Chamelaucium and its Relatives - Propagation

Introduction

Propagation of plants in the Chamelaucium Alliance from seed is often unreliable and propagation by cuttings is the preferred method. This also enables plants with desirable characteristics of form or flower colour to be perpetuated. Some species, particularly Darwinia and some Verticordia, have been successfully propagated by grafting.

Seed

While germination of seed of this group of plants is not impossible, seed of many species is often difficult to obtain because, in many cases, the seed is released from the mature capsules when ripe, making it difficult to collect. Germination data on many species is also limited or not available. Seed of some species of the following genera can usually be obtained from commercial suppliers, and some others may be available from time to time.

  • Baeckea, Sannantha, Babingtonia and (presumably) related plants such as Kardomia - usually germinate reliably without pretreatment.
  • Calyrtix - the best results seem to occur if the seed is pre-germinated prior to planting into seed raising mixes. Pre-germination involves placing the seed in an enclosed container together with moist paper or vermiculite until the root is seen emerging from the seed. This may take 2-3 weeks or more (refer to ANPSA's Plant Propagation Pages for more information).
  • Chamelaucium - germination unreliable.
  • Hypocalymma - usually germinates reliably without pretreatment.
  • Thryptomene - usually germinates reliably without pretreatment.
  • Verticordia - germination unreliable.

Another method that has been successful for at least some species is the use of smoke or "smoked water" as a pretreatment. This has been successful in the germination of species of Astartea, Baeckea, Calytrix, Hypocalymma and Verticordia and may have practical application for the home propagator. Further information on this procedure is available in the article Smoke Stimulates the Germination of Many Western Australian Plants (see Further Information) and from the Regen 2000 web site.

Cuttings

Many plants in the Chamelaucium alliance are readily propagated by cuttings using hardened, current-season's growth. Cuttings about 75-100 mm in length, taken in January in southern Australia would normally be suitable with the leaves carefully removed from the lower two-thirds. "Wounding" the lower stem by removing a sliver of bark and treating with a "root promoting" hormone both seem to improve the success rate.

Grafting

Because some of the most spectacular members of the Chamelaucium alliance are native to the Mediterranean climate of south-west Western Australia, attempts at cultivation in humid areas of the east coast are not always successful. Particularly difficult are the spectacular 'feather flowers' (Verticordia species) and the darwinias in the 'mountain bell' group. To try to expand the range where those plants can be successfully cultivated, some work has been carried out on the grafting these species onto hardy rootstocks.

This work has been successful to a limited degree. Darwinia citriodora seems to be the root stock of choice for grafting of Darwinia and Verticordia species but only in districts where D.citriodora is reliable (despite the fact that D.citriodora is itself a species from the south-west, it is hardy in temperate areas of the east coast). Grafted plants of species such as D.meeboldii, D.macrostegia and D.oxylepis are now commonly available at specialist native plant nurseries.

The hardiness of Chamelaucium uncinatum varies not only according to climate but also according to clone, whith some forms being noticabaly more hardy than others. For example, the common pink flowered form is much hardier than the deeper coloured forms in temperate and sub-tropical areas. Grafting of less hardy forms onto a rootstock of the hardy, pink flowered form should enable those less hardy forms to be cultivated more widely. Other rootstocks for Chamelaucium that have been tried with some degree of success include Darwinia citriodora, Kunzea flavescens, Kunzea ambigua and Leptospermum petersoni.

There is still scope for enthusiastic amateurs to carry out rootstock trials for plants in the Chamelaucium alliance. There are two factors to be considered when selecting suitable rootstocks:

  • Hardiness of the stock - the selected stock needs to be reliable in the area where the grafted plant is to be grown.
  • Compatibility between stock and scion - the closer the relationship between the stock and scion, the better the chance of success. Stock and scion of the same species is ideal, stock and scion in the same genus is often successful and stock and scion in closely related genera may also be suitable if other options are not viable.

General Propagation

Further details on general plant propagation can be found at the Society's Plant Propagation Pages.


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