Surely the best known protea, prized worldwide as a magnificent cut flower and in South Africa honoured as the national flower. Protea cynaroides is a woody shrub with thick stems and large dark green, glossy leaves. Most plants are one metre in height when mature, but may vary according to locality and habitat from 0.35 m to 2 metres in height.
Protea cynaroides can be propagated from seed or from cuttings. The stems have to be thick and strong to carry the heavy flower heads, this makes the taking of cuttings quite difficult, but good colour forms or cultivars have to be propagated from cuttings. Cuttings are made from semi-hardwood, 6-10 cm long, of the current season's growth. The cuttings are dipped for about four seconds in a rooting hormone solution and placed in a growing house with bottom heat (25ºC) and intermittent mist. The rooted cuttings are potted up when the roots are well developed and planted out in the late autumn in South Africa, or in spring in colder areas.
The large nut-like seeds have to be treated during storage with a systemic fungicide with the active ingredient of metalaxyl (Apron) and sown from the middle of March, when the day temperature starts to drop. The seed is sown in open seedbeds, in a light, well drained soil and covered with a layer of sand (about 1 cm or 1 1/2 times the size of the seed). The bed is then covered with a grid against the attacks from birds and rodents. The seed will germinate three to four weeks after sowing. The plants are generally about four or five years old from seed before they flower. On older plants the side shoots tend to be quite short, so to encourage the development of new shoots and long stems, the stems bearing old flower heads should be cut back to ground level. Older plants also tend to become woody and should be cut back to ground level, where they will sprout again from the thick underground rootstock.