Odontonema tubaeformeSometimes referred to as Odontonema cuspidatum (and I am not really sure which is the currently correct name), this is a semi-tropical shrub from Central America which can grow to 2m tall, with large, lush, shiny leaves. In late summer and autumn it produces plumes of blood red, glossy spikes of flowers, which almost look as if they are made of some sort of plastic. The flower stalk is purplish-black, providing a vivid contrast. It is very long flowering for a period of several months. It is sometimes known as fire spike or red justicia, and was once classified as a Justicia.
Hot-coloured border in the former garden of Alida Gray in Sydney; Odontonema tubaeforme in foregroundLike Justicia, it belongs to the Acanthaceae family, which contains a large number of shrubby perennials suitable for the Sydney climate. Many of these, like this one, enjoy growing in a shady position amongst bold foliage plants such as elephant's ears (Alocasia) and bird's nest ferns (Asplenium australasicum). It tolerates heavy, part or dappled shade. Odontonema associates well with other hot-coloured flowers which grow in a shaded spot, such as shrub and cane Begonia, Salvia miniata, Salvia splendens and bromeliads with red centres or red flower spikes (including some of the Vriesia cultivars). It can also echo red tints in nearby autumn-colouring trees.
The mass of the plant's foliage provides a good screen at the back of borders for the whole year round. In mid-August, it should be cut back pretty hard and given some fertiliser. It will grow in quite ordinary dry soil but will be grateful for some mulch and some occasional water. Overhead tree cover will protect it from mild frosts but it is not a plant for very cold areas. It strikes readily from cuttings. Note that it may spread from its base to form something of a thicket (although this has not happened with any of my specimens as yet), but this can be of use in a dry, shaded area that requires a screen.
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