There are three major environmental considerations to be made when selecting trees: climate, soil and available space. Many trees are intolerant of wind or suffer through excess or insufficient moisture at various times. For instance, in the Tully region, rain frequently washes pollen off mango flowers, resulting in unsatisfactory fruit setting. The type of soil and drainage, although important for some of the more demanding trees, can, with modern methods and some effort, be improved to suit all but the most demanding species. Space is a real limitation. A huge tree in a small yard is rarely advisable; several smaller trees will add variety and interest.

When buying trees one should consider the appearance of the seller's premises and his knowledge. Trees flourishing under 80% shade cloth will probably not thrive as easily in a yard as those which come from 50% shade. Potted avocados should not be kept on soil since the dreaded soil fungus, Phytophthora cinnamomi, may invade the pot. Citrus trees are government controlled and only certified budwood and seeds are used by a few highly sophisticated nurseries in Queensland.

Visual inspection of a tree prior to purchase is most important. A tree should be vigorous. Plants with new growth are likely to be in good health (other than dormant periods). Check the trunk: it should have an appropriate thickness and no scars, with the graft well healed or painted with grafting wax. The foliage should be true to type and of good colour. Yellowish new growths indicate iron or manganese deficiency.

Buyers frequently worry that plants might be root-bound. Certainly the container should be of an appropriate size. It is interesting to observe that different type pots result in different types of root formation. Tins with holes in the bottom induce roots to circle in that bottom crease. Plastic pots are much better in appearance and rigidity. The drainage holes in the bottom corner interrupt the root circling to some extent. However, the 'el cheapo' plastic bag stirs roots up most effectively and is best in regard to root formation of potted trees.

The choice between a grafted specimen or a seedling is usually simple. Almost always the grafted fruit will be of a superior quality. Grafted trees tend to be smaller, more bushy and frequently fruit several years before a seedling would. However, a seedling is more robust and sometimes no superior grafted varieties are available. Finally, many superior cultivars are derived from chance seedlings, so, if you are ambitious, plant many seedlings!....

The price of the tree can be of interest. Compare not only the price but also the tree you are getting for it. Remember, John Ruskin said: "It is unwise to pay too much, it is worse to pay too little."

Harry Wilcheski, RFC Townsville
(Précis by Jim Darley)

DATE: August 1981

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