Tropical Plants

Become an expert in the identification and culture of tropicals

• Grow tropicals as garden plants (if the climate fits), as greenhouse (stove) plants or as indoor plants.
• Professional Development - advance a horticultural career
• Work in or Start a nursery or plantscaping business
• 100 hour, self paced course -upgrade prior qualifications or combine with other modules for a certificate

You don’t necessarily have to live in a warm climate to have tropical plants; there are plenty of ways of adapting the environmental conditions to suit them.” - Tracey Morris Dip.Hort., Cert.Hort., Cert III Organic Farming, ACS Tutor.

Lesson Structure

There are 10 lessons in this course:

1. Introduction to Tropical Plants
   • Plant names/classification (scientific & common), climatic conditions, plants suited to the students locality.
2. Plant Cultural Practices
   • Understanding soils, naming a soil, propagation, watering, feeding, pruning etc.
3. Tropical Annuals, Perennials, Bulbous Plants, Bamboos & Lawns
4. Ornamental Gingers and Heliconias (and related plants including Alpinia, Hedychium, Zingiber, Musa & Costus
5. Cordylines, Palms & Cycads
6. Climbers, Shrubs and Trees
7. Orchids, Ferns, Aroids and Bromeliads
8. Tropical Herbs, Vegetables and Fruit Bearing Plants Including Bush tucker, Selected Vegetables, Tea & Coffee, Tropical Fruit trees
9. Growing Tropical Plants outside the Tropics
   • Growing tropicals indoors, in different climates and conditions.
10. Landscaping with Tropical Plants
    • Use of colour & texture, plant selection, planting a courtyard, preparing sketch plans.

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

Aims

• Explain the nature and scope of tropical plants
• Discuss cultural characteristics that are often peculiar to tropical plants
• Describe the taxonomy and culture of a range of soft wooded tropical plants including annuals, perennials and bulbs.
• Describe the taxonomy and culture of Heliconias and Gingers..
• Describe the taxonomy and culture of Palms and Palm like tropicals.
• Describe the taxonomy and culture of climber, tree and shrub tropical plants.
• Describe the taxonomy and culture of Orchids, Ferns and Bromeliads.
• Describe the taxonomy and culture of Herbs, Vegetables and Fruits in tropical conditions.

TROPICALS ARE NOT ALL THE SAME

GROWING IN HOT DRY AREAS

Water is the most important commodity in an area which is dry. Rain is infrequent, although it may be torrential when it does occur and will be responsible for flash flooding followed by great bursts of greenery and growth which soon wilts once the excess moisture has evaporated. The problem posed for the dry climate gardener is how to conserve this excess water and make the most efficient use of it until the next rains occur.

The watering requirements of your plants can be minimised in the following ways:

•  By choosing plant species and varieties that best suit the local climate.
•  By maintaining a well balanced fertile soil (appropriate to the plants selected).
•  By watering in the cool of the day.
•  By using micro‑irrigation systems e.g. trickle systems where possible.

These are much more efficient in their use of water.

•  By slow thorough watering. A thorough deep watering once or twice a week will be more effective than light waterings every day or two.
•  By avoiding spraying water on windy days.
•  By considering soil type when selecting a watering system.

Clay soils hold water well and will distribute it horizontally, so a drip system is suitable.

Water runs quickly through sandy soil and a micro spray, which distributes water over a broader area than a trickle system would be more suitable.

• By reducing excess evaporation. This can be achieved by covering bare soil.  Mulches, as well as reducing weed growth will reduce evaporation. Compact groundcovers will slow evaporation from the soil but they will use a lot of water themselves. Larger plants will shade the soil and limit evaporation but they can make getting water to the soil in the first place rather tricky.
• Rainwater tanks are useful methods of gaining extra water. The use of tanks in the city may require permission from your local government authority. Unfortunately some councils will not allow them at all, and some may require that they be of only a limited size and out of public sight. But if you can get one it can help save water rates as well as be a way of getting fresh rain water to drink. In some cities, however, it is not recommended to use rainwater for the household if there is any likelihood of pollutants being present in the rain water or collected off your roof as it passes across.
• By covering swimming pools and directing storm water into them (subject to the conditions set out in the point above). Have the pool surrounds sloping back a little towards the pool so that any splashed water will run back into it.

GROWING IN DRY SANDY SOILS

A useful hint for planting in dry sandy areas is to dig the hole two or three times larger than the pot size that you have to plant. It is best to dig out half of the soil onto one side of the hole and one half onto the other. This gives you two piles of the sand from the hole, to one pile add well rotted compost, peat moss, well rotted animal manure or some loam. Mix all these together, pop some down the hole to bring it to the correct level then place your plant into the hole and backfill with the remaining soil. Tamp down the area around the plant and water in. Any left over soil can be used to form a lip around the plant to create a small basin to retain water. The idea with this system is to give the plants a good growing environment but at the same time allow them to become accustomed to the soil in which they are expected to grow in.

Many gardeners now incorporate moisture holding additives into the garden to give their plants a fighting start. Some of these products hold water in crystal form so that it is still available to the plants, or increase the water holding ability of the soil by altering the surface tension of the soil particles. Most of these products only last from a few months to about one year. They are short term remedies only but do help to get the plants established.

GROWING IN THE HUMID TROPICS

When planning for the humid tropical gardens, issues such as water availability, while still important, are not as crucial as they might be for drier areas. Humid tropic species have similar water requirements to most other plant species. They, as do most species, require the most attention and watering when they are young and more susceptible to drying out due to their size. Once established however, they will survive quite happily on the natural rainfall that they receive. In fact rainforest plants are no more difficult to grow as a group than any other group of plants. While there are individual species that ARE difficult to propagate or grow, the same is true of the entire plant kingdom and rainforest species should not be shied away from because of this.

Timing and quantity of rainfall needs to be noted or recorded. It is important to know when heavy rain periods are due and the quantity expected to fall. Adequate drainage should be considered in wet seasons to remove excess rainfall to prevent damage to the site and gardens.

The dry season may demand supplementary irrigations for young plants or new gardens.

Humidity, combined with the temperature, tends to encourage fast healthy growth on most species from warm climates. It also tends to encourage various diseases. Plants from tropical climates tend to have a natural resistance to most fungal diseases. Plants from cool climates planted in tropical gardens will usually succumb to most diseases due to its unsuitability.

One of the biggest causes for plant death in the tropics is the result of gardeners attempting to grow unsuitable plants in the garden. Plants that have silvery, hairy foliage are usually poor plant selections for this climate zone. Plants with glossy waxy leaves are good selections. Just like all things in nature there are exceptions to the rules so it is wise to refer to books like this or seek advice from local professionals.

The location of the site on a hill can dramatically influence rainfall and temperature even if the hill is in the middle of a tropical district. Rain may tend to come from only one direction, consequently, the property may be on the "dry" side or "wet" side. Whether facing north or south will influence temperature on the site.

High altitude districts within tropical areas will have much cooler temperatures than those properties sited near the coastline.

Handy hints to assist tropical gardeners include:

•  keep fertiliser up to plants due to extended growing/flowering periods.
•  mulch the soil and encourage ground covers to prevent soil damage during the wet season and to conserve water in the dry season.
•  regular pruning/trimming may be required to keep plants under control and neat.
•  select plants that prefer the climate - disregard plants that do not cope well with humidity.

GROWING IN COASTAL AREAS

Coastal districts have their own share of gardening problems. The climate tends to be slightly warmer in winter and cooler in summer than areas a little inland due to shore breezes. Plants therefore placed in a protected site away from coastal winds tend to grow fast and healthy.

Plants exposed to coastal winds may be subjected to salt spray. This is regarded as the biggest problem for coastal gardeners. The selection of plants must therefore suit the general climate, tolerate coastal winds, withstand salt deposits on leaves and the ground, plus survive on usually sand, low fertility soils that do not hold a lot of moisture.

The range of suitable plants are generally those which come from similar environmental districts or those which exhibit:

•  hairy foliage
•  silver or grey foliage
•  compact habit
•  fine foliage

The further you go away from the sea shore, the less effect the salt-laden breezes have on plants. In one garden it is possible to have sensitive ferns on the protected side of the house, and have She oaks (Casuarina), Coastal Rosemary (Westringia) and New Zealand Christmas Bush (Metrosideros) on the other side exposed to the sea.

GROWING IN WINDY AREAS

Wind can cause severe damage to trees and shrubs. In storms falling plants can result in damage to buildings and other structures.

In warm climates strong winds come from storms; tropical climates are prone to cyclones and hurricanes close to the sea. Plants have however adapted to these climatic forces. Palms native to most islands do not fall over or get seriously damaged by strong winds or storms. Likewise many other plants are adapted to the climatic disturbances that occur naturally.

Brittle stemmed plants are prone to damage easily in even gentle winds. It is best to select trees and shrubs that exhibit flexible branches and limbs, strong roots, open canopy and vigorous growth.

Stalking may be needed on severely strong wind prone areas but should be kept to a minimum.

Windbreaks such as shade cloth, wind barriers, or similar can be used to reduce damage caused by winds. Planting a line of wind tolerant trees is one popular method used to reduce wind damage and intensity.

 
WHY DO PEOPLE STUDY TROPICAL PLANTS?

• A passion -collectors, breeders, enthusiasts come in all shapes and forms. Some work in horticulture, and for others it is a hobby, maybe even an obsession.
• To get a job -Knowing more about tropicals is a big bonus in all manner of horticultural jobs
• Professional Development -gardeners, horticulturists, nurserymen, landscapers, flower growers and others 
• Starting a business -a nursery, flower farm, plant hire business, landscape business

There are opportunities you might not have even considered!