The best-known species in this genus is Telopea speciosissima, which has bright red flowers and is the New South Wales (NSW) state emblem.

The key diagnostic feature of Proteaceae is the inflorescence, which is often very large, brightly coloured and showy, consisting of many small flowers densely packed into a compact head or spike.

Species of waratah boast such inflorescences ranging from 6–15 cm in diameter with a basal ring of coloured bracts.

Within the Proteaceae, their closest relatives appear to be the genera Alloxylon (tree waratahs), Oreocallis and Embothrium, a group of generally terminal red-flowering plants that skirt the southern edges of the Pacific Rim.

[3] There are two main branches, with one being the species pair of T. speciosissima and T. aspera, with the other lineage giving rise to T. truncata first, then T. oreades and T.

[4] The speciosissima-aspera lineage (clade) has two synapomorphies—distinguishing common characteristics presumed not present in ancestors—leaves with toothed margins, and large red involucral bracts.

The truncata-oreades-mongaensis lineage has flowers that open from the centre to the edge of the inflorescence (basitonic) rather than the reverse (acrotonic), which is a feature of the speciosissima-aspera clade and more distant relatives.

The natural distributions of the five species of Telopea are all confined to east coast regions from northern New South Wales to Tasmania.

Overseas, New Zealand, the USA, South Africa, and Israel are all also able to grow waratah with varying degrees of success.

It was introduced to England in 1789 but cannot survive English winters out of doors except in the south-west coastal regions, and it rarely flowers in glasshouses.

Some progress has been made in the 20 years since then with several cultivars being commercially grown mostly in areas to the North and South of Sydney and in the Dandenong Ranges in Victoria.

Rootstock and scion combinations are used for many woody perennials to provide the necessary mix of floral or fruit characteristics and cultural requirements.

Tissue culture is very labour-intensive and would likely only be used in the case of rapidly increasing the number of plants from limited or valuable material.

The overall cultivation of the waratah as a single process is a tricky one as flowering time, number and quality are easily affected by changes in the plant environment.

As an Australian native the waratah is a sturdy plant well adapted to coping with harsh environments and low rainfall.

This coincides with the observation that fertiliser application immediately after transplant of waratahs in the field often leads to high mortalities.

Earlier work (1963) on related species, had indicated that fertiliser application may hasten maturation and give early flowering.

Pruning is a very important consideration for the commercial growth of waratahs in the effort to design a shape for the plant that will encourage the maximum production of saleable blooms.

Damping off is a condition that causes the death of seeds or seedlings facilitated by a number of different fungal pathogens.

Bract browning has been a major restraint to financial returns due to reduced cut flower quality.

The addition of shade cloths to crop management strategies has been shown to reduce levels of excessive light and has significantly minimised financial losses due to the reduction of occurrence of bract browning.

Once plants have reached waist height cases should be analysed individually to determine the best method of weed control.

In New South Wales the most destructive pest to waratah crops is the macadamia twig girdler (Neodrepta luteotactella).

What is used for the borer should also control lesser pests such as white scale, which is common in the natural state, and Macadamia leafminer (Acocercops chionosema).

A problem for production that emanates from within the plant is the high amount of genetic and therefore morphological variability present in the flowers produced.

In many genera of Proteaceae the inflorescence is very large and showy, often in bright colours, consisting of many small flowers densely packed into a compact head or spike.

Floral induction involves physiological processes in the plant that result in the shoot apical meristem becoming competent to develop flowers.

Florigen is produced in the leaves in reproductively favourable conditions and acts in buds and growing tips to induce a number of different physiological and morphological changes.

Flowering tends to vary with geographic location and climatic differences, occurring from early August in coastal Queensland and up to December in Tasmania.

In 2009, the Premier of New South Wales, Nathan Rees, commissioned a state logo based on the floral emblem.