About twenty species of evergreen shrubs or small trees belong to the genus Cordyline australis or Cordilinea, widespread in Asia, Australia and South America, as well as numerous cultivars. These plants, used only in apartment in Europe, develop a short erect stem, from which branch some branching, facing upwards; at the apex of the branches a broad tuft develops, consisting of long leaves, often with a papyrus consistency. The leaves of cordilinea can be of various colors, from dark green to light green, often variegated; there are also varieties with pinkish or purple-brown leaves. In nature the adult specimens produce small spikes of whitish or light blue flowers; the specimens grown in pots hardly bloom and generally remain fairly small in size, less than one meter in height, while in the wild the cord lines can reach two to three meters, depending on the species. The most common species are Cordyline australis, with thin, arched leaves; C. terminalis, with broad, slightly leathery leaves.
The plants of Cordyline australis fear the cold, and generally prefer winter temperatures above 10-15 ° C, although in fact they could withstand for short periods slightly lower temperatures. They are grown in the apartment, choosing a luminous position; in fact the cordilinea plants develop without problems in not too bright places, but the color of the leaves tends to become dull, not lively, with the continuation of the lack of light; this drawback is found particularly with those varieties with pink or purple variegation. During the summer months the cordilinee can be placed outside, in a bright place, but sheltered from direct sunlight.
From March to October, water the cordilineae regularly, leaving the soil to dry between one watering and another; during the cold months water only sporadically, taking care to vaporize the foliage with demineralized water, every 6-10 days, to increase the environmental humidity. During the vegetative period, provide fertilizer for green plants, every 20-35 days.
Grow the cordilinee in a good rich and well-drained soil; a suitable substrate can be prepared using balanced soil mixed with little river sand and a few perlite or lapillus. Generally they do not develop a conspicuous root system, and are repotted every 3-4 years.
The basal suckers are detached in the months of March or April and are packed in 10 cm containers. They are cultivated in a protected environment, taking care that the temperature is around 10 ° C, and after a year they are repotted and placed in the open air.
As cuttings you can use the stems of old plants cut into portions of about 8 cm that are vertically put together in a compound of peat and sand in equal parts. When the tips of the shoots begin to appear, the cuttings are potted in containers of about 8 cm.
The multiplication can also be done by sowing in April in containers with a compost for sowing. When the seedlings are large enough, they are repotted in containers of about 6 cm.
Cordilinea - Cordyline australis: Parasites and Diseases
They can suffer from accesses of watering, or lack of drainage, developing root rot; sometimes they are attacked by aphids or cochineal.