The protea family (Proteaceae) includes a wide range of ground covers, trees and shrubs that often make superb garden plants. While some of the species are frost-tender, they are in all other respects remarkably resilient plants that often thrive in situations where others would rapidly succumb. Poor soils and hot dry positions that scarcely seem capable of supporting life are often ideal for Proteaceae. If any plants could be said to thrive on neglect the proteas can.

Proteas (the term is often used collectively as well as for the genus itself) are a variable group. Indeed, the family was named after Proteus, a Greek god capable of changing his shape at will. It includes some 60 genera and 1400 species of Southern Hemisphere plants, the bulk of which are native to southern Africa and Australia with the remainder coming from South America and many of the Pacific islands, including two species (Knightia excelsa and Toronia toru) from New Zealand.

There is an enormous variety of foliage among the proteas. It is almost always evergreen, but may be needle-like, as with many grevilleas; long, narrow and serrated like that of Dryandra formosa; or rounded and leathery like the leaves of Protea cynaroides. Some genera, particularly Leucadendron, include species with brightly coloured foliage, the intensity of which varies with the season. Leucadendron stems retain their colour for weeks when cut and are an important part of the cut flower industry.

Protea flowers are composed of clusters of narrow tubes that are often curved. These 'spider' flowers are seen at their simplest in the two native species and some of the grevilleas. In many cases what appears to be the flower is actually a bract of brightly coloured leaves surrounding the true flowers. The most impressive example of this is the dinner plate-sized flower head of Protea cynaroides. The flowering season also varies; many proteas and grevilleas flower in winter, while leucospermums tend to flower in summer. With careful selection it is possible to plants in flower all year round.

The flowers often contain large quantities of nectar that many birds relish. Some species have very sticky flowers that will trap visiting insects, especially bees an this slightly sinister side of the flower appears to serve no particular purpose.

The South African and Australian Proteaceae tend to be at their best in warm, dry conditions and often thrive in coastal areas. Inland, unseasonable early and late frosts often kill all but the hardiest specimens. The South American genera tend to be hardier and prefer somewhat damper conditions. Embothrium in particular, can withstand hard frosts and is grown over most of the country. But where winter temperatures regularly drop to -6°C or lower, most proteas require frost protection.

Cultivation

Other than a suitable climate, the key to success with proteas is establishing the right soil conditions. The protea family is mainly adapted to mineral based soils that drain very quickly and which often have low nutrient levels. These soils tend to be moderately acid and are often especially low in phosphates.

Good drainage is absolutely essential. Rich loams and heavy clays do not make good protea soils. If you have a heavy soil do not try to improve it by adding sand or shingle as this will often make the problem worse; the soil binds with the sand and shingle and sets like concrete. Instead add more humus. Proteas would not appreciate the rapid burst of nutrients from a rich compost so the humus used should be fairly low in nutrients. Natural leaf mould and rotted pine needles work well. To avoid these materials compacting down into a poor draining thatch, incorporate about 50% fine shingle grit by volume and combine the mix with the existing soil.

Most proteaceous plants come from areas with low rainfall or where the rains are strictly seasonal. Many are coastal plants although most of the South African genera include alpine or sub-alpine species. Knightia from New Zealand and Embothrium from Chile are exceptions; they usually occur away from the coast, in areas where rainfall is quite high and not seasonal. Nevertheless, they still demand excellent drainage.

Although proteas are remarkably resilient and not difficult to grow there seems to be some common myths regarding their cultivation. Like most myths these have some basis in fact, but they can be misleading.

Myth 1: feeding proteas will kill them.

That's not strictly true. Proteas need nutrients just like any other plant, but their are a little more exacting than some. It's not fertiliser that does the damage but high phosphate levels and intense bursts of nutrients that lead to overly rapid growth. Avoid most general garden fertilisers, fresh animal manures and anything with added superphosphate. Because proteas will tolerate poor soils, it is often easier not to feed them rather than risk damage, but you'll certainly get better results if you apply a slow release, low phosphate fertiliser in late winter and mid summer. This will keep the plants growing slowly but steadily; any bolting into growth tends to weaken them.

Myth 2: proteas only grow near the coast.

Not true. Many proteaceous plants come from inland areas. They will tolerate salt breezes but there is no general preference for coastal conditions.

Myth 3: proteas like wind.

That's also not entirely true. Proteaceous plants do not tolerate wet foliage or high humidity for long periods and in areas prone to these conditions extra ventilation will help reduce the incidence of fungal diseases. However, most proteas have brittle branches that snap or split in strong winds so there's no reason to presume that they prefer windy locations.

Myth 4: proteas need a hot sunny position.

Yes, most Proteaceae prefer full sun or something near to it. But that doesn't necessarily mean the hottest, most baked position you can find. Although they will survive severe conditions once established, extreme heat and drought will cause damage, especially to young plants. Shade from the hottest sun will prolong the flower display and, provided the drainage is good, occasional deep watering is also recommended.

Myth 5: proteas are short-lived.

Some are and some aren't. Old plants are normally removed long before the end of their natural lives because they tend to become rather woody and untidy. You can generally reckon on a useful lifetime of at least 8 years for Leucadendron and Leucospermum, and around 12 years for Protea. However, large species, such as Grevillea robusta and Banksia integrifolia, may continue to be effective garden plants for several decades.

Planting

Most proteaceous plants are sold in containers and are ready to plant right away. However, the best planting time depends on your climate. Autumn or winter is best in mild areas as this is when moisture requirements are at their lowest, while spring is the preferred time if regular frosts are expected as this allows the young plants to get well established before having to endure winter conditions.

Start by digging a hole at least twice the size of the plant's container, this large volume of loose soil will encourage good root development.. Additional drainage material can be added to the hole if necessary, otherwise planting is just a matter of removing the plant from its container, loosening any spiralling roots before placing in the hole, then refilling the hole and firming the plant into position. Large specimens will require staking to prevent wind damage.

Cut flower use

Many proteaceous plants make excellent long-lasting cut flowers. Leucadendrons in particular are widely planted solely for the purpose of providing material for floral decorations. Protea, Leucospermum, Banksia and Serruria flowers can all be used to make impressive large arrangements while the less dramatic blooms of Grevillea and Isopogon are better suited to more dainty work.

Some flowers, particularly goblet-shaped Protea flowers dry well although they do tend to disintegrate rather suddenly after a few months. Other genera such as Banksia and Leucadendron produce seed heads or cones that can be used in dried arrangements.

Pruning

Most proteaceous plants need occasional trimming and tidying. This may be to improve their growth habit or to remove old flowers or seed heads that have become dry and unsightly.

How far to cut back is the usual question. This varies with the genera, although as a rule only light pruning is recommended as there is a general reluctance among proteas to reshoot from bare wood. Of the common genera Banksia and Grevillea will withstand hard trimming, as will Leucadendron, Telopea and Mimetes, but pruning of Dryandra, Leucospermum, Serruria, Paranomus and most Protea species should be restricted to a light annual trimming.

The best time to prune is usually immediately after flowering unless you want to leave a few seed heads to mature for use as dried decorations. In areas where there is the possibility of frost damage, it is advisable to leave pruning autumn and winter-flowering plants until spring.

Container Growing

Some proteaceae can make good container plants, but you will have to be careful with your choice of potting mixes and fertilisers. Potting mixes need to be very free draining and often benefit from added coarse material such as shingle chips or pumice. Bark based mixes seem to work well but some growers feel they produce too much ethylene, which may harm the plants in the long run. Many commercial growers use soil based mixes and they generally prefer relatively poor and gritty volcanic soils.

Even plants with low nutrient demands will eventually exhaust their potting mix, so you will have to apply fertiliser occasionally. Use mild liquid fertilisers or special low-phosphate slow release pellets. Provided you are cautious the plants should respond well.

Propagation

Proteas can be frustratingly difficult plants to propagate. Fresh seed often germinates well only for the seedlings to collapse after a few weeks. This is usually due to a fungal disease that blackens the foliage and eventually kills the young seedlings. Regular fungicide applications are important. Prick out the young seedlings into a coarse, free draining, unfertilised potting mix once they have their first true leaves.

Cultivars and selected forms must be propagated vegetatively. The usual method is firm semi-ripe cuttings in late summer and autumn. The success rate varies markedly; some cultivars, such as Leucadendron 'Safari Sunset', strike quite easily while many others may be virtually impossible without professional equipment.

Pests and Diseases

Grown under the right conditions proteaceous plants are relatively free of pests and diseases, or rather they're not attacked by anything out of the ordinary. The most widespread problems are leaf roller caterpillars and scale insects, which can eventually lead to sooty mould.

When growing proteas from seed you will doubtless lose some to the fungal disease mentioned above. This disease, which appears to be a type of damping off, can sometimes also attack more mature plants. It appears to be far worse in excessively wet conditions or after long periods of high humidity. Good ventilation and avoidance of overcrowding are effective preventatives and regular spraying with fungicides may control the problem.

Common genera

Many of these plants are not widely available at garden centres, although specialist growers would consider them to be just the most common genera and are likely to stock others as well. All of the species and genera covered here are evergreen unless otherwise stated.

Aulax

This is a South African genus of small to medium sized shrubs. This genus and Leucadendron are the only dioecious (separate male and female plants) members of the Proteaceae. Seed of all three species, Aulax cancellata, Aulax pallasia and Aulax umbellata, is available but only Aulax cancellata is commonly planted. It grows to 1.5-2m × 1m and has fine needle-like leaves. In spring, female plants produce red edged yellow flowers that develop into red seed cones. The catkin-like male flowers are yellow, as are those of Aulax pallasia and Aulax umbellata, the female flowers of which are not very showy. Aulax pallasia grows to about 3 m and Aulax umbellata about 1.5m. All are hardy to about -5°C and are usually raised from seed.

Banksia

An Australian genus of about 60 species, ranging in size from ground covers to medium-sized trees. The flowering season is primarily from late winter to late spring and most species have cylindrical cone-like flower heads composed of densely packed filamentous styles radiating from a central core. Creamy yellow to light golden-yellow is the predominant colour range, although a few species, such as Banksia ericifolia and Banksia praemorsa, have golden-orange flowers and those of Banksia coccinea are red. Most species have narrow serrated leaves that are mid to deep green above and silvery grey on the undersides but Banksia ericifolia has fine needle-like leaves. Leaf size varies from very small up to the 50cm long leaves of Banksia grandis. Hardiness varies with the species, some are quite frost tender but some will tolerate -10°C.

Relatively few are seen in nurseries but the seed of most species can be obtained from Australia. Banksia ericifolia and Banksia integrifolia are the most widely grown and are also the hardiest of the common species, both withstanding -10°C once well established. There are hardly any cultivars or selected forms of Banksia in cultivation. Species may be raised from seed and most will also strike quite freely from semi-ripe cuttings.

Dryandra

An Australian genus of around 60 species of shrubs ranging in height from about 1-4 m. Most have narrow, mid to deep green leaves that are often very long and narrow with sharply toothed edges. The rounded flower heads, which appear from mid winter, are usually light to bright yellow. The most common species is Dryandra formosa, which grows to about 3m and is hardy to around -5°C once established (most of the other species are less hardy). Dryandras are superb long-lasting cut flowers and some will also dry well. They will grow on extremely poor soil and generally react badly to most ...