Western Australia has a plethora of horticultural species which are unique. The south-west region is particularly rich in plants that are not found anywhere else. One such genus is Chamelaucium which belongs to the Myrtaceae family (myrtles). There are around 30 species in this genus. They are generally small to medium shrubs with a fairly open habit. The leaves are narrow and the star-shaped flowers are similar to those of the tea-tree (letrospermum).
By far the best known of the species is Chamelaucium uncinatum or Geraldton wax. Although Geraldton is well north of Perth, the Geraldton wax grows across a wide area of sandplain country. It is more adaptable to those regions with dry summers but is reasonably hardy under most climatic conditions bar the humid tropics.
The Geraldton wax is widely grown in domestic gardens. It is also grown extensively both in Australia and overseas for the commercial cut flower market. In the wild, it is found growing in well-drained gravelly soil in rather dry conditions. It is sometimes known as wax flower and has a small, star-like flower. It makes an attractive container plant and has low moisture requirements. It will tolerate light frosts and suited to sandy soils. As a cut flower, it is very eye-catching and long-lasting (well over a week).
It grows to 2.4 metres with up to a 5 metre spread. The leaves are narrow and up to 40mm long. When crushed, they give off a pungent odour. The flowers are circular in shape with a 15 to 20mm diameter. The flowering season is from late winter well into summer. In the wild, the flowers are pink, varying from pale to a deep pink.
The Geraldton wax should be planted in well-drained soil in partial or full sun. It will withstand extended dry periods.
Constant tip pruning will encourage a bushy, compact shape and once a year it can be cut back by a third. As these shrubs may spread to 5 metres, they are a good choice as a screening plant or can be clipped to form an attractive hedge.
Cultivars have been developed and there is now greater variety in the colours available. The pink-coloured varieties tend to be hardier than other colours. Dwarf forms have also been developed which are very attractive. Cultivars need to be propagated from cuttings if they are to retain the characteristics of the parent. Flower colour, length of stem, frost and drought tolerance are all characteristics which may be altered in cultivars. Flower colours now include pure white, purple, mauve or pink or even combinations of these.
Some of the cultivars are:
* University - purple-red flowers
* Vista - pink flowers
* Album – white flowers
* Jubilee – pink flowers
* Purple Pride – purple flowers
Another less well-known Chamelaucium is Chamelaucium floriferum. Floriferum comes from the Latin ‘flos’ – a flower and ‘ferum’ – bearing. This refers to the massed nature of the floral display. Chamelaucium floriferum has the common name of Walpole Wax and grows to 3 metres high. Like the Geraldton wax, it has linear, narrow leaves which are highly aromatic if crushed.
It is a decorative species and provides a profuse display of open-petalled flowers of about 1.5cm diameter. The flowering season is from August to November. The flowers are initially white then age to pink or purple. It is a relatively hardy species and responds well to pruning. It is grown for the florists’ trade.
Chamelauciums have a reputation as being hard to grow but such is not really the case. They certainly do not do well in the humid tropics and some may be short-lived but if grown in well-drained positions in a sunny area, they can last for years. They are difficult to propagate from seed. Cuttings from the current season’s growth will generally strike quite easily.