SCIENTIFIC NAME: Carya illinoinensis
FAMILY: Juglandaceae

The graceful, stately, pecan tree is a big asset for a garden. It is not suited to all suburban blocks because it grows up to 10, sometimes 15 metres high. However, where you can fit in one or two trees, you will be rewarded with a lifetime of nuts.

Pecans can easily live to be 100 years old and some trees in the Mississippi delta are known to be 1000 years old. They are well-suited to many areas of Western Australia because they enjoy long, hot summers that are, in fact, necessary to mature and fill out the fruits.

The natural growing region for pecans in WA extends from north of Carnarvon, north of Wiluna through to an area east of Esperance and includes most of the South-West, barring the wetter portions close to the south coast.

The pecan nut has a wide range of uses in the kitchen. It can be added to sandwiches and salads and baked in sweet breads. Of course there is the famous and delicious pecan pie.

The nuts are harvested in autumn and are somewhat oval in shape with pointed ends. Some varieties drop their nuts when they are mature and others need to be knocked down with long poles. Once the nuts have been harvested, it is advisable to crack the outer shell and remove the nut meat. This can then be frozen in sealed plastic bags for up to 12 months.

These tall, stately trees can bear their first crops four to seven years after planting. This is for grafted trees; seedlings may take many more years. The trees have what is called a low-to-medium chilling requirement - they do need some cold winter weather to set the wood and let flowers form in the spring.

The climate of the suitable growing area in WA satisfies this amount of winter cold. Because of the large size of the trees, it is not advisable to plant them within five metres of buildings or sewerage lines. Pecans can tolerate infertile sandy soils, however, best results are achieved when it is planted in deep, fertile loams.

The flowers are in drooping catkins and are not showy. The tree is pollinated by wind. While pecans have male and female flowers on the same tree, in most cases there is not sufficient crossover to achieve good pollination. It is therefore recommended that two trees of different pollinating varieties are planted together. There are a couple of varieties, however, that are self-fertile, sufficient to give a home gardener a good crop from one tree.

Pecans are deciduous trees and can be most majestic when fully mature. They give a lovely deep shade, and because of their bushy nature, can be used as a large screening tree. They look tremendous when planted along the line of a driveway.

The temperature of your house can be dropped by four to five degrees in summer with a pecan planted on the north side of the home, where it can shade those exposed walls. Irrigation and fertilisers help pecans to grow. Their natural habitat is rich alluvial river flats, often with their roots tapping into fresh water.

A mature pecan tree needs to be producing new growth to a length of 20 cm to 40 cm each year to be growing well. Anything short of 20 cm of new growth means that it needs additional fertiliser. Zinc is one of the critical minor trace elements required to grow pecans successfully. This can be applied either as a foliar spray of zinc sulphate or a side dressing of superphosphate with copper and zinc added.

Pruning is needed only in the early stages to shape the tree and is not required annually. Early training should aim to encourage the natural pyramid-shaped growth pattern, to develop wide crotch angles for the branches and to remove any criss-cross growth in the centre of the tree.

Transporting a fruiting tree from its natural habitat, in this case from North America to a completely foreign environment, often eliminates many of the natural pests and diseases. This is the case with the pecan, which is relatively free of problems in Australia.

There are a wide range of varieties available. Some of the recommended ones for this area are Chickasaw, Shoshoni, Cherokee (this is a very early-bearing precocious tree) and Western Schley. Western Schley is a late-season variety, but is the best one for single plantings for the home gardener, as it is reliably self-fertile.

Pecans are a long-term investment for the gardener. It may well be that your children and grandchildren will reap the greatest rewards from planting.

Neville Passmore
Quandong magazine of the
WA Nut And Tree Crop Association Inc. November, 1987

DATE: September 1988

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