There are Eucalypt varieties which will suit most temperate, sub-temperate or tropical climates, and some which will adapt to most soil conditions.
In California, Eucalypts have been growing so widely for so long that they are thought by some locals to be an American native. In Italy farmers use Eucalypts as windbreaks around their paddocks.
The English sometimes use attractive blue foliage Eucalypts as bedding plants among annual flowers and as indoor plants. Eucalypts have been used for land reclamation in desert areas and the Israelis have found certain varieties of River Red Gum to be an ideal plant to grow in salt contaminated soils.
There are 8 lessons in this course:
Review of the system of plant identification, general characteristics of the group, information contacts (ie: nurseries, seed, clubs etc.)
Planting, staking, mulching, watering, pest & disease, feeding, pruning, protection from wind, salt air, etc.
Methods of propagating this group of plants.
The most commonly grown varieties.
Other important groups.
Lesser grown varieties.
Making the best use of Eucalypts
Special Assignment. On one selected plant or group.
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.
Describe the classification of Eucalypts.
Discuss general cultural requirements for growing Eucalypts.
Differentiate between identifiable characteristics and cultural requirements in a number of commonly cultivated Eucalypts.
Discuss characteristics of a wider range of Eucalypt species.
Describe commercial uses for a range of different Eucalyptus species.
Plan the establishment of a collection of different cultivars of Eucalypts (eg. Gums, Mallees, Tall Trees, Short Trees, Dryland Species), suited to growing in a specified locality.
WHAT ARE EUCALYPTS?
Eucalyptus is one of many genera belonging to the Myrtaceae family.
Until relatively recently, all eucalypts were considered to be in the genus "Eucalyptus"; but botanists have divided the genus into two genera in more recent times (and some into three). Many people may still refer to them all as Eucalypts, but some will have adopted the change.
Other genera in this family include Callistemon, Melaleuca, Leptospermum, Bauera, Thryptomeme, Angophora, Tristaniopsis, Lophostemon, Feijoa and Myrtus. (Angophora was originally a Eucalypt too!)
The family includes both trees and shrubs and is characterised by the oil glands in the leaves, leaves which are usually opposite but sometimes alternate, their evergreen habit and leaves which are usually entire (ie. not divided). Flowers are normally in cymes. Calyx is 4 or 5 free or united sepals. Corolla is 4 or 5 free or united petals. Normally large numbers of stamens. Fruit is a berry, drupe, capsule or nut.
EUCALYPTUS AND ITS CLASSIFICATION
One form of classification divides the Eucalypts into 8 groups or sections as follows:
(Sections can be distinguished by structure of the anthers (ie. male parts of the flower which produce the pollen, you need a magnifying glass or microscope to distinguish apart).
A. SECTION MACRANTHERAE
Anthers are versatile, normally large.
Includes E.erythrocorys, E.tetraptera, E.calophylla, E.diversifolia, E.platypus.
B. SECTION RENANTHEROIDEAE
Anthers versatile, broad parallel, sublique cells, large gland at tip or sub tip.
C. SECTION RENANTHERAE
Includes E.radiata, E.marginata
D. SECTION PORANTEROIDEAE
Anthers adnate, globular, subcuenate to reniform
Anthers nearly all perfect.
Includes E.microcarpa, E.albens, E.bicolor.
E. SECTION TERMINALES
Many of the filaments without anthers, anthers adnate, erect or oblique on filament, cells normally
distinct opening in ovate slits or circular pores at the tip.
Includes E.sideroxylon, E.leucoxylon.
F. SECTION GRACILES
Outer filaments infertile and much longer than inner fertile filaments.
Includes E.fracilis, E.calcycogna.
G. SECTION MICRANTHERAE
Anthers open in front (not on top) in broad oval pores. Filaments normally fertile.
Includes E.micranthera, E.cneorifolia.
H. SECTION PLATYNANTHERAE
Anthers open in front or along sides with long slits or pores.
Includes E.gilli, E.macrocarpa, E.salmonophloia.
There are other variations on this classification as well.
Recent times have seen a large number of plant genera being renamed by botanists and herbariums. Eucalyptus genera have also been subjected to this renaming process. It is worth noting that many grower groups, professional bodies, clubs and societies, have either declined the name changes or have opted to take the standing of waiting for a longer period before adopting these changes.
Acceptance of the genus Corymbia has at best been questionable, and many people you encounter may very well still only use the name “Eucalyptus”.
Although most home gardeners and collectors are not concerned with name changes like this, it is worth noting that in the professional fields of botany and horticultural media the change has occurred. Whether or not these changes will be accepted globally may take years to settle the dispute.
ANOTHER WAY OF NAMING EUCALYPTS
The above subdivision of eucalyptus is scientific, and as such very precise.
Other methods (less precise) also exist for classifying Eucalypts into different groups.
Perhaps the most common one is the following:
- The Gums
- The Boxes
- Ironbarks etc.
This method is based on differences in the appearance of the bark or the trunk.
Eucalypts hybridize very easily. Many seedlings found growing both in home gardens and in the wild are very difficult to identify because they are in fact a cross seedling between two other varieties growing nearby. If you can identify the others in the vicinity, you may be able to take an educated guess at what the hybrid is.
WHO CAN BENEFIT FROM THIS COURSE?
- Anyone else who deals with plantin or managing trees
Some of our students take this course because they have a simple passion for eucalypts; but for most, they are enhancing their knowledge of eucalypts in order to help them in their business or career.
Eucalyptus is an important genera for plant nurserymen, landscapers and foresters the world over. It's commercial significance is so great that some academics devote a significant part of their career to research or cultivar breeding of eucalypts.
Different students will have different reasons for studying this course. All though, will complete the course with an expanded knowledge and awareness, as a step toward ever expanding expertise with the genus Eucalyptus.