots. And any botanist who says that Prots are an easy group is either an incarnated Prot themselves or a genius. With this as an antecedent, I must say however, that Gevuina bleasdalei is probably the easiest Prot to identify in the field, at least if one can get a good view of the leaves. Firstly, the leaves are compound, alternately arranged and possesses toothed leaflets and a distinctively winged rachis. Moreover, the common names Blush Silky Oak and Wingleaf Silky Oak says it all. This rainforest tree is a compulsive blusher! Like most Prots, the leaves are alternately arranged and in this species the young leaf growth is a deep brown red and extremely distinctive and ornamental. The leaves also can be recognized instantly. They are compound with toothed leaflets and the rachis is distinctively winged.

“Blushing” new leaves

Flowers

The genus Gevuina is an interesting one both biogeographically and ethnobotanically. G. bleasdalei is endemic to Australia and it has a relative known as the Chilean Hazel (Gevuina avellana) of South America, which is the source of edible Gevuina nuts, a little known Proteaceous goodie which has languished in the shadow of the macadamia. The name Gevuina was in fact based on an approximation of the Mapuche word ‘Guevin’ for the species. Could our Queensland species also have edible nuts? That would be interesting to find out.

… found at Kirstenbosch Botanical Gardens, Cape Town

A common small tree of savanna areas, this Grevillea has very thin strap-like leaves with ~5 or so veins underneath. The veins form furrows inbetween them, which in younger leaves may be filled with brownish hairs. Presumably, these hairs cover the stomata and slow water loss.

This relative of the Macadamia nut tree is named after Atherton. The leaves of this rainforest tree occur in different shapes and are lobed particularly in younger specimens like many other rainforest Proteaceae. I find that the venation on the underside is the easiest way to distinguish this species from potentially confusing species. On the underside, the midrib and lateral nerves are covered in rusty brown hairs, which makes them stand out against the pale colour of the leaf undersurface in a diagnostic fashion.

The nuts are edible but they are extremely difficult to crack open. But once cracked, the white fleshed interior is revealed and this tastes deliciously like coconut. Wouldn’t it be awesome to have a Atherton Oak plantation?

A very commonly planted native rainforest tree. Like many other rainforest Proteaceaes, this species has the tendency to form lobed leaves, particularly in young specimens. In adult specimens, most of the leaves are unlobed. As such it can be mistaken for other species like Athertonia, Grevillea, Placospermum, Stenocarpus etc. Ostensibly the most distinctive character must be the fruits and the winged seeds. Field identification however probably requires a familiarity with the texture of the leaves and the venation. For instance, Stenocarpus sinuatus, a similar species when not in flower, has much more leathery leaves. Placospermum coriaceum also has lobed leaves but the leaves have a fleshier texture.

Darlingia darlingiana has a close relative in FNQ, D. ferruginea, which has rusty brown hairs on the leaf undersides and young twigs.

Back to species list

The flowers are spectacular, at times covered with bees, especially in the early morning (when I took this photo).

There are quite a few wildflowers around Tea Gardens during spring. This particular photo is of a plant known as Drumsticks (Isopogon anemonifolius). It belongs to the same family as Proteas, Banksias and Grevilleas (Proteaceae).

This particular species of Isopogon is an upright, medium sized shrub with yellow flower heads in spring and summer. They are quite a nice flowering shrub and would make a great addition to a garden in the same way proteas and grevilleas are. They also make a good cut flower for flower arrangements. Propagation is from seed.

More Tea Gardens Wildflowers at:

Tea Gardens Wildflowers

Leggi l’articolo completo su http://www.ProntoGiardinaggio.com “Grevillea Juniperina Sulphurea“

Well-composted, loosened soils that are mulched are rarely water-repellant. It’s important to use a variety of mulch types as well because different mulch types feed different types of soil microorganism – the good guys.

Soils repeatedly mulched with woodchip gradually become water repellant because woodchip suits certain fungi and their hyphae (feeding fungal threads) build up over time, reducing the soil’s ability to absorb water. Avoid this practice.

Should I use wetting agents?
Soil wetting agents and surfactants are now widely used to counteract water-repellant soils, but what are they? Do they really work? Are they harmless to people, pets, plants and the environment?

How they work
Wetting agents either improve the absorption of water by a material that would otherwise repel water, such as dry soil, or to increase the adhesive properties of a spray in order to adhere to the surface of plants. These are also known as surfactants and they work by reducing the surface tension of water.

Why not save money by using household soaps and detergents?
The Australian Standard for the biodegradability of detergents applies only to the active ingredient, not to any of the many additives they contain.

Many household soaps and detergents react with the soil and with fertilisers. The results can be fatal to plants.

Wetting agents
There are a few artificial wetting agents that are certified organic. The majority are unsuitable for organic gardens.

Conventional wetting agents are usually alcohol or petroleum distillates such as polyacrylamides. Polyacrylamides are commonly used on an industrial scale in irrigation water allegedly to improve the absorption of water by soils and to reduce soil erosion.

Wetting agents are commonly used in commercial potting mixes, since they are primarily bark based and water-repellant when dry.

Polyacrylamides and other synthetic wetting agents are prohibited under organic standards. But natural wetting agents, including soaps, saponins and microbial wetting agents are allowed in organic gardens.

Use organic-certified wetting agents which are genuinely and readily biodegradable. I make my own agar agar-based wetting agent and also use ‘Eco-hydrate’ manufactured by Organic Crop Protectants (see: http://www.ocp.com.au). ‘Eco-hydrate’ contains organic humectants and organic surfactants. Equivalent products may exist but I’m not aware of them. Let me know If you find others.

Make your own natural soil wetting agent
You can make your own soil wetting agent using the food grade thickener, agar agar (algin), derived from seaweed.

Slowly add boiling water to agar agar and stir to make a paste about the same consistency as wallpaper paste. Then dilute 250 ml of paste in 4.5 l of water. Water on to seed beds, seedlings, flower beds or containerised plants.

Like any type of wetting agent, algin solution blends most effectively when applied to already moist soil. But unlike chemical wetting agents, algin has no hidden, unexplained or harmful side effects. It’s readily biodegradable, so when transplanted seedlings have established it’s likely to have been digested.

History of chemical wetting agents
Invented in the 1950’s, there’s about 70 different types available, often pre-mixed into potting mixes and fertilisers. Pre-mixing is advocated by agribusiness for home gardening. Unconfident gardeners are often reluctant to spend money on buying them separately because they are unable to discern whether they work at all and by adding them in the factory manufacturers ‘value add’ to existing products to gain a market edge. The majority of potting mixes use artificial wetting agents and most golf courses now use them.

Research into and the evolution of wetting agents is poorly documented resulting in confusion and poor understanding of how to use them, in particular on different types of soil. Anecdotal evidence at the Royal Botanic Gardens, Sydney (1992 – 2003) indicates that they can harm the sensitive roots of ferns and the highly evolved roots of orchids and plants in the Proteaceae family.

Supporting strategies
Levelled beds will always be easier to water and less likely to shed heavy rainfall and irrigation than sloping beds.

Raising beds above ground level encourages drainage. Most moisture-loving plants prefer good or average drainage. The roots of the vast majority of land plants obtain their oxygen directly from the soil.

When soil becomes saturated all the air pockets become water-filled and roots lose their source of oxygen. In warm, wet summers roots can suffocate in waterlogged soils in 24 hours or their defence systems become compromised, consequently becoming vulnerable to attack by fungi, nematodes and bacteria. Waterlogged soil treated with wetting agents can become deadly to plants.

Compacted soils, especially clay and loamy soils, are always hardest to water. Dig or loosen soil to alleviate compaction, annually adding gypsum (clay breaker) to clay or loamy soils to encourage what’s known as a ‘crumb structure’ that allows air and water to move more freely.

Soils affected by dryland salinity, such as parts of western Sydney, lose their natural crumb-like structure making it harder for air pockets to occur in the soil. Raised beds, compost-rich, well-dug soil that is annually conditioned with gypsum helps to make soil healthy and water absorbing.

Unanswered concerns about the use of artificial wetting agents and water crystals

1. Some of these compounds are derived from, or contain traces of, carcinogenic acrylamides.
2. The interaction of some wetting agents with other compounds, such as pesticides (including Persistent Organic Pollutants or POPS) and fertilisers in soil and waterways is not adequately understood for broad scale use.
3. The breakdown products of some wetting agents:

• Are persistent in the environment;
• Ultimately retard water absorption by soils;
• Enter the food chain directly and indirectly;

4. Field observations are that their breakdown products could:

• Cause adverse biological effects by interfering with the endocrine system and disrupting the physiological function of hormones in animals, including humans;
• React with salts or bauxite in soil;
• React with heat, such as from bushfires, resulting in toxic compounds;
• Have a plasticising effect on surrounding soils resulting in lower water absorption rates and encourage soil erosion;
• Harm the roots of ferns, orchids and Proteaceae;

Meet the family of wetting agents and surfactants:
Wetting agents, which include surfactants, reduce the surface tension of water so that it spreads and is absorbed by dry soil and potting mix. They help water transfer from particle to particle. They are widely used to enhance the effects of pesticides.

There are four different types of surfactant:
Nonionic Surfactants are the most commonly used wetting agents in horticulture. When used properly they do no direct harm to plants. Applied at too high a strength plants may be harmed. Research is investigating how to use their ability to harm zoospores (fungal spores that swim through soil moisture) as fungicides.

Anionic Surfactants enhance foaming and spreading properties. Shampoo for hair contains sodium or ammonium laurel sulfate. In horticulture using an anionic surfactant can cause problems with sprayers that have an agitator, or where foam could disrupt water flow or the action of pumps.

Cationic Surfactants are often very toxic to plants as they can disrupt membrane ion balance. They are not widely used for pest control.

Amphoteric Surfactants are rarely used in horticulture and when used are added to pesticides.
Wetting Agents are commonly added to potting mixes, which often contain a high proportion of pine bark. Potting mixes sometimes have unnecessarily high amounts of wetting agents.
They work much like surfactants and include, or are based on, polyoxyethylene esters and ethoxy sulphates. Applied at too high a strength they become toxic to leaves and roots. Weather and temperature can affect plants similarly after their use especially if they’re growing in bark or peat-rich media.

Other wetting agents
Penetrants. Penetrants dissolve or penetrate waxy layers on leaves and allow other chemicals to interact with plant or insect tissue, such as in pesticides.

Thickeners which reduce spray drift. They may contain polyacrylamide, polyethylene polymers, polysaccharides or vegetable oils. Applied at too high a strength these products can burn plants or block spray nozzles.

Emulsifiers. Emulsifier agents allow petroleum-based pesticides and water to blend.

Spreaders and stickers. Spreaders help pesticides to cover plants evenly, whereas stickers improve the adhesion of pesticides. Stickers are a diverse group and may contain fatty acids, latex, alcohols, plant oils or inorganic oils. They can harm rough-leaved and hairy-leaved plants, annuals and herbs.

Oils. There are two types of oil: plant and petroleum oils, generally used to suffocate sap-sucking and certain chewing pests.

Alkyl polyglucosides. These are environmentally-safe modified sugars used in genuinely biodegradable detergents and various pesticides, some of which are acceptable for use in organic gardening.
Jerry Coleby-Williams

References: The Evolution of Soil Wetting Agents for Managing Water Repellency in Soils.
D. Moore, S. J. Kostka, M. Franklin, L. L. Lennert, and R. A. Moore. Aquatrols, 843 East Parkway, Salt Lake City, UT 84106