The Red or Scarlet Flowering Gum grows to around 10m tall. It is an evergreen tree whose deep green leaves form a thick canopy. It is one of the best of the Australian native shade trees. Its natural habitat is on the south coast of Western Australia between Denmark and Walpole with an isolated population east of Albany.
Under less than ideal conditions, the tree may be straggly and somewhat nondescript but it is transformed at flowering. The prolific blooms may vary from scarlet and crimson, through oranges and pinks to the most delicate pale pink shade.
In 1860 it was given the name of Eucalyptus ficifolia but this was changed in the 1990s to Corymbia ficifolia. They have become popular as a cultivated species and grow well in most areas of Australia apart from tropical and mountain zones. There are some fine examples growing on sand plains around California. The trees are what is known as ‘second line salt tolerant’ meaning they grow well a few kilometres inland from the sea in warm coastal conditions.
The tree is of medium size with rough, grey-brown bark, lance-shaped foliage and a spreading crown of roughly 5 metres. The leaves are 70 to 140mm long. The buds are on long stalks and appear in clusters of three to seven. The large, woody fruits are barrel-shaped but may contract slightly at the opening. Enormous terminal clusters of, usually, scarlet to orange flowers appear in late spring to summer.
In sandy conditions, it has a tidy, rounded shape and elegant foliage. In heavy clay soils, where drainage is not so good, waterlogging manifests itself by weak, spindly growth and areas of die-back throughout the canopy. Once established the tree is tolerant to both drought and frost.
The red-flowering gum is so spectacular that it has become a favourite for street plantings, parklands and home gardens and is now one of the most commonly grown ornamental eucalypts. Hybrids (in particular between Corymbia ficifolia and Eucalyptus ptychocarpa [swamp bloodwood]) have been developed for the home garden. Corymbia ficifolia may also be grafted onto understocks. Such grafting reproduces the exact flower colour as well as giving earlier flowering, better disease resistance plus, generally, better performance in heavier, wetter soils.
Because the hybrids are grafted, it is possible to ‘fix’ the colour of the individual trees. Plants can also be raised from seed from autumn to early summer. Plant in any free-draining seed mix. When planting from seed, there is no guarantee that the resulting tree will have the same colour flowers as the parent tree.
For best results, the red-flowering gum requires full sun and good drainage. They respond well to regular watering during summer and light applications of a general fertiliser. The trees can be hard pruned if necessary. Light pruning of grafted trees for the first few years will prevent them from becoming top heavy.
Many nurseries sell grafted plants, dwarf forms and hybrids. Some of these varieties may have larger flowers and are suitable for containers or for smaller gardens.