Tropical plants are very popular among householders, not only for decorative effects but also for commercial uses. The prominence of the horticultural industry in Australia is due to the production of many tropical plants, some of which are readily propagated, whereas others require special attention if they are to be successfully raised from seed or tissue culture.
This article briefly outlines some of the more common tropical plants that are often found growing under glass in conservatories and on window ledges at home. These plants will grow well throughout most parts of Australia, provided they have adequate light and moisture during the warm summer months and a good temperature range with protection against the direct sun during winter. Where such conditions do not exist in the home or glasshouse, they can be readily supplied by artificial light and heating.
In many respects, the growing of tropical plants is no different from growing other types of plants in a garden, with one important exception – their cultural requirements are much stricter in some respects. Basic knowledge of their cultural needs is necessary if satisfactory results are to be achieved. These may best be summarised as follows:
- Propagation for commercial purposes usually involves rooting cuttings taken during winter when atmospheric humidity is lower than at any other time of the year. Cuttings prepared for rooting should have a growth point and a reasonable length of the stem, which contains young leaves on the lower portion so that transpiration is maintained at a reasonable level during the rooting process. A shallow tray containing a well-drained medium is required for cuttings.
- Growing on the young plants requires the use of an open, friable mixture rather than a closed one that contains plenty of humus but is too heavy to allow good aeration around the roots. This will be discussed in more detail later on.
- The most difficult of all cultural requirements are keeping sufficient humidity with ample light until new leaves are formed with no exposed midribs – this applies particularly to seedlings and smaller plants that require misting or spraying at regular intervals during hot weather or strong sunshine. Misting becomes less important as the foliage increases in size, provided there is sufficient light intensity to prevent the burning of the leaves.
When you first walk into an exotic plant shop, the plants are usually arranged in pots. When you choose a plant to buy or have one chosen for you by someone who works there, it will have its roots wrapped up in something wet. This is because it is likely that if left unwrapped, the roots might dry out before you could get them home. Most of us put our newly purchased plants straight into larger pots at home and then find that they do not need watering again for about two weeks. At this point, we often forget to keep checking how much water they need and be shocked when they become pot-bound.
The easiest way to solve this problem is to use special pots designed for tropical plants called hydro-pots. These pots have a growing medium in them, which consists of small pieces of bark and peat moss. When placed in water, the bark and moss absorb this water until they expand to about eight times their original volume. As a result, when your plant is potted up in these containers, it will only need watering every two weeks or so. In addition, because all the roots are surrounded by a wet medium, there is no chance for the roots to dry out at all.