Waratah and its Relatives - Cultivation

Introduction

Like most groups of plants, some members of the Embothrieae have proved to be easy to grow in cultivation over a wide range of climates, while others have proved to be a cause of frustration. The development of Waratah cultivars has gone some way to addressing this.

As a general rule, members of the group require the following combination of conditions:

  • Excellent drainage - they will not tolerate waterlogging
  • Assured moisture (especially in summer, in contrast to most other Proteaceae)- but freely draining
  • Good light - at least half sun, though many species prefer some shade while young.
  • Soils with at least some nutrient retaining potential, either from thick mulching or some degree of clay content (eg sandy to clay loams).

How strictly one needs to adhere to this regime varies from species to species.

  • Waratahs (Telopea species) and Tree Waratahs (Alloxylon species) are the Australian representatives of the subtribe Embothriinae. All have striking red (sometimes white or yellow), showy flowers and deep green foliage, though the latter genus are far larger in size (10-30 metres high in their natural rainforest habitat). All can be temperamental and somewhat fussy when young (first two years or so), though usually become hardier once they have become established.

    In southern New South Wales and the ACT, several Waratah hybrids have been developed, notably Telopea "Braidwood Brilliant", "Canberry Coronet" and "Shady Lady". These tolerate more shade, frost and suboptimal drainage than that required for their Telopea speciosissima parent. The other parents of these hybrids are the two species from the southeastern corner of Australia; Telopea oreades (for "Shady Lady") and T. mongaensis (for "Braidwood Brilliant" & "Canberry Coronet").

  • Lomatias have proven fairly hardy in cultivation as long as they get sufficient moisture - this is especially important if they are being grown in full sun. The genus was introduced to England in the 19th Century but is uncommonly cultivated there (or for that matter in Australia) now. In general they have white flowers which are less showy overall than their kin but instead are fascinating foliage plants with a large variety of leaf shapes seen, sometimes on the one plant, which along with their hardiness make them worthwhile garden subjects.

  • In general, members of the other genera are more forgiving on gardeners; some are even hardy enough to be used as street trees (Stenocarpus sinuatus and Buckinghamia celsissima) also far to the south of their original subtropical or tropical habitat. Though few have flowerheads to match the spectacle produced by the waratahs, many are beautiful foliage plants with interesting and unusual floral forms as well. Several, however, are spectacular in their own right - a well grown ivory curl tree (Buckinghamia celsissima) in full flower will never fail to attract attention and the firewheel tree (Stenocarpus sinuatus) is arguably one of the most spectacular flowering plants in the world.
   Proteoid roots
   Proteoid roots can often be seen by carefully removing a proteaceous plant from its pot, as shown here.
Photo: Brian Walters

As might be expected with such a diverse group of plants, foliage characteristics are also quite variable. The range of foliage shapes in the genus Stenocarpus is particularly interesting and a number of species are worth growing for these characteristics alone. For example, S.cryptocarpus can produce immense, divided leaves well over a metre in length while the fern-like, juvenile leaves of S.davallioides are outstanding.

Some of these plants of rainforest origin prefer a degree of shade when young, and indeed may be used in brightly lit areas indoors for a time. This can be a great way to highlight those species with attractive foliage.

Like most members of the Protea family, the Embothrieae have a distinctive root system ("proteoid roots") consisting of tight groupings of many small "rootlets". These are believed to enable the plants to more efficiently take up nutrients from the nutrient-deficient soils where many of the species occur naturally. In cultivation this means that the plants can be adversely affected by fertilizers, particularly phosphorus. It is generally recommended that Proteaceae be fertilised only with low-phosphorus, slow-release fertilisers or not be fertilised at all.

Currently, only few members of the Embothrieae are seen commonly in cultivation. Hopefully this will change in the future. However, several (such as the three Strangea species) are probably of limited horticultural merit and will probably only be grown by enthusiasts and by Botanic Gardens.


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