Houseplant: Tillandsia

These veritable ‘gems’ of the plant realm could be the subject of a whole book or website, and not an uninteresting one at that. Nor is it surprising that there are already numerous tillandsia clubs throughout the world, for the requirements and bizarre appearance of many species must captivate every nature lover.

No other plants exhibit such great diversity within a single genus. Many tillandsias are ‘typical’ bromeliads in that their leaves form the characteristic funnel-shaped rosette to catch and hold rainwater. In others the thickened bases of the leaves form a kind of bulb serving to store water inside the tissues, covered with a thick skin. Tillandsia us-neoides, one of the best-known, looks like a lichen of the genus Usnea; it has no roots and the stems with narrow leaflets trail freely in space like tufts of grey hairs. The varied environment in which these plants grow was naturally responsible for these morphological adaptations. That is why it is also relatively easy to guess from its shape what the requirements of a given plant are. The broad, green leaves of Tillandsia imperialis arranged in the form of a regular funnel indicate that this plant comes from an environment with frequent rains and only brief periods of drought, and so it does — in its native land, Mexico, it grows at elevations of 1,700 m (5,650 ft) where the marked fluctuations between day-time and night-time temperatures assure an adequate daily supply of dew.

The leaves of T. dasylirifolia likewise form a funnel, but different from that of the preceding species. The leaves are stiff, or rather hard, and fairly narrow, widening only at the base, where the plant stores water. The leaves are also covered with absorbent scales that enable the plant to utilize even water from mist by absorbing it and passing it on to the inner leaf tissues which are protected by a rigid epidermis. The surface of the leaves is a striking colour — green coated by a blend of copper, red, violet and grey. Such colouring usually serves as protection against too much sun — and from this we can deduce the plant’s requirements: full sun, heat and drought. Often it grows on columnar cacti, to which it holds fast by means of several wiry roots that have long lost their original function. Water and food are obtained only through the leaves. Many tillandsias growing in localities subject to drought are spherical in shape (the smallest surface area and hence the smallest amount of evaporation), with leaves that are narrow to thread-like and thickly covered with absorbent scales. Examples of such tillandsias are T. tectorum (syn. T. argentea) and T. filifolia. Elsewhere we will find clumps of plants that collectively form a spherical shape; this habit is characteristic, for example, of T. ionantha (syn. T. erubescens) and T. recurvata; the latter is often found growing on telegraph wires.

T. imperialis

However, it is not only the shape and interesting adaptations that attract the interest of growers. Til-landsias also have lovely flowers, be it the large gentian-blue flowers of T. cyanea arranged in a flat spike or the simple dark blue flowers of T. brachy-caulos emerging from the centre of the rosette and forming a striking contrast with the brilliant red leaves of the rosette. This is not the only species whose leaves turn red during the flowering period; the same is true, for example, of the already men-tioned T. ionantha.

To be grown successfully, these magnificent bromeliads must be put in a warm spot in full sun, best of all in a southern or eastern window. They should be put on branches or on pieces of cork oak bark (the roots of grape vine are also excellent), to which they should be tied with a thin, coated wire or strip of nylon stocking; small species and seedlings may be attached to the bark with waterproof glue. Tillandsia cyanea, T. brachycaulos and large rosette-forming species may also be grown as potted plants in a light soil mixture, such as one of the soilless composts. Water and feed are best supplied by syringing the leaves, but it must be remembered that purely epiphytic forms tolerate only very low concentrations of fertilizer. Propagation is easy — by detaching young plantlets growing from the side or by means of seeds sown on the surface of the branch immediately after they have ripened, for they rapidly lose their powers of germination.

15. November 2011 by Dave Pinkney
Categories: Featured Articles | Comments Off on Houseplant: Tillandsia

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