Waratah and its Relatives - Propagation

Introduction

Propagation of waratahs and their allies can be carried out by both seed and cuttings. However, with such a diverse range of species, the success of each method can be variable. Because relatively few members of the Embothrieae are widely grown, there is a lack of knowledge of the best propagation methods for many species.

To maintain desirable characteristics of a particular plant, vegetative propagation (eg. cuttings or grafting) must be used. This also applies to propagation of named cultivars.

As far as is known, grafting has not been used to any great extent with this group of plants.

Seed

As seed is shed annually, plants need to be kept under observation and seed capsules collected when they first begin to open.

Provided the seed is viable, germination of commonly cultivated members of the Embothrieae is usually reliable and no pretreatment of the seed prior to sowing appears to be necessary. There is some evidence that germination is most successful with fresh (current season) seed - this is possibly especially relevant for species native to rainforest areas.

"Damping-off" of seedlings is often mentioned as a potential problem with the NSW Waratah and may be a problem with related plants as well. Damping-off is a fungal disease which causes rotting of the stems of seedlings, particularly if the environment in which the seedlings are kept is over-wet. The disease can be controlled with an appropriate fungicide if it becomes a serious problem.

Seed can be sown in normal seed raising mixes and seedlings could be expected to appear in anything from 2-8 weeks.

Cuttings

Propagation from cuttings is a reliable method for many species in the Embothrieae. It is often preferred over propagation from seed because of both the scarcity of seed and because of the fact that cutting-grown plants will usually flower at an earlier age than seedlings.

Cuttings about 75-100 mm in length with the leaves carefully removed from the lower half to two-thirds seem to be satisfactory. "Wounding" the lower stem by removing a sliver of bark and treating with a "root promoting" hormone both seem to improve the success rate. No special propagating mixes or treatments are required.

Grafting

As noted above, grafting has not been used with members of the Embothrieae to any great extent. However, there may be some scope for using grafting with species such as the firewheel tree (Stenocarpus sinuatus) and tree waratahs (Alloxylon spp.). These can take many years to flower when grown from seed and grafting material from mature flowering plants onto seedlings of the same species may produce plants that flower at an early age. Furthermore, the plants may flower when smaller, rendering the blooms more conspicuous. This would be especially desirable in the terminally flowering tree waratahs.

The Society would welcome advice from anyone who knows of any use of grafting with this group of plants.

General Propagation

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


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