Tillandsias

Brian Baldwin

In the crowded world of a tropical jungle, any plant which can survive in a location where no other plant grows has a great advantage. By surviving on an inhospitable site, a plant eliminates the problem of aggressive neighbours competing for water, light and nutrient. Of those plants which have founds a means of surviving where no other plants can, tillandsias are among the most advanced. In fact, tillandsias are often called "air plants" because of their ability to survive without soil, roots or water. They survive by clinging to rocks and trees, where they rely upon rain water and dust to supply all the moisture and nutrient that they will ever receive.

Botanists classify these remarkable survivors as epiphytic bromeliads. An epiphyte is any plant which does not live in soil, but survives by clinging to another plant. Epiphytes should not be confused with parasites however, because while a parasite obtains nutrient from its host, an epiphyte treats its host as nothing more than a platform to stand upon. It does not harm the host plant in any way. For the purpose of support, tillandsias produce a few wiry roots that are able to cling to almost any surface. While these roots are effective in supporting the plant, they do not play a role in obtaining moisture.

When botanists call these plants bromeliads, what they are simply saying is that these are members of the pineapple family. The family resemblance is actually quite obvious when you compare a tillandsia with the cluster of leaves seen on top a pineapple fruit. The pineapple-like leaf arrangement is a common feature to the whole family, and is actually quite a useful trait. By growing in this shape, the plant's body becomes something roughly comparable to a large funnel, which channels all rain falling within a relatively large area to the base of the plant. By doing this, members of this family which live in dry soils, or on the tops of trees are able to capture rain water, and direct it toward themselves before it has even hit the ground.

What makes tillandsias most unique, however, is their ability to survive without a functional root system. All moisture and nutrient required by the plant is absorbed directly through the leaves by means of the tiny silver scales which cover the plant. The thin walls of these scales permit water to enter the leaves, but prevent its escape. The silvery colour of the scales also helps the plant remain cool by reflecting a portion of the sunlight that reaches the plant. Because these scales are essential to the plant's survival, it is critical that they not be scuffed off. The scales are very delicate, so it is almost impossible to handle these plants without scuffing some of the scales off. For this reason, the plants should be handled as little as possible.

As you might expect, a plant that is able to cling to the top of a tree, and supply its needs from rain and dust is quite easy to take care of. If they are placed where they will receive bright filtered sunlight and normal room temperatures tillandsias demand very little else. Their need for water can be supplied by either frequent misting, or for those who cannot remember to mist a plant every few days, the entire plant can simply be immersed in room-temperature water for about half an hour every week to ten days. This will permit the plant to absorb all the moisture it will require for the next week or so. Where plants are misted, it is important to supply enough water to satisfy the plant's need before the thin film of moisture has evaporated. Another idea to help minimize the need for supplemental water is to grow your tillandsia plants in a kitchen or bathroom window, where the incidental humidity of washing dishes or having showers will supply them with water. In a well-used bathroom, these plants may need almost no care at all.

Since tillandsias in nature derive their mineral nutrients from dust dissolved in the rainwater that reaches them, their need for mineral nutrients is minimal. To supply the mineral nutrients required by the plants, a very small among to household fertilizer (20-20-20) can be added to the water the plants are soaked in every couple of months. The concentration of fertilizer should be about one tenth the recommended dose to prevent burning the plants.

When a mature tillandsia is well looked after, it is also not uncommon for these remarkable little plants to reward you by blooming. Flowers are produced in showy little blue, purple, red, orange or white spikes which arise from the centre of the rosette of leaves. Unfortunately, while flowering is a sign of good health and maturity, it also indicates that the plant is preparing to divert its energy into the production of several offsets, and to die. Following flowering, several offsets will usually be produce at the base of the parent plant, and the parent begins to decline. When the parent plant has faded completely, these babies can be detached and placed where they will survive on their own. If given good care, the plant should continue to grow and develop for several years before flowering and producing new offsets of its own.

Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.