Mallee’s are generally under utilised in cultivation. They are a significant group of horticultural plants that are particularly ornamental and extremely tough in hot & dry environments, but their lack of use is probably from a lack of information. The word mallee is primarily a term used to describe a group of Eucalyptus species with a particular growth form and habit.

HISTORY OF THE TERM "MALLEE"

The word “Mallee” is derived from the aboriginals describing the species of Eucalyptus that dominated the scrubby dry areas in which they grew and provided them water from their roots. This allowed them to travel for short periods of time into these dry areas, especially during long hot summers and times of drought. Shallow trenches were dug to expose the long reaching roots and cut into short lengths to extract water. Examples of species used for water were:
Eucalyptus socialis, E. dumosa, E. behriana and E. leptophylla

The early European settlers adopted the term “Mallee” to describe the multi-stemmed species of Eucalyptus that dominated the scrubland throughout southern Australia. Mallee vegetation has only been of interest to conservationists in recent times due to the environmental issues of massive land clearing for cereal crop farming and the salinity problems that have since occurred.

GROWTH FORM AND HABIT

• Multiple stems at ground level arising from an underground lignotuber (commonly known as a “Mallee Root”)
• The stems are generally at an angle and are clearly visible forming a vase shape with an open umbrella type crown of foliage at the ends of the branchlets
• Usually less than 10 metres in height
• Wide spreading root systems used to find water, especially during the long hot summers and drought conditions
• Leaves are usually tough and leathery to minimise water loss and exposure
• New shoots will sprout from the lignotuber if branches are broken or burnt, producing “Whip Stick”new growth
  

Sometimes confusion can arise as to whether a species falls into the mallee category, for example

• A Eucalyptus tree may develop multiple stem regrowth after damage or fire from the lignotuber or epicormic buds beneath the bark
• A species that normally grows as a mallee habit may occasionally develop a single stem, especially in cultivation
• A species that normally has a single trunk may develop multiple stems as a reaction to extreme environmental conditions, e.g. strong coastal winds

NATURAL HABITAT

Mallee’s generally grow in communities dominating the landscape with a uniform height. Often these communities appear to be the one species, however at close inspection they are can be a mix of several species. The soils are usually sandy, nutrient deficient & alkaline. The maximum height of a species may vary from location to location due to changes in soil type, e.g. nutrient depleted pale sands usually produce shorter communities than those on red-brown loam. They have the ability to survive extremely harsh environments, especially drought, and are long lived due to their ability to regenerate new grow quickly from their lignotuber after fire or damage.

DISTRIBUTATION

In general, the term describing the “Mallee Region” is where Mallee’s dominate the landscape and the climatic conditions are generally hot, dry summers and wet winters, with an annual mean rainfall from 200 to 600mm. These areas are:

• Generally the southern fringe of Australia, south of latitude 32 °

• Inland areas of Western Victoria and south-western New South Wales

• Inland and coastal areas of southern South Australia

However the majority of species are from inland and coastal areas of southern Western Australia, which include the most ornamental.

Natural stands of dry mallee scrub vegetation in the “Mallee” region of north-western Victoria can still be seen in various national parks and reserves such as Wyperfeld, Pink Lakes, Hattah Lakes, Big Desert and Sunset Desert. These include:

Eucalyptus oleosa – Oil Mallee
Eucalyptus socialis – Red Mallee, Grey Mallee
Eucalyptus gracilis – White Mallee, Yorrell
Eucalyptus calycogona – Square-fruited Mallee
Eucalyptus foecunda – Narrow-leaved Red Mallee
Eucalyptus dumosa – Dumosa Mallee
Eucalyptus incrassata – Yellow Mallee
Eucalyptus behriana – Bull Mallee

MALLET AND MARLOCK HABIT

These two groups of Eucalyptus species are very similar in appearance and size and are often grouped with Mallee’s. The main difference being that they do not have a lignotuber and only naturally occur in Western Australia.

Mallet’s have a short single trunk with multiple steeply angled branches, e.g Eucalyptus diptera – Two-winged Giblet.

Marlock’s are singled stemmed with multiple branches close to ground level and dense foliage giving it a shrub like appearance, e.g. Eucalyptus platypus

HORTICULTERAL NOTES

Mallee’s, Mallet’s and Marlock’s are extremely useful and multi-purpose plants with the following attributes:

• Small size and attractive habit is good for home gardens, commercial and public areas and street planting
• Respond extremely well and thrive in cultivation where size and shape are improved
• Many can be trained as a single trunk if this is desirable
• Provide light shade which will allow understorey plants to grow
• Heat and drought tolerant, in fact often thrive in such conditions
• Long lived due to the ability to regenerate quickly after fire or damage
• In general they do not like waterlogged soils, however the Western Australian species are generally not as fussy as other Western Australian natives such as Grevillea or Banksia species which can be difficult to grow with out perfect drainage
• Many species have extremely ornamental buds, flowers, fruit, foliage and bark
• Often the smaller Mallee’s have the largest buds, flowers and fruits which make attractive feature plants e.g. Eucalyptus rhodantha
• Many are suitable for fresh and dried flower arrangements
• Encourages native birds and other wildlife into the garden
• Excellent as hedges and wind breaks
• Shelter for live stock
• Used in re-vegetation of land especially in areas affected by salinity
• Many will tolerate coastal areas with some protection
  
  
  

CULTIVATION

Most Mallee, Mallet and Marlock species prefer a Mediterranean type climate, meaning hot dry summers and cold wet winters or semi-arid climates which are hotter and drier again. However there are some species from humid climates, e.g. Eucalyptus curtisii which naturally occurs in Queensland.

Other points to consider for successful cultivation:

• Most species prefer well drained soils, however some species can grow in waterlogged soils e.g. Eucalyptus kitsoniana
• Most species will cope with frost however it always helps to protect plants while young
• Water in new plants and continue to give a good drink once a week for the first summer then once a fortnight the second summer or until established.
• Fertilise as you would for most native plants however they generally do not required it unless the plant looks like it is lacking