Sep 052013
 


As summer approaches our taste buds tingle in anticipation of luscious mangoes and other tropical delights. What better than to grow your own? Don’t be put off by the fact that you live in Melbourne, it is possible to grow a range of tropical and subtropical fruit varieties down here. The key to success with tropical and subtropical fruit is finding or creating the right spot or microclimate in your garden that will provide a warm, frost-free environment for optimal growth, flowering and fruiting, as well as providing a well-drained but moist soil. There is nothing quite like the taste and smell of ripening tropical fruit in summer, why not give it a try?

Winter temperatures will determine if tropical and subtropical plants will survive, while summer temperatures and the number of growing days will determine growth and fruiting success. Most subtropical plants will survive temperatures as low as -1 degrees Celsius while tropical plants prefer the lowest temperature to remain between 4 and 10 degrees Celsius.

What is a microclimate?

A microclimate is the climate of a small or restricted area, in contrast with the climate of the surrounding area. The climate of a particular area is affected by many factors such as topography, soils and vegetation. Aspect (the orientation in relation to the sun) is also important to consider when planting crops.

There are many ways to create a warm microclimate on a suburban scale in your backyard. The air temperature can be increased by the use of thermal mass to absorb and store heat. A simple example of this is the warmth a north or east facing brick wall will absorb and then slowly radiate into the surrounding area. Citrus trees often do well when planted near a brick wall for this reason and, similarly, an avocado or custard apple will benefit. Paving, rock terraces or even gravel can have a warming effect on the air temperature in your garden.

It is important to prevent wind from removing the air once you have warmed it. Using dense plantings, fences and walls to block, or slow wind will ensure that the air temperature remains warmer for longer. Strategically planted deciduous trees have the advantage of allowing winter sun to penetrate into the area to warm the soil, while still reducing the impact of the wind.

Swimming pools, water tanks (as thermal mass) and ponds can also assist with the creation of a frost-free microclimate. Water will absorb heat and cool off slowly and also impact on the surrounding temperature through evaporation, increased humidity, and reflected light. Even a small pond can have a warming effect on the temperature of an area.

Of course an easy way to create a microclimate is by having a green house or similarly protective structure that can house tropical plants, protecting them from cold weather.

We do try and keep all of the following varieties in stock, but seasonal availability means that some of these may not be available all year round.

Subtropical plants

Avocado (Persea americana)

Avocadoes do extremely well in Melbourne and are tolerant of the cold although not of frost when young. To ensure fruit production you should always purchase a named cultivar from a nursery, rather than growing from a seed. Fruit will be produced in 3 or 4 years from a grafted plant. They prefer a free-draining soil, as they are inclined to root-rot, so ensure that your soil does not become waterlogged. Avocadoes should be planted in a sheltered and frost-free position with some protection from the hot afternoon sun. Mulch well to protect the shallow roots and feed with well-rotted poultry manure. Melbourne varieties include Fuerte, Wurtz and Reed. For more detailed information, see our Avocado Factsheet.


Babaco (Carica pentagona)

The babaco is related to the pawpaw and is great option for cooler climate paw paw lovers. It produces abundant sweet, juicy fruit along the trunk of a self-fertile small tree that reaches about 2.5m. It needs a frost-free position with some protection from hot afternoon sun and plenty of mulch to keep the shallow roots cool. Harvest fruit during summer and autumn. Babaco trees may lose their leaves in winter. For more detailed information, see our Babaco Factsheet


Cherimoya / Cold Climate Custard Apple (Annona cherimola)

An elegant semi-deciduous tree that is useful as a shade provider. The flesh can be eaten fresh or made into sorbet and smoothies, although the seeds are said to be toxic, so remove those first. The cherimoya requires a free draining soil with consistent moisture and good wind protection. The tree can be pruned to establish a strong framework when first planted and requires feeding with compost and mulch to provide nutrients. Hand-pollination is recommended in order to ensure a sufficient crop.


Curry Leaf (Murraya koenigii)

The curry leaf tree is an attractive, weeping tree that will reach about 2m in Melbourne. It requires a sunny, protected, frost-free position and, although evergreen, may lose leaves over winter in colder areas. It requires protection from frost and a free-draining but moist soil. The leaves are used in curries and other dishes, either dried or fresh.


White Sapote (Casimiroa edulis)

The white sapote has similar growth requirements to a lemon, so if your lemon is thriving you could try growing a sapote. This partially self-pollinating tree produces a round, green fruit, similar in size to an orange, with pale custardy flesh. Some require cross-pollination. It requires a warm sheltered position with good drainage. Feed with plenty of organic matter and fertilise with manures or blood and bone. Ensure that it does not dry out over summer but do not allow it to become waterlogged. The tree is quite vigorous and can produce long shoots, resulting in tall leggy growth. With diligent pruning of the shoots the tree can be kept as short as 2-3m. Harvest fruit from March to May.


Tropical Plants

Acerola Cherry (Malpighia glabra)

The Acerola or Barbados cherry is a self-pollinating shrub or small tree that will reach between 2 -5 m in height. It is grown for the bright red cherry-sized fruit in summer. They are similar in taste and use to a crab apple, although sweetness varies. It prefers a well composted and mulched fertile and rich soil, but will not tolerate water logging or frost. Fruit bruise easily. Grow in full sun. High in vitamin C.


Bananas (Musa spp.)

Bananas in Melbourne will take longer to fruit, (up to two years), than when grown in the tropics. A well drained soil is necessary, as the plant can rot at the base, but it needs to be rich in organic matter, so add plenty of well-rotted compost and mulch well. The roots are mat-forming so prepare the soil in a wide rather than deep fashion. It prefers a frost-free, north-facing position with little or no wind. The types of bananas available for growing will be either a Cavendish or Lady Finger variety. The bananas growing in this pic are in the front yard of Annie’s house in Brunswick, just in case any of you were doubting us!


Coffee (Coffea arabica)

The coffee plant is a small tree to about 2.5m. It will grow well in a sheltered, warm sunny position but really does best in temperatures above 5 degrees Celsius and will only fruit in a greenhouse. The coffee plant will not tolerate wind or waterlogging so requires a rich, fertile and free-draining soil. It has glossy, dark green leaves and is useful as an indoor foliage plant in cooler climates. Berries are harvested during winter when they are bright red, so the tree requires adequate food and moisture during spring and summer. Mulch well and use compost and well rotted manure. Generally the berries contain two coffee beans.


Dragonfruit or Pitaya (Hylocerus undatus)

A highly ornamental fruit with brilliant pink skin and flesh dotted with tiny black seeds. The fruit is borne on an epiphytic cactus and it has a crunchy sweet texture. The cactus has aerial roots and will adhere to a trellis or wall, reaching about 3m in optimal conditions. Grow the dragon fruit in a sunny, frost-free position with a moist free-draining soil. It will grow well in a pot if an adequate climbing support is provided. It fruits during summer and autumn. If cropping is poor try hand-pollinating the flowers and feeding with a seaweed fertiliser.


Mango (Mangifera indica)

A large and dense shade tree in tropical climates, the mango needs a bit of loving in Melbourne. Once it is established it will tolerate light frost (-1 degree Celsius) but until then it needs protection during the colder months. Provide a slightly sandy, free-draining soil and fertilise with blood and bone until it starts to bear fruit, in about 4 to 10 years. They may be pruned to establish a strong framework when first planted. Grafted mango varieties Nam Doc Mai, Kensington Pride and R2E2 are some of the varieties suitable for Melbourne. For more detailed information, see our Mango Factsheet.

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